~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
MOTOROLA MICROPROCESSOR & MEMORY TECHNOLOGY GROUP
M68000 Hi-Performance Microprocessor Division
M68060 Software Package
Production Release P1.00 -- October 10, 1994
M68060 Software Package Copyright © 1993, 1994 Motorola Inc. All rights reserved.
THE SOFTWARE is provided on an "AS IS" basis and without warranty.
To the maximum extent permitted by applicable law,
MOTOROLA DISCLAIMS ALL WARRANTIES WHETHER EXPRESS OR IMPLIED,
INCLUDING IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
and any warranty against infringement with regard to the SOFTWARE
(INCLUDING ANY MODIFIED VERSIONS THEREOF) and any accompanying written materials.
To the maximum extent permitted by applicable law,
IN NO EVENT SHALL MOTOROLA BE LIABLE FOR ANY DAMAGES WHATSOEVER
(INCLUDING WITHOUT LIMITATION, DAMAGES FOR LOSS OF BUSINESS PROFITS,
BUSINESS INTERRUPTION, LOSS OF BUSINESS INFORMATION, OR OTHER PECUNIARY LOSS)
ARISING OF THE USE OR INABILITY TO USE THE SOFTWARE.
Motorola assumes no responsibility for the maintenance and support of the SOFTWARE.
You are hereby granted a copyright license to use, modify, and distribute the SOFTWARE
so long as this entire notice is retained without alteration in any modified and/or
redistributed versions, and that such modified versions are clearly identified as such.
No licenses are granted by implication, estoppel or otherwise under any patents
or trademarks of Motorola, Inc.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# ireal.s:
# This file is appended to the top of the 060ISP package
# and contains the entry points into the package. The user, in
# effect, branches to one of the branch table entries located
# after _060ISP_TABLE.
# Also, subroutine stubs exist in this file (_isp_done for
# example) that are referenced by the ISP package itself in order
# to call a given routine. The stub routine actually performs the
# callout. The ISP code does a "bsr" to the stub routine. This
# extra layer of hierarchy adds a slight performance penalty but
# it makes the ISP code easier to read and more mainatinable.
#
set _off_chk, 0x00
set _off_divbyzero, 0x04
set _off_trace, 0x08
set _off_access, 0x0c
set _off_done, 0x10
set _off_cas, 0x14
set _off_cas2, 0x18
set _off_lock, 0x1c
set _off_unlock, 0x20
set _off_imr, 0x40
set _off_dmr, 0x44
set _off_dmw, 0x48
set _off_irw, 0x4c
set _off_irl, 0x50
set _off_drb, 0x54
set _off_drw, 0x58
set _off_drl, 0x5c
set _off_dwb, 0x60
set _off_dww, 0x64
set _off_dwl, 0x68
_060ISP_TABLE:
# Here's the table of ENTRY POINTS for those linking the package.
bra.l _isp_unimp
short 0x0000
bra.l _isp_cas
short 0x0000
bra.l _isp_cas2
short 0x0000
bra.l _isp_cas_finish
short 0x0000
bra.l _isp_cas2_finish
short 0x0000
bra.l _isp_cas_inrange
short 0x0000
bra.l _isp_cas_terminate
short 0x0000
bra.l _isp_cas_restart
short 0x0000
space 64
#############################################################
global _real_chk
_real_chk:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_chk,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
global _real_divbyzero
_real_divbyzero:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_divbyzero,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
global _real_trace
_real_trace:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_trace,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
global _real_access
_real_access:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_access,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
global _isp_done
_isp_done:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_done,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
#######################################
global _real_cas
_real_cas:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_cas,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
global _real_cas2
_real_cas2:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_cas2,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
global _real_lock_page
_real_lock_page:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_lock,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
global _real_unlock_page
_real_unlock_page:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_unlock,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
#######################################
global _imem_read
_imem_read:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_imr,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
global _dmem_read
_dmem_read:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_dmr,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
global _dmem_write
_dmem_write:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_dmw,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
global _imem_read_word
_imem_read_word:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_irw,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
global _imem_read_long
_imem_read_long:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_irl,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
global _dmem_read_byte
_dmem_read_byte:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_drb,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
global _dmem_read_word
_dmem_read_word:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_drw,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
global _dmem_read_long
_dmem_read_long:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_drl,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
global _dmem_write_byte
_dmem_write_byte:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_dwb,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
global _dmem_write_word
_dmem_write_word:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_dww,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
global _dmem_write_long
_dmem_write_long:
mov.l %d0,-(%sp)
mov.l (_060ISP_TABLE-0x80+_off_dwl,%pc),%d0
pea.l (_060ISP_TABLE-0x80,%pc,%d0)
mov.l 0x4(%sp),%d0
rtd &0x4
#
# This file contains a set of define statements for constants
# in oreder to promote readability within the core code itself.
#
set LOCAL_SIZE, 96 # stack frame size(bytes)
set LV, -LOCAL_SIZE # stack offset
set EXC_ISR, 0x4 # stack status register
set EXC_IPC, 0x6 # stack pc
set EXC_IVOFF, 0xa # stacked vector offset
set EXC_AREGS, LV+64 # offset of all address regs
set EXC_DREGS, LV+32 # offset of all data regs
set EXC_A7, EXC_AREGS+(7*4) # offset of a7
set EXC_A6, EXC_AREGS+(6*4) # offset of a6
set EXC_A5, EXC_AREGS+(5*4) # offset of a5
set EXC_A4, EXC_AREGS+(4*4) # offset of a4
set EXC_A3, EXC_AREGS+(3*4) # offset of a3
set EXC_A2, EXC_AREGS+(2*4) # offset of a2
set EXC_A1, EXC_AREGS+(1*4) # offset of a1
set EXC_A0, EXC_AREGS+(0*4) # offset of a0
set EXC_D7, EXC_DREGS+(7*4) # offset of d7
set EXC_D6, EXC_DREGS+(6*4) # offset of d6
set EXC_D5, EXC_DREGS+(5*4) # offset of d5
set EXC_D4, EXC_DREGS+(4*4) # offset of d4
set EXC_D3, EXC_DREGS+(3*4) # offset of d3
set EXC_D2, EXC_DREGS+(2*4) # offset of d2
set EXC_D1, EXC_DREGS+(1*4) # offset of d1
set EXC_D0, EXC_DREGS+(0*4) # offset of d0
set EXC_TEMP, LV+16 # offset of temp stack space
set EXC_SAVVAL, LV+12 # offset of old areg value
set EXC_SAVREG, LV+11 # offset of old areg index
set SPCOND_FLG, LV+10 # offset of spc condition flg
set EXC_CC, LV+8 # offset of cc register
set EXC_EXTWPTR, LV+4 # offset of current PC
set EXC_EXTWORD, LV+2 # offset of current ext opword
set EXC_OPWORD, LV+0 # offset of current opword
###########################
# SPecial CONDition FLaGs #
###########################
set mia7_flg, 0x04 # (a7)+ flag
set mda7_flg, 0x08 # -(a7) flag
set ichk_flg, 0x10 # chk exception flag
set idbyz_flg, 0x20 # divbyzero flag
set restore_flg, 0x40 # restore -(an)+ flag
set immed_flg, 0x80 # immediate data flag
set mia7_bit, 0x2 # (a7)+ bit
set mda7_bit, 0x3 # -(a7) bit
set ichk_bit, 0x4 # chk exception bit
set idbyz_bit, 0x5 # divbyzero bit
set restore_bit, 0x6 # restore -(a7)+ bit
set immed_bit, 0x7 # immediate data bit
#########
# Misc. #
#########
set BYTE, 1 # len(byte) == 1 byte
set WORD, 2 # len(word) == 2 bytes
set LONG, 4 # len(longword) == 4 bytes
#########################################################################
# XDEF **************************************************************** #
# _isp_unimp(): 060ISP entry point for Unimplemented Instruction #
# #
# This handler should be the first code executed upon taking the #
# "Unimplemented Integer Instruction" exception in an operating #
# system. #
# #
# XREF **************************************************************** #
# _imem_read_{word,long}() - read instruction word/longword #
# _mul64() - emulate 64-bit multiply #
# _div64() - emulate 64-bit divide #
# _moveperipheral() - emulate "movep" #
# _compandset() - emulate misaligned "cas" #
# _compandset2() - emulate "cas2" #
# _chk2_cmp2() - emulate "cmp2" and "chk2" #
# _isp_done() - "callout" for normal final exit #
# _real_trace() - "callout" for Trace exception #
# _real_chk() - "callout" for Chk exception #
# _real_divbyzero() - "callout" for DZ exception #
# _real_access() - "callout" for access error exception #
# #
# INPUT *************************************************************** #
# - The system stack contains the Unimp Int Instr stack frame #
# #
# OUTPUT ************************************************************** #
# If Trace exception: #
# - The system stack changed to contain Trace exc stack frame #
# If Chk exception: #
# - The system stack changed to contain Chk exc stack frame #
# If DZ exception: #
# - The system stack changed to contain DZ exc stack frame #
# If access error exception: #
# - The system stack changed to contain access err exc stk frame #
# Else: #
# - Results saved as appropriate #
# #
# ALGORITHM *********************************************************** #
# This handler fetches the first instruction longword from #
# memory and decodes it to determine which of the unimplemented #
# integer instructions caused this exception. This handler then calls #
# one of _mul64(), _div64(), _moveperipheral(), _compandset(), #
# _compandset2(), or _chk2_cmp2() as appropriate. #
# Some of these instructions, by their nature, may produce other #
# types of exceptions. "div" can produce a divide-by-zero exception, #
# and "chk2" can cause a "Chk" exception. In both cases, the current #
# exception stack frame must be converted to an exception stack frame #
# of the correct exception type and an exit must be made through #
# _real_divbyzero() or _real_chk() as appropriate. In addition, all #
# instructions may be executing while Trace is enabled. If so, then #
# a Trace exception stack frame must be created and an exit made #
# through _real_trace(). #
# Meanwhile, if any read or write to memory using the #
# _mem_{read,write}() "callout"s returns a failing value, then an #
# access error frame must be created and an exit made through #
# _real_access(). #
# If none of these occur, then a normal exit is made through #
# _isp_done(). #
# #
# This handler, upon entry, saves almost all user-visible #
# address and data registers to the stack. Although this may seem to #
# cause excess memory traffic, it was found that due to having to #
# access these register files for things like data retrieval and <ea> #
# calculations, it was more efficient to have them on the stack where #
# they could be accessed by indexing rather than to make subroutine #
# calls to retrieve a register of a particular index. #
# #
#########################################################################
global _isp_unimp
_isp_unimp:
link.w %a6,&-LOCAL_SIZE # create room for stack frame
movm.l &0x3fff,EXC_DREGS(%a6) # store d0-d7/a0-a5
mov.l (%a6),EXC_A6(%a6) # store a6
btst &0x5,EXC_ISR(%a6) # from s or u mode?
bne.b uieh_s # supervisor mode
uieh_u:
mov.l %usp,%a0 # fetch user stack pointer
mov.l %a0,EXC_A7(%a6) # store a7
bra.b uieh_cont
uieh_s:
lea 0xc(%a6),%a0
mov.l %a0,EXC_A7(%a6) # store corrected sp
###############################################################################
uieh_cont:
clr.b SPCOND_FLG(%a6) # clear "special case" flag
mov.w EXC_ISR(%a6),EXC_CC(%a6) # store cc copy on stack
mov.l EXC_IPC(%a6),EXC_EXTWPTR(%a6) # store extwptr on stack
#
# fetch the opword and first extension word pointed to by the stacked pc
# and store them to the stack for now
#
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x4,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_long # fetch opword & extword
mov.l %d0,EXC_OPWORD(%a6) # store extword on stack
#########################################################################
# muls.l 0100 1100 00 |<ea>| 0*** 1100 0000 0*** #
# mulu.l 0100 1100 00 |<ea>| 0*** 0100 0000 0*** #
# #
# divs.l 0100 1100 01 |<ea>| 0*** 1100 0000 0*** #
# divu.l 0100 1100 01 |<ea>| 0*** 0100 0000 0*** #
# #
# movep.w m2r 0000 ***1 00 001*** | <displacement> | #
# movep.l m2r 0000 ***1 01 001*** | <displacement> | #
# movep.w r2m 0000 ***1 10 001*** | <displacement> | #
# movep.l r2m 0000 ***1 11 001*** | <displacement> | #
# #
# cas.w 0000 1100 11 |<ea>| 0000 000* **00 0*** #
# cas.l 0000 1110 11 |<ea>| 0000 000* **00 0*** #
# #
# cas2.w 0000 1100 11 111100 **** 000* **00 0*** #
# **** 000* **00 0*** #
# cas2.l 0000 1110 11 111100 **** 000* **00 0*** #
# **** 000* **00 0*** #
# #
# chk2.b 0000 0000 11 |<ea>| **** 1000 0000 0000 #
# chk2.w 0000 0010 11 |<ea>| **** 1000 0000 0000 #
# chk2.l 0000 0100 11 |<ea>| **** 1000 0000 0000 #
# #
# cmp2.b 0000 0000 11 |<ea>| **** 0000 0000 0000 #
# cmp2.w 0000 0010 11 |<ea>| **** 0000 0000 0000 #
# cmp2.l 0000 0100 11 |<ea>| **** 0000 0000 0000 #
#########################################################################
#
# using bit 14 of the operation word, separate into 2 groups:
# (group1) mul64, div64
# (group2) movep, chk2, cmp2, cas2, cas
#
btst &0x1e,%d0 # group1 or group2
beq.b uieh_group2 # go handle group2
#
# now, w/ group1, make mul64's decode the fastest since it will
# most likely be used the most.
#
uieh_group1:
btst &0x16,%d0 # test for div64
bne.b uieh_div64 # go handle div64
uieh_mul64:
# mul64() may use ()+ addressing and may, therefore, alter a7
bsr.l _mul64 # _mul64()
btst &0x5,EXC_ISR(%a6) # supervisor mode?
beq.w uieh_done
btst &mia7_bit,SPCOND_FLG(%a6) # was a7 changed?
beq.w uieh_done # no
btst &0x7,EXC_ISR(%a6) # is trace enabled?
bne.w uieh_trace_a7 # yes
bra.w uieh_a7 # no
uieh_div64:
# div64() may use ()+ addressing and may, therefore, alter a7.
# div64() may take a divide by zero exception.
bsr.l _div64 # _div64()
# here, we sort out all of the special cases that may have happened.
btst &mia7_bit,SPCOND_FLG(%a6) # was a7 changed?
bne.b uieh_div64_a7 # yes
uieh_div64_dbyz:
btst &idbyz_bit,SPCOND_FLG(%a6) # did divide-by-zero occur?
bne.w uieh_divbyzero # yes
bra.w uieh_done # no
uieh_div64_a7:
btst &0x5,EXC_ISR(%a6) # supervisor mode?
beq.b uieh_div64_dbyz # no
# here, a7 has been incremented by 4 bytes in supervisor mode. we still
# may have the following 3 cases:
# (i) (a7)+
# (ii) (a7)+; trace
# (iii) (a7)+; divide-by-zero
#
btst &idbyz_bit,SPCOND_FLG(%a6) # did divide-by-zero occur?
bne.w uieh_divbyzero_a7 # yes
tst.b EXC_ISR(%a6) # no; is trace enabled?
bmi.w uieh_trace_a7 # yes
bra.w uieh_a7 # no
#
# now, w/ group2, make movep's decode the fastest since it will
# most likely be used the most.
#
uieh_group2:
btst &0x18,%d0 # test for not movep
beq.b uieh_not_movep
bsr.l _moveperipheral # _movep()
bra.w uieh_done
uieh_not_movep:
btst &0x1b,%d0 # test for chk2,cmp2
beq.b uieh_chk2cmp2 # go handle chk2,cmp2
swap %d0 # put opword in lo word
cmpi.b %d0,&0xfc # test for cas2
beq.b uieh_cas2 # go handle cas2
uieh_cas:
bsr.l _compandset # _cas()
# the cases of "cas Dc,Du,(a7)+" and "cas Dc,Du,-(a7)" used from supervisor
# mode are simply not considered valid and therefore are not handled.
bra.w uieh_done
uieh_cas2:
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x2,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_word # read extension word
tst.l %d1 # ifetch error?
bne.w isp_iacc # yes
bsr.l _compandset2 # _cas2()
bra.w uieh_done
uieh_chk2cmp2:
# chk2 may take a chk exception
bsr.l _chk2_cmp2 # _chk2_cmp2()
# here we check to see if a chk trap should be taken
cmpi.b SPCOND_FLG(%a6),&ichk_flg
bne.w uieh_done
bra.b uieh_chk_trap
###########################################################################
#
# the required emulation has been completed. now, clean up the necessary stack
# info and prepare for rte
#
uieh_done:
mov.b EXC_CC+1(%a6),EXC_ISR+1(%a6) # insert new ccodes
# if exception occurred in user mode, then we have to restore a7 in case it
# changed. we don't have to update a7 for supervisor mose because that case
# doesn't flow through here
btst &0x5,EXC_ISR(%a6) # user or supervisor?
bne.b uieh_finish # supervisor
mov.l EXC_A7(%a6),%a0 # fetch user stack pointer
mov.l %a0,%usp # restore it
uieh_finish:
movm.l EXC_DREGS(%a6),&0x3fff # restore d0-d7/a0-a5
btst &0x7,EXC_ISR(%a6) # is trace mode on?
bne.b uieh_trace # yes;go handle trace mode
mov.l EXC_EXTWPTR(%a6),EXC_IPC(%a6) # new pc on stack frame
mov.l EXC_A6(%a6),(%a6) # prepare new a6 for unlink
unlk %a6 # unlink stack frame
bra.l _isp_done
#
# The instruction that was just emulated was also being traced. The trace
# trap for this instruction will be lost unless we jump to the trace handler.
# So, here we create a Trace Exception format number two exception stack
# frame from the Unimplemented Integer Intruction Exception stack frame
# format number zero and jump to the user supplied hook "_real_trace()".
#
# UIEH FRAME TRACE FRAME
# ***************** *****************
# * 0x0 * 0x0f4 * * Current *
# ***************** * PC *
# * Current * *****************
# * PC * * 0x2 * 0x024 *
# ***************** *****************
# * SR * * Next *
# ***************** * PC *
# ->* Old * *****************
# from link -->* A6 * * SR *
# ***************** *****************
# /* A7 * * New * <-- for final unlink
# / * * * A6 *
# link frame < ***************** *****************
# \ ~ ~ ~ ~
# \***************** *****************
#
uieh_trace:
mov.l EXC_A6(%a6),-0x4(%a6)
mov.w EXC_ISR(%a6),0x0(%a6)
mov.l EXC_IPC(%a6),0x8(%a6)
mov.l EXC_EXTWPTR(%a6),0x2(%a6)
mov.w &0x2024,0x6(%a6)
sub.l &0x4,%a6
unlk %a6
bra.l _real_trace
#
# UIEH FRAME CHK FRAME
# ***************** *****************
# * 0x0 * 0x0f4 * * Current *
# ***************** * PC *
# * Current * *****************
# * PC * * 0x2 * 0x018 *
# ***************** *****************
# * SR * * Next *
# ***************** * PC *
# (4 words) *****************
# * SR *
# *****************
# (6 words)
#
# the chk2 instruction should take a chk trap. so, here we must create a
# chk stack frame from an unimplemented integer instruction exception frame
# and jump to the user supplied entry point "_real_chk()".
#
uieh_chk_trap:
mov.b EXC_CC+1(%a6),EXC_ISR+1(%a6) # insert new ccodes
movm.l EXC_DREGS(%a6),&0x3fff # restore d0-d7/a0-a5
mov.w EXC_ISR(%a6),(%a6) # put new SR on stack
mov.l EXC_IPC(%a6),0x8(%a6) # put "Current PC" on stack
mov.l EXC_EXTWPTR(%a6),0x2(%a6) # put "Next PC" on stack
mov.w &0x2018,0x6(%a6) # put Vector Offset on stack
mov.l EXC_A6(%a6),%a6 # restore a6
add.l &LOCAL_SIZE,%sp # clear stack frame
bra.l _real_chk
#
# UIEH FRAME DIVBYZERO FRAME
# ***************** *****************
# * 0x0 * 0x0f4 * * Current *
# ***************** * PC *
# * Current * *****************
# * PC * * 0x2 * 0x014 *
# ***************** *****************
# * SR * * Next *
# ***************** * PC *
# (4 words) *****************
# * SR *
# *****************
# (6 words)
#
# the divide instruction should take an integer divide by zero trap. so, here
# we must create a divbyzero stack frame from an unimplemented integer
# instruction exception frame and jump to the user supplied entry point
# "_real_divbyzero()".
#
uieh_divbyzero:
mov.b EXC_CC+1(%a6),EXC_ISR+1(%a6) # insert new ccodes
movm.l EXC_DREGS(%a6),&0x3fff # restore d0-d7/a0-a5
mov.w EXC_ISR(%a6),(%a6) # put new SR on stack
mov.l EXC_IPC(%a6),0x8(%a6) # put "Current PC" on stack
mov.l EXC_EXTWPTR(%a6),0x2(%a6) # put "Next PC" on stack
mov.w &0x2014,0x6(%a6) # put Vector Offset on stack
mov.l EXC_A6(%a6),%a6 # restore a6
add.l &LOCAL_SIZE,%sp # clear stack frame
bra.l _real_divbyzero
#
# DIVBYZERO FRAME
# *****************
# * Current *
# UIEH FRAME * PC *
# ***************** *****************
# * 0x0 * 0x0f4 * * 0x2 * 0x014 *
# ***************** *****************
# * Current * * Next *
# * PC * * PC *
# ***************** *****************
# * SR * * SR *
# ***************** *****************
# (4 words) (6 words)
#
# the divide instruction should take an integer divide by zero trap. so, here
# we must create a divbyzero stack frame from an unimplemented integer
# instruction exception frame and jump to the user supplied entry point
# "_real_divbyzero()".
#
# However, we must also deal with the fact that (a7)+ was used from supervisor
# mode, thereby shifting the stack frame up 4 bytes.
#
uieh_divbyzero_a7:
mov.b EXC_CC+1(%a6),EXC_ISR+1(%a6) # insert new ccodes
movm.l EXC_DREGS(%a6),&0x3fff # restore d0-d7/a0-a5
mov.l EXC_IPC(%a6),0xc(%a6) # put "Current PC" on stack
mov.w &0x2014,0xa(%a6) # put Vector Offset on stack
mov.l EXC_EXTWPTR(%a6),0x6(%a6) # put "Next PC" on stack
mov.l EXC_A6(%a6),%a6 # restore a6
add.l &4+LOCAL_SIZE,%sp # clear stack frame
bra.l _real_divbyzero
#
# TRACE FRAME
# *****************
# * Current *
# UIEH FRAME * PC *
# ***************** *****************
# * 0x0 * 0x0f4 * * 0x2 * 0x024 *
# ***************** *****************
# * Current * * Next *
# * PC * * PC *
# ***************** *****************
# * SR * * SR *
# ***************** *****************
# (4 words) (6 words)
#
#
# The instruction that was just emulated was also being traced. The trace
# trap for this instruction will be lost unless we jump to the trace handler.
# So, here we create a Trace Exception format number two exception stack
# frame from the Unimplemented Integer Intruction Exception stack frame
# format number zero and jump to the user supplied hook "_real_trace()".
#
# However, we must also deal with the fact that (a7)+ was used from supervisor
# mode, thereby shifting the stack frame up 4 bytes.
#
uieh_trace_a7:
mov.b EXC_CC+1(%a6),EXC_ISR+1(%a6) # insert new ccodes
movm.l EXC_DREGS(%a6),&0x3fff # restore d0-d7/a0-a5
mov.l EXC_IPC(%a6),0xc(%a6) # put "Current PC" on stack
mov.w &0x2024,0xa(%a6) # put Vector Offset on stack
mov.l EXC_EXTWPTR(%a6),0x6(%a6) # put "Next PC" on stack
mov.l EXC_A6(%a6),%a6 # restore a6
add.l &4+LOCAL_SIZE,%sp # clear stack frame
bra.l _real_trace
#
# UIEH FRAME
# *****************
# * 0x0 * 0x0f4 *
# UIEH FRAME *****************
# ***************** * Next *
# * 0x0 * 0x0f4 * * PC *
# ***************** *****************
# * Current * * SR *
# * PC * *****************
# ***************** (4 words)
# * SR *
# *****************
# (4 words)
uieh_a7:
mov.b EXC_CC+1(%a6),EXC_ISR+1(%a6) # insert new ccodes
movm.l EXC_DREGS(%a6),&0x3fff # restore d0-d7/a0-a5
mov.w &0x00f4,0xe(%a6) # put Vector Offset on stack
mov.l EXC_EXTWPTR(%a6),0xa(%a6) # put "Next PC" on stack
mov.w EXC_ISR(%a6),0x8(%a6) # put SR on stack
mov.l EXC_A6(%a6),%a6 # restore a6
add.l &8+LOCAL_SIZE,%sp # clear stack frame
bra.l _isp_done
##########
# this is the exit point if a data read or write fails.
# a0 = failing address
# d0 = fslw
isp_dacc:
mov.l %a0,(%a6) # save address
mov.l %d0,-0x4(%a6) # save partial fslw
lea -64(%a6),%sp
movm.l (%sp)+,&0x7fff # restore d0-d7/a0-a6
mov.l 0xc(%sp),-(%sp) # move voff,hi(pc)
mov.l 0x4(%sp),0x10(%sp) # store fslw
mov.l 0xc(%sp),0x4(%sp) # store sr,lo(pc)
mov.l 0x8(%sp),0xc(%sp) # store address
mov.l (%sp)+,0x4(%sp) # store voff,hi(pc)
mov.w &0x4008,0x6(%sp) # store new voff
bra.b isp_acc_exit
# this is the exit point if an instruction word read fails.
# FSLW:
# misaligned = true
# read = true
# size = word
# instruction = true
# software emulation error = true
isp_iacc:
movm.l EXC_DREGS(%a6),&0x3fff # restore d0-d7/a0-a5
unlk %a6 # unlink frame
sub.w &0x8,%sp # make room for acc frame
mov.l 0x8(%sp),(%sp) # store sr,lo(pc)
mov.w 0xc(%sp),0x4(%sp) # store hi(pc)
mov.w &0x4008,0x6(%sp) # store new voff
mov.l 0x2(%sp),0x8(%sp) # store address (=pc)
mov.l &0x09428001,0xc(%sp) # store fslw
isp_acc_exit:
btst &0x5,(%sp) # user or supervisor?
beq.b isp_acc_exit2 # user
bset &0x2,0xd(%sp) # set supervisor TM bit
isp_acc_exit2:
bra.l _real_access
# if the addressing mode was (an)+ or -(an), the address register must
# be restored to its pre-exception value before entering _real_access.
isp_restore:
cmpi.b SPCOND_FLG(%a6),&restore_flg # do we need a restore?
bne.b isp_restore_done # no
clr.l %d0
mov.b EXC_SAVREG(%a6),%d0 # regno to restore
mov.l EXC_SAVVAL(%a6),(EXC_AREGS,%a6,%d0.l*4) # restore value
isp_restore_done:
rts
#########################################################################
# XDEF **************************************************************** #
# _calc_ea(): routine to calculate effective address #
# #
# XREF **************************************************************** #
# _imem_read_word() - read instruction word #
# _imem_read_long() - read instruction longword #
# _dmem_read_long() - read data longword (for memory indirect) #
# isp_iacc() - handle instruction access error exception #
# isp_dacc() - handle data access error exception #
# #
# INPUT *************************************************************** #
# d0 = number of bytes related to effective address (w,l) #
# #
# OUTPUT ************************************************************** #
# If exiting through isp_dacc... #
# a0 = failing address #
# d0 = FSLW #
# elsif exiting though isp_iacc... #
# none #
# else #
# a0 = effective address #
# #
# ALGORITHM *********************************************************** #
# The effective address type is decoded from the opword residing #
# on the stack. A jump table is used to vector to a routine for the #
# appropriate mode. Since none of the emulated integer instructions #
# uses byte-sized operands, only handle word and long operations. #
# #
# Dn,An - shouldn't enter here #
# (An) - fetch An value from stack #
# -(An) - fetch An value from stack; return decr value; #
# place decr value on stack; store old value in case of #
# future access error; if -(a7), set mda7_flg in #
# SPCOND_FLG #
# (An)+ - fetch An value from stack; return value; #
# place incr value on stack; store old value in case of #
# future access error; if (a7)+, set mia7_flg in #
# SPCOND_FLG #
# (d16,An) - fetch An value from stack; read d16 using #
# _imem_read_word(); fetch may fail -> branch to #
# isp_iacc() #
# (xxx).w,(xxx).l - use _imem_read_{word,long}() to fetch #
# address; fetch may fail #
# #<data> - return address of immediate value; set immed_flg #
# in SPCOND_FLG #
# (d16,PC) - fetch stacked PC value; read d16 using #
# _imem_read_word(); fetch may fail -> branch to #
# isp_iacc() #
# everything else - read needed displacements as appropriate w/ #
# _imem_read_{word,long}(); read may fail; if memory #
# indirect, read indirect address using #
# _dmem_read_long() which may also fail #
# #
#########################################################################
global _calc_ea
_calc_ea:
mov.l %d0,%a0 # move # bytes to a0
# MODE and REG are taken from the EXC_OPWORD.
mov.w EXC_OPWORD(%a6),%d0 # fetch opcode word
mov.w %d0,%d1 # make a copy
andi.w &0x3f,%d0 # extract mode field
andi.l &0x7,%d1 # extract reg field
# jump to the corresponding function for each {MODE,REG} pair.
mov.w (tbl_ea_mode.b,%pc,%d0.w*2), %d0 # fetch jmp distance
jmp (tbl_ea_mode.b,%pc,%d0.w*1) # jmp to correct ea mode
swbeg &64
tbl_ea_mode:
short tbl_ea_mode - tbl_ea_mode
short tbl_ea_mode - tbl_ea_mode
short tbl_ea_mode - tbl_ea_mode
short tbl_ea_mode - tbl_ea_mode
short tbl_ea_mode - tbl_ea_mode
short tbl_ea_mode - tbl_ea_mode
short tbl_ea_mode - tbl_ea_mode
short tbl_ea_mode - tbl_ea_mode
short tbl_ea_mode - tbl_ea_mode
short tbl_ea_mode - tbl_ea_mode
short tbl_ea_mode - tbl_ea_mode
short tbl_ea_mode - tbl_ea_mode
short tbl_ea_mode - tbl_ea_mode
short tbl_ea_mode - tbl_ea_mode
short tbl_ea_mode - tbl_ea_mode
short tbl_ea_mode - tbl_ea_mode
short addr_ind_a0 - tbl_ea_mode
short addr_ind_a1 - tbl_ea_mode
short addr_ind_a2 - tbl_ea_mode
short addr_ind_a3 - tbl_ea_mode
short addr_ind_a4 - tbl_ea_mode
short addr_ind_a5 - tbl_ea_mode
short addr_ind_a6 - tbl_ea_mode
short addr_ind_a7 - tbl_ea_mode
short addr_ind_p_a0 - tbl_ea_mode
short addr_ind_p_a1 - tbl_ea_mode
short addr_ind_p_a2 - tbl_ea_mode
short addr_ind_p_a3 - tbl_ea_mode
short addr_ind_p_a4 - tbl_ea_mode
short addr_ind_p_a5 - tbl_ea_mode
short addr_ind_p_a6 - tbl_ea_mode
short addr_ind_p_a7 - tbl_ea_mode
short addr_ind_m_a0 - tbl_ea_mode
short addr_ind_m_a1 - tbl_ea_mode
short addr_ind_m_a2 - tbl_ea_mode
short addr_ind_m_a3 - tbl_ea_mode
short addr_ind_m_a4 - tbl_ea_mode
short addr_ind_m_a5 - tbl_ea_mode
short addr_ind_m_a6 - tbl_ea_mode
short addr_ind_m_a7 - tbl_ea_mode
short addr_ind_disp_a0 - tbl_ea_mode
short addr_ind_disp_a1 - tbl_ea_mode
short addr_ind_disp_a2 - tbl_ea_mode
short addr_ind_disp_a3 - tbl_ea_mode
short addr_ind_disp_a4 - tbl_ea_mode
short addr_ind_disp_a5 - tbl_ea_mode
short addr_ind_disp_a6 - tbl_ea_mode
short addr_ind_disp_a7 - tbl_ea_mode
short _addr_ind_ext - tbl_ea_mode
short _addr_ind_ext - tbl_ea_mode
short _addr_ind_ext - tbl_ea_mode
short _addr_ind_ext - tbl_ea_mode
short _addr_ind_ext - tbl_ea_mode
short _addr_ind_ext - tbl_ea_mode
short _addr_ind_ext - tbl_ea_mode
short _addr_ind_ext - tbl_ea_mode
short abs_short - tbl_ea_mode
short abs_long - tbl_ea_mode
short pc_ind - tbl_ea_mode
short pc_ind_ext - tbl_ea_mode
short immediate - tbl_ea_mode
short tbl_ea_mode - tbl_ea_mode
short tbl_ea_mode - tbl_ea_mode
short tbl_ea_mode - tbl_ea_mode
###################################
# Address register indirect: (An) #
###################################
addr_ind_a0:
mov.l EXC_A0(%a6),%a0 # Get current a0
rts
addr_ind_a1:
mov.l EXC_A1(%a6),%a0 # Get current a1
rts
addr_ind_a2:
mov.l EXC_A2(%a6),%a0 # Get current a2
rts
addr_ind_a3:
mov.l EXC_A3(%a6),%a0 # Get current a3
rts
addr_ind_a4:
mov.l EXC_A4(%a6),%a0 # Get current a4
rts
addr_ind_a5:
mov.l EXC_A5(%a6),%a0 # Get current a5
rts
addr_ind_a6:
mov.l EXC_A6(%a6),%a0 # Get current a6
rts
addr_ind_a7:
mov.l EXC_A7(%a6),%a0 # Get current a7
rts
#####################################################
# Address register indirect w/ postincrement: (An)+ #
#####################################################
addr_ind_p_a0:
mov.l %a0,%d0 # copy no. bytes
mov.l EXC_A0(%a6),%a0 # load current value
add.l %a0,%d0 # increment
mov.l %d0,EXC_A0(%a6) # save incremented value
mov.l %a0,EXC_SAVVAL(%a6) # save in case of access error
mov.b &0x0,EXC_SAVREG(%a6) # save regno, too
mov.b &restore_flg,SPCOND_FLG(%a6) # set flag
rts
addr_ind_p_a1:
mov.l %a0,%d0 # copy no. bytes
mov.l EXC_A1(%a6),%a0 # load current value
add.l %a0,%d0 # increment
mov.l %d0,EXC_A1(%a6) # save incremented value
mov.l %a0,EXC_SAVVAL(%a6) # save in case of access error
mov.b &0x1,EXC_SAVREG(%a6) # save regno, too
mov.b &restore_flg,SPCOND_FLG(%a6) # set flag
rts
addr_ind_p_a2:
mov.l %a0,%d0 # copy no. bytes
mov.l EXC_A2(%a6),%a0 # load current value
add.l %a0,%d0 # increment
mov.l %d0,EXC_A2(%a6) # save incremented value
mov.l %a0,EXC_SAVVAL(%a6) # save in case of access error
mov.b &0x2,EXC_SAVREG(%a6) # save regno, too
mov.b &restore_flg,SPCOND_FLG(%a6) # set flag
rts
addr_ind_p_a3:
mov.l %a0,%d0 # copy no. bytes
mov.l EXC_A3(%a6),%a0 # load current value
add.l %a0,%d0 # increment
mov.l %d0,EXC_A3(%a6) # save incremented value
mov.l %a0,EXC_SAVVAL(%a6) # save in case of access error
mov.b &0x3,EXC_SAVREG(%a6) # save regno, too
mov.b &restore_flg,SPCOND_FLG(%a6) # set flag
rts
addr_ind_p_a4:
mov.l %a0,%d0 # copy no. bytes
mov.l EXC_A4(%a6),%a0 # load current value
add.l %a0,%d0 # increment
mov.l %d0,EXC_A4(%a6) # save incremented value
mov.l %a0,EXC_SAVVAL(%a6) # save in case of access error
mov.b &0x4,EXC_SAVREG(%a6) # save regno, too
mov.b &restore_flg,SPCOND_FLG(%a6) # set flag
rts
addr_ind_p_a5:
mov.l %a0,%d0 # copy no. bytes
mov.l EXC_A5(%a6),%a0 # load current value
add.l %a0,%d0 # increment
mov.l %d0,EXC_A5(%a6) # save incremented value
mov.l %a0,EXC_SAVVAL(%a6) # save in case of access error
mov.b &0x5,EXC_SAVREG(%a6) # save regno, too
mov.b &restore_flg,SPCOND_FLG(%a6) # set flag
rts
addr_ind_p_a6:
mov.l %a0,%d0 # copy no. bytes
mov.l EXC_A6(%a6),%a0 # load current value
add.l %a0,%d0 # increment
mov.l %d0,EXC_A6(%a6) # save incremented value
mov.l %a0,EXC_SAVVAL(%a6) # save in case of access error
mov.b &0x6,EXC_SAVREG(%a6) # save regno, too
mov.b &restore_flg,SPCOND_FLG(%a6) # set flag
rts
addr_ind_p_a7:
mov.b &mia7_flg,SPCOND_FLG(%a6) # set "special case" flag
mov.l %a0,%d0 # copy no. bytes
mov.l EXC_A7(%a6),%a0 # load current value
add.l %a0,%d0 # increment
mov.l %d0,EXC_A7(%a6) # save incremented value
rts
####################################################
# Address register indirect w/ predecrement: -(An) #
####################################################
addr_ind_m_a0:
mov.l EXC_A0(%a6),%d0 # Get current a0
mov.l %d0,EXC_SAVVAL(%a6) # save in case of access error
sub.l %a0,%d0 # Decrement
mov.l %d0,EXC_A0(%a6) # Save decr value
mov.l %d0,%a0
mov.b &0x0,EXC_SAVREG(%a6) # save regno, too
mov.b &restore_flg,SPCOND_FLG(%a6) # set flag
rts
addr_ind_m_a1:
mov.l EXC_A1(%a6),%d0 # Get current a1
mov.l %d0,EXC_SAVVAL(%a6) # save in case of access error
sub.l %a0,%d0 # Decrement
mov.l %d0,EXC_A1(%a6) # Save decr value
mov.l %d0,%a0
mov.b &0x1,EXC_SAVREG(%a6) # save regno, too
mov.b &restore_flg,SPCOND_FLG(%a6) # set flag
rts
addr_ind_m_a2:
mov.l EXC_A2(%a6),%d0 # Get current a2
mov.l %d0,EXC_SAVVAL(%a6) # save in case of access error
sub.l %a0,%d0 # Decrement
mov.l %d0,EXC_A2(%a6) # Save decr value
mov.l %d0,%a0
mov.b &0x2,EXC_SAVREG(%a6) # save regno, too
mov.b &restore_flg,SPCOND_FLG(%a6) # set flag
rts
addr_ind_m_a3:
mov.l EXC_A3(%a6),%d0 # Get current a3
mov.l %d0,EXC_SAVVAL(%a6) # save in case of access error
sub.l %a0,%d0 # Decrement
mov.l %d0,EXC_A3(%a6) # Save decr value
mov.l %d0,%a0
mov.b &0x3,EXC_SAVREG(%a6) # save regno, too
mov.b &restore_flg,SPCOND_FLG(%a6) # set flag
rts
addr_ind_m_a4:
mov.l EXC_A4(%a6),%d0 # Get current a4
mov.l %d0,EXC_SAVVAL(%a6) # save in case of access error
sub.l %a0,%d0 # Decrement
mov.l %d0,EXC_A4(%a6) # Save decr value
mov.l %d0,%a0
mov.b &0x4,EXC_SAVREG(%a6) # save regno, too
mov.b &restore_flg,SPCOND_FLG(%a6) # set flag
rts
addr_ind_m_a5:
mov.l EXC_A5(%a6),%d0 # Get current a5
mov.l %d0,EXC_SAVVAL(%a6) # save in case of access error
sub.l %a0,%d0 # Decrement
mov.l %d0,EXC_A5(%a6) # Save decr value
mov.l %d0,%a0
mov.b &0x5,EXC_SAVREG(%a6) # save regno, too
mov.b &restore_flg,SPCOND_FLG(%a6) # set flag
rts
addr_ind_m_a6:
mov.l EXC_A6(%a6),%d0 # Get current a6
mov.l %d0,EXC_SAVVAL(%a6) # save in case of access error
sub.l %a0,%d0 # Decrement
mov.l %d0,EXC_A6(%a6) # Save decr value
mov.l %d0,%a0
mov.b &0x6,EXC_SAVREG(%a6) # save regno, too
mov.b &restore_flg,SPCOND_FLG(%a6) # set flag
rts
addr_ind_m_a7:
mov.b &mda7_flg,SPCOND_FLG(%a6) # set "special case" flag
mov.l EXC_A7(%a6),%d0 # Get current a7
sub.l %a0,%d0 # Decrement
mov.l %d0,EXC_A7(%a6) # Save decr value
mov.l %d0,%a0
rts
########################################################
# Address register indirect w/ displacement: (d16, An) #
########################################################
addr_ind_disp_a0:
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x2,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_word
tst.l %d1 # ifetch error?
bne.l isp_iacc # yes
mov.w %d0,%a0 # sign extend displacement
add.l EXC_A0(%a6),%a0 # a0 + d16
rts
addr_ind_disp_a1:
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x2,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_word
tst.l %d1 # ifetch error?
bne.l isp_iacc # yes
mov.w %d0,%a0 # sign extend displacement
add.l EXC_A1(%a6),%a0 # a1 + d16
rts
addr_ind_disp_a2:
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x2,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_word
tst.l %d1 # ifetch error?
bne.l isp_iacc # yes
mov.w %d0,%a0 # sign extend displacement
add.l EXC_A2(%a6),%a0 # a2 + d16
rts
addr_ind_disp_a3:
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x2,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_word
tst.l %d1 # ifetch error?
bne.l isp_iacc # yes
mov.w %d0,%a0 # sign extend displacement
add.l EXC_A3(%a6),%a0 # a3 + d16
rts
addr_ind_disp_a4:
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x2,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_word
tst.l %d1 # ifetch error?
bne.l isp_iacc # yes
mov.w %d0,%a0 # sign extend displacement
add.l EXC_A4(%a6),%a0 # a4 + d16
rts
addr_ind_disp_a5:
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x2,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_word
tst.l %d1 # ifetch error?
bne.l isp_iacc # yes
mov.w %d0,%a0 # sign extend displacement
add.l EXC_A5(%a6),%a0 # a5 + d16
rts
addr_ind_disp_a6:
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x2,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_word
tst.l %d1 # ifetch error?
bne.l isp_iacc # yes
mov.w %d0,%a0 # sign extend displacement
add.l EXC_A6(%a6),%a0 # a6 + d16
rts
addr_ind_disp_a7:
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x2,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_word
tst.l %d1 # ifetch error?
bne.l isp_iacc # yes
mov.w %d0,%a0 # sign extend displacement
add.l EXC_A7(%a6),%a0 # a7 + d16
rts
########################################################################
# Address register indirect w/ index(8-bit displacement): (dn, An, Xn) #
# " " " w/ " (base displacement): (bd, An, Xn) #
# Memory indirect postindexed: ([bd, An], Xn, od) #
# Memory indirect preindexed: ([bd, An, Xn], od) #
########################################################################
_addr_ind_ext:
mov.l %d1,-(%sp)
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x2,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_word # fetch extword in d0
tst.l %d1 # ifetch error?
bne.l isp_iacc # yes
mov.l (%sp)+,%d1
mov.l (EXC_AREGS,%a6,%d1.w*4),%a0 # put base in a0
btst &0x8,%d0
beq.b addr_ind_index_8bit # for ext word or not?
movm.l &0x3c00,-(%sp) # save d2-d5
mov.l %d0,%d5 # put extword in d5
mov.l %a0,%d3 # put base in d3
bra.l calc_mem_ind # calc memory indirect
addr_ind_index_8bit:
mov.l %d2,-(%sp) # save old d2
mov.l %d0,%d1
rol.w &0x4,%d1
andi.w &0xf,%d1 # extract index regno
mov.l (EXC_DREGS,%a6,%d1.w*4),%d1 # fetch index reg value
btst &0xb,%d0 # is it word or long?
bne.b aii8_long
ext.l %d1 # sign extend word index
aii8_long:
mov.l %d0,%d2
rol.w &0x7,%d2
andi.l &0x3,%d2 # extract scale value
lsl.l %d2,%d1 # shift index by scale
extb.l %d0 # sign extend displacement
add.l %d1,%d0 # index + disp
add.l %d0,%a0 # An + (index + disp)
mov.l (%sp)+,%d2 # restore old d2
rts
######################
# Immediate: #<data> #
#########################################################################
# word, long: <ea> of the data is the current extension word #
# pointer value. new extension word pointer is simply the old #
# plus the number of bytes in the data type(2 or 4). #
#########################################################################
immediate:
mov.b &immed_flg,SPCOND_FLG(%a6) # set immediate flag
mov.l EXC_EXTWPTR(%a6),%a0 # fetch extension word ptr
rts
###########################
# Absolute short: (XXX).W #
###########################
abs_short:
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x2,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_word # fetch short address
tst.l %d1 # ifetch error?
bne.l isp_iacc # yes
mov.w %d0,%a0 # return <ea> in a0
rts
##########################
# Absolute long: (XXX).L #
##########################
abs_long:
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x4,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_long # fetch long address
tst.l %d1 # ifetch error?
bne.l isp_iacc # yes
mov.l %d0,%a0 # return <ea> in a0
rts
#######################################################
# Program counter indirect w/ displacement: (d16, PC) #
#######################################################
pc_ind:
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x2,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_word # fetch word displacement
tst.l %d1 # ifetch error?
bne.l isp_iacc # yes
mov.w %d0,%a0 # sign extend displacement
add.l EXC_EXTWPTR(%a6),%a0 # pc + d16
# _imem_read_word() increased the extwptr by 2. need to adjust here.
subq.l &0x2,%a0 # adjust <ea>
rts
##########################################################
# PC indirect w/ index(8-bit displacement): (d8, PC, An) #
# " " w/ " (base displacement): (bd, PC, An) #
# PC memory indirect postindexed: ([bd, PC], Xn, od) #
# PC memory indirect preindexed: ([bd, PC, Xn], od) #
##########################################################
pc_ind_ext:
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x2,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_word # fetch ext word
tst.l %d1 # ifetch error?
bne.l isp_iacc # yes
mov.l EXC_EXTWPTR(%a6),%a0 # put base in a0
subq.l &0x2,%a0 # adjust base
btst &0x8,%d0 # is disp only 8 bits?
beq.b pc_ind_index_8bit # yes
# the indexed addressing mode uses a base displacement of size
# word or long
movm.l &0x3c00,-(%sp) # save d2-d5
mov.l %d0,%d5 # put extword in d5
mov.l %a0,%d3 # put base in d3
bra.l calc_mem_ind # calc memory indirect
pc_ind_index_8bit:
mov.l %d2,-(%sp) # create a temp register
mov.l %d0,%d1 # make extword copy
rol.w &0x4,%d1 # rotate reg num into place
andi.w &0xf,%d1 # extract register number
mov.l (EXC_DREGS,%a6,%d1.w*4),%d1 # fetch index reg value
btst &0xb,%d0 # is index word or long?
bne.b pii8_long # long
ext.l %d1 # sign extend word index
pii8_long:
mov.l %d0,%d2 # make extword copy
rol.w &0x7,%d2 # rotate scale value into place
andi.l &0x3,%d2 # extract scale value
lsl.l %d2,%d1 # shift index by scale
extb.l %d0 # sign extend displacement
add.l %d1,%d0 # index + disp
add.l %d0,%a0 # An + (index + disp)
mov.l (%sp)+,%d2 # restore temp register
rts
# a5 = exc_extwptr (global to uaeh)
# a4 = exc_opword (global to uaeh)
# a3 = exc_dregs (global to uaeh)
# d2 = index (internal " " )
# d3 = base (internal " " )
# d4 = od (internal " " )
# d5 = extword (internal " " )
calc_mem_ind:
btst &0x6,%d5 # is the index suppressed?
beq.b calc_index
clr.l %d2 # yes, so index = 0
bra.b base_supp_ck
calc_index:
bfextu %d5{&16:&4},%d2
mov.l (EXC_DREGS,%a6,%d2.w*4),%d2
btst &0xb,%d5 # is index word or long?
bne.b no_ext
ext.l %d2
no_ext:
bfextu %d5{&21:&2},%d0
lsl.l %d0,%d2
base_supp_ck:
btst &0x7,%d5 # is the bd suppressed?
beq.b no_base_sup
clr.l %d3
no_base_sup:
bfextu %d5{&26:&2},%d0 # get bd size
# beq.l _error # if (size == 0) it's reserved
cmpi.b %d0,&2
blt.b no_bd
beq.b get_word_bd
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x4,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_long
tst.l %d1 # ifetch error?
bne.l isp_iacc # yes
bra.b chk_ind
get_word_bd:
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x2,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_word
tst.l %d1 # ifetch error?
bne.l isp_iacc # yes
ext.l %d0 # sign extend bd
chk_ind:
add.l %d0,%d3 # base += bd
no_bd:
bfextu %d5{&30:&2},%d0 # is od suppressed?
beq.w aii_bd
cmpi.b %d0,&0x2
blt.b null_od
beq.b word_od
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x4,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_long
tst.l %d1 # ifetch error?
bne.l isp_iacc # yes
bra.b add_them
word_od:
mov.l EXC_EXTWPTR(%a6),%a0 # fetch instruction addr
addq.l &0x2,EXC_EXTWPTR(%a6) # incr instruction ptr
bsr.l _imem_read_word
tst.l %d1 # ifetch error?
bne.l isp_iacc # yes
ext.l %d0 # sign extend od
bra.b add_them
null_od:
clr.l %d0
add_them:
mov.l %d0,%d4
btst &0x2,%d5 # pre or post indexing?
beq.b pre_indexed
mov.l %d3,%a0
bsr.l _dmem_read_long
tst.l %d1 # dfetch error?
bne.b calc_ea_err # yes
add.l %d2,%d0 # <ea> += index
add.l %d4,%d0 # <ea> += od
bra.b done_ea
pre_indexed:
add.l %d2,%d3 # preindexing
mov.l %d3,%a0
bsr.l _dmem_read_long
tst.l %d1 # ifetch error?
bne.b calc_ea_err # yes
add.l %d4,%d0 # ea += od
bra.b done_ea
aii_bd:
add.l %d2,%d3 # ea = (base + bd) + index
mov.l %d3,%d0
done_ea:
mov.l %d0,%a0
movm.l (%sp)+,&0x003c # restore d2-d5
rts
# if dmem_read_long() returns a fail message in d1, the package
# must create an access error frame. here, we pass a skeleton fslw
# and the failing address to the routine that creates the new frame.
# FSLW:
# read = true
# size = longword
# TM = data
# software emulation error = true
calc_ea_err:
mov.l %d3,%a0 # pass failing address
mov.l &0x01010001,%d0 # pass fslw
bra.l isp_dacc
#########################################################################
# XDEF **************************************************************** #
# _moveperipheral(): routine to emulate movep instruction #
# #
# XREF **************************************************************** #
# _dmem_read_byte() - read byte from memory #
# _dmem_write_byte() - write byte to memory #
# isp_dacc() - handle data access error exception #
# #
# INPUT *************************************************************** #
# none #
# #
# OUTPUT ************************************************************** #
# If exiting through isp_dacc... #
# a0 = failing address #
# d0 = FSLW #
# else #
# none #
# #
# ALGORITHM *********************************************************** #
# Decode the movep instruction words stored at EXC_OPWORD and #
# either read or write the required bytes from/to memory. Use the #
# _dmem_{read,write}_byte() routines. If one of the memory routines #
# returns a failing value, we must pass the failing address and a FSLW #
# to the _isp_dacc() routine. #
# Since this instruction is used to access peripherals, make sure #
# to only access the required bytes. #
# #
#########################################################################
###########################
# movep.(w,l) Dx,(d,Ay) #
# movep.(w,l) (d,Ay),Dx #
###########################
global _moveperipheral
_moveperipheral:
mov.w EXC_OPWORD(%a6),%d1 # fetch the opcode word
mov.b %d1,%d0
and.w &0x7,%d0 # extract Ay from opcode word
mov.l (EXC_AREGS,%a6,%d0.w*4),%a0 # fetch ay
add.w EXC_EXTWORD(%a6),%a0 # add: an + sgn_ext(disp)
btst &0x7,%d1 # (reg 2 mem) or (mem 2 reg)
beq.w mem2reg
# reg2mem: fetch dx, then write it to memory
reg2mem:
mov.w %d1,%d0
rol.w &0x7,%d0
and.w &0x7,%d0 # extract Dx from opcode word
mov.l (EXC_DREGS,%a6,%d0.w*4), %d0 # fetch dx
btst &0x6,%d1 # word or long operation?
beq.b r2mwtrans
# a0 = dst addr
# d0 = Dx
r2mltrans:
mov.l %d0,%d2 # store data
mov.l %a0,%a2 # store addr
rol.l &0x8,%d2
mov.l %d2,%d0
bsr.l _dmem_write_byte # os : write hi
tst.l %d1 # dfetch error?
bne.w movp_write_err # yes
add.w &0x2,%a2 # incr addr
mov.l %a2,%a0
rol.l &0x8,%d2
mov.l %d2,%d0
bsr.l _dmem_write_byte # os : write lo
tst.l %d1 # dfetch error?
bne.w movp_write_err # yes
add.w &0x2,%a2 # incr addr
mov.l %a2,%a0
rol.l &0x8,%d2
mov.l %d2,%d0
bsr.l _dmem_write_byte # os : write lo
tst.l %d1 # dfetch error?
bne.w movp_write_err # yes
add.w &0x2,%a2 # incr addr
mov.l %a2,%a0
rol.l &0x8,%d2
mov.l %d2,%d0
bsr.l _dmem_write_byte # os : write lo
tst.l %d1 # dfetch error?
bne.w movp_write_err # yes
rts
# a0 = dst addr
# d0 = Dx
r2mwtrans:
mov.l %d0,%d2 # store data
mov.l %a0,%a2 # store addr
lsr.w &0x8,%d0
bsr.l _dmem_write_byte # os : write hi
tst.l %d1 # dfetch error?
bne.w movp_write_err # yes
add.w &0x2,%a2
mov.l %a2,%a0
mov.l %d2,%d0
bsr.l _dmem_write_byte # os : write lo
tst.l %d1 # dfetch error?
bne.w movp_write_err # yes
rts
# mem2reg: read bytes from memory.
# determines the dest register, and then writes the bytes into it.
mem2reg:
btst &0x6,%d1 # word or long operation?
beq.b m2rwtrans
# a0 = dst addr
m2rltrans:
mov.l %a0,%a2 # store addr
bsr.l _dmem_read_byte # read first byte
tst.l %d1 # dfetch error?
bne.w movp_read_err # yes
mov.l %d0,%d2
add.w &0x2,%a2 # incr addr by 2 bytes
mov.l %a2,%a0
bsr.l _dmem_read_byte # read second byte
tst.l %d1 # dfetch error?
bne.w movp_read_err # yes
lsl.w &0x8,%d2
mov.b %d0,%d2 # append bytes
add.w &0x2,%a2 # incr addr by 2 bytes
mov.l %a2,%a0
bsr.l _dmem_read_byte # read second byte
tst.l %d1 # dfetch error?
bne.w movp_read_err # yes
lsl.l &0x8,%d2
mov.b %d0,%d2 # append bytes
add.w &0x2,%a2 # incr addr by 2 bytes
mov.l %a2,%a0
bsr.l _dmem_read_byte # read second byte
tst.l %d1 # dfetch error?
bne.w movp_read_err # yes
lsl.l &0x8,%d2
mov.b %d0,%d2 # append bytes
mov.b EXC_OPWORD(%a6),%d1
lsr.b &0x1,%d1
and.w &0x7,%d1 # extract Dx from opcode word
mov.l %d2,(EXC_DREGS,%a6,%d1.w*4) # store dx
rts
# a0 = dst addr
m2rwtrans:
mov.l %a0,%a2 # store addr
bsr.l _dmem_read_byte # read first byte
tst.l %d1 # dfetch error?
bne.w movp_read_err # yes
mov.l %d0,%d2
add.w &0x2,%a2 # incr addr by 2 bytes
mov.l %a2,%a0
bsr.l _dmem_read_byte # read second byte
tst.l %d1 # dfetch error?
bne.w movp_read_err # yes
lsl.w &0x8,%d2
mov.b %d0,%d2 # append bytes
mov.b EXC_OPWORD(%a6),%d1
lsr.b &0x1,%d1
and.w &0x7,%d1 # extract Dx from opcode word
mov.w %d2,(EXC_DREGS+2,%a6,%d1.w*4) # store dx
rts
# if dmem_{read,write}_byte() returns a fail message in d1, the package
# must create an access error frame. here, we pass a skeleton fslw
# and the failing address to the routine that creates the new frame.
# FSLW:
# write = true
# size = byte
# TM = data
# software emulation error = true
movp_write_err:
mov.l %a2,%a0 # pass failing address
mov.l &0x00a10001,%d0 # pass fslw
bra.l isp_dacc
# FSLW:
# read = true
# size = byte
# TM = data
# software emulation error = true
movp_read_err:
mov.l %a2,%a0 # pass failing address
mov.l &0x01210001,%d0 # pass fslw
bra.l isp_dacc
#########################################################################
# XDEF **************************************************************** #
# _chk2_cmp2(): routine to emulate chk2/cmp2 instructions #
# #
# XREF **************************************************************** #
# _calc_ea(): calculate effective address #
# _dmem_read_long(): read operands #
# _dmem_read_word(): read operands #
# isp_dacc(): handle data access error exception #
# #
# INPUT *************************************************************** #
# none #
# #
# OUTPUT ************************************************************** #
# If exiting through isp_dacc... #
# a0 = failing address #
# d0 = FSLW #
# else #
# none #
# #
# ALGORITHM *********************************************************** #
# First, calculate the effective address, then fetch the byte, #
# word, or longword sized operands. Then, in the interest of #
# simplicity, all operands are converted to longword size whether the #
# operation is byte, word, or long. The bounds are sign extended #
# accordingly. If Rn is a data register, Rn is also sign extended. If #
# Rn is an address register, it need not be sign extended since the #
# full register is always used. #
# The comparisons are made and the condition codes calculated. #
# If the instruction is chk2 and the Rn value is out-of-bounds, set #
# the ichk_flg in SPCOND_FLG. #
# If the memory fetch returns a failing value, pass the failing #
# address and FSLW to the isp_dacc() routine. #
# #
#########################################################################
global _chk2_cmp2
_chk2_cmp2:
# passing size parameter doesn't matter since chk2 & cmp2 can't do
# either predecrement, postincrement, or immediate.
bsr.l _calc_ea # calculate <ea>
mov.b EXC_EXTWORD(%a6), %d0 # fetch hi extension word
rol.b &0x4, %d0 # rotate reg bits into lo
and.w &0xf, %d0 # extract reg bits
mov.l (EXC_DREGS,%a6,%d0.w*4), %d2 # get regval
cmpi.b EXC_OPWORD(%a6), &0x2 # what size is operation?
blt.b chk2_cmp2_byte # size == byte
beq.b chk2_cmp2_word # size == word
# the bounds are longword size. call routine to read the lower
# bound into d0 and the higher bound into d1.
chk2_cmp2_long:
mov.l %a0,%a2 # save copy of <ea>
bsr.l _dmem_read_long # fetch long lower bound
tst.l %d1 # dfetch error?
bne.w chk2_cmp2_err_l # yes
mov.l %d0,%d3 # save long lower bound
addq.l &0x4,%a2
mov.l %a2,%a0 # pass <ea> of long upper bound
bsr.l _dmem_read_long # fetch long upper bound
tst.l %d1 # dfetch error?
bne.w chk2_cmp2_err_l # yes
mov.l %d0,%d1 # long upper bound in d1
mov.l %d3,%d0 # long lower bound in d0
bra.w chk2_cmp2_compare # go do the compare emulation
# the bounds are word size. fetch them in one subroutine call by
# reading a longword. sign extend both. if it's a data operation,
# sign extend Rn to long, also.
chk2_cmp2_word:
mov.l %a0,%a2
bsr.l _dmem_read_long # fetch 2 word bounds
tst.l %d1 # dfetch error?
bne.w chk2_cmp2_err_l # yes
mov.w %d0, %d1 # place hi in %d1
swap %d0 # place lo in %d0
ext.l %d0 # sign extend lo bnd
ext.l %d1 # sign extend hi bnd
btst &0x7, EXC_EXTWORD(%a6) # address compare?
bne.w chk2_cmp2_compare # yes; don't sign extend
# operation is a data register compare.
# sign extend word to long so we can do simple longword compares.
ext.l %d2 # sign extend data word
bra.w chk2_cmp2_compare # go emulate compare
# the bounds are byte size. fetch them in one subroutine call by
# reading a word. sign extend both. if it's a data operation,
# sign extend Rn to long, also.
chk2_cmp2_byte:
mov.l %a0,%a2
bsr.l _dmem_read_word # fetch 2 byte bounds
tst.l %d1 # dfetch error?
bne.w chk2_cmp2_err_w # yes
mov.b %d0, %d1 # place hi in %d1
lsr.w &0x8, %d0 # place lo in %d0
extb.l %d0 # sign extend lo bnd
extb.l %d1 # sign extend hi bnd
btst &0x7, EXC_EXTWORD(%a6) # address compare?
bne.b chk2_cmp2_compare # yes; don't sign extend
# operation is a data register compare.
# sign extend byte to long so we can do simple longword compares.
extb.l %d2 # sign extend data byte
#
# To set the ccodes correctly:
# (1) save 'Z' bit from (Rn - lo)
# (2) save 'Z' and 'N' bits from ((hi - lo) - (Rn - hi))
# (3) keep 'X', 'N', and 'V' from before instruction
# (4) combine ccodes
#
chk2_cmp2_compare:
sub.l %d0, %d2 # (Rn - lo)
mov.w %cc, %d3 # fetch resulting ccodes
andi.b &0x4, %d3 # keep 'Z' bit
sub.l %d0, %d1 # (hi - lo)
cmp.l %d1,%d2 # ((hi - lo) - (Rn - hi))
mov.w %cc, %d4 # fetch resulting ccodes
or.b %d4, %d3 # combine w/ earlier ccodes
andi.b &0x5, %d3 # keep 'Z' and 'N'
mov.w EXC_CC(%a6), %d4 # fetch old ccodes
andi.b &0x1a, %d4 # keep 'X','N','V' bits
or.b %d3, %d4 # insert new ccodes
mov.w %d4, EXC_CC(%a6) # save new ccodes
btst &0x3, EXC_EXTWORD(%a6) # separate chk2,cmp2
bne.b chk2_finish # it's a chk2
rts
# this code handles the only difference between chk2 and cmp2. chk2 would
# have trapped out if the value was out of bounds. we check this by seeing
# if the 'N' bit was set by the operation.
chk2_finish:
btst &0x0, %d4 # is 'N' bit set?
bne.b chk2_trap # yes;chk2 should trap
rts
chk2_trap:
mov.b &ichk_flg,SPCOND_FLG(%a6) # set "special case" flag
rts
# if dmem_read_{long,word}() returns a fail message in d1, the package
# must create an access error frame. here, we pass a skeleton fslw
# and the failing address to the routine that creates the new frame.
# FSLW:
# read = true
# size = longword
# TM = data
# software emulation error = true
chk2_cmp2_err_l:
mov.l %a2,%a0 # pass failing address
mov.l &0x01010001,%d0 # pass fslw
bra.l isp_dacc
# FSLW:
# read = true
# size = word
# TM = data
# software emulation error = true
chk2_cmp2_err_w:
mov.l %a2,%a0 # pass failing address
mov.l &0x01410001,%d0 # pass fslw
bra.l isp_dacc
#########################################################################
# XDEF **************************************************************** #
# _div64(): routine to emulate div{u,s}.l <ea>,Dr:Dq #
# 64/32->32r:32q #
# #
# XREF **************************************************************** #
# _calc_ea() - calculate effective address #
# isp_iacc() - handle instruction access error exception #
# isp_dacc() - handle data access error exception #
# isp_restore() - restore An on access error w/ -() or ()+ #
# #
# INPUT *************************************************************** #
# none #
# #
# OUTPUT ************************************************************** #
# If exiting through isp_dacc... #
# a0 = failing address #
# d0 = FSLW #
# else #
# none #
# #
# ALGORITHM *********************************************************** #
# First, decode the operand location. If it's in Dn, fetch from #
# the stack. If it's in memory, use _calc_ea() to calculate the #
# effective address. Use _dmem_read_long() to fetch at that address. #
# Unless the operand is immediate data. Then use _imem_read_long(). #
# Send failures to isp_dacc() or isp_iacc() as appropriate. #
# If the operands are signed, make them unsigned and save the #
# sign info for later. Separate out special cases like divide-by-zero #
# or 32-bit divides if possible. Else, use a special math algorithm #
# to calculate the result. #
# Restore sign info if signed instruction. Set the condition #
# codes. Set idbyz_flg in SPCOND_FLG if divisor was zero. Store the #
# quotient and remainder in the appropriate data registers on the stack.#
# #
#########################################################################
set NDIVISOR, EXC_TEMP+0x0
set NDIVIDEND, EXC_TEMP+0x1
set NDRSAVE, EXC_TEMP+0x2
set NDQSAVE, EXC_TEMP+0x4
set DDSECOND, EXC_TEMP+0x6
set DDQUOTIENT, EXC_TEMP+0x8
set DDNORMAL, EXC_TEMP+0xc
global _div64
#############
# div(u,s)l #
#############
_div64:
mov.b EXC_OPWORD+1(%a6), %d0
andi.b &0x38, %d0 # extract src mode
bne.w dcontrolmodel_s # %dn dest or control mode?
mov.b EXC_OPWORD+1(%a6), %d0 # extract Dn from opcode
andi.w &0x7, %d0
mov.l (EXC_DREGS,%a6,%d0.w*4), %d7 # fetch divisor from register
dgotsrcl:
beq.w div64eq0 # divisor is = 0!!!
mov.b EXC_EXTWORD+1(%a6), %d0 # extract Dr from extword
mov.b EXC_EXTWORD(%a6), %d1 # extract Dq from extword
and.w &0x7, %d0
lsr.b &0x4, %d1
and.w &0x7, %d1
mov.w %d0, NDRSAVE(%a6) # save Dr for later
mov.w %d1, NDQSAVE(%a6) # save Dq for later
# fetch %dr and %dq directly off stack since all regs are saved there
mov.l (EXC_DREGS,%a6,%d0.w*4), %d5 # get dividend hi
mov.l (EXC_DREGS,%a6,%d1.w*4), %d6 # get dividend lo
# separate signed and unsigned divide
btst &0x3, EXC_EXTWORD(%a6) # signed or unsigned?
beq.b dspecialcases # use positive divide
# save the sign of the divisor
# make divisor unsigned if it's negative
tst.l %d7 # chk sign of divisor
slt NDIVISOR(%a6) # save sign of divisor
bpl.b dsgndividend
neg.l %d7 # complement negative divisor
# save the sign of the dividend
# make dividend unsigned if it's negative
dsgndividend:
tst.l %d5 # chk sign of hi(dividend)
slt NDIVIDEND(%a6) # save sign of dividend
bpl.b dspecialcases
mov.w &0x0, %cc # clear 'X' cc bit
negx.l %d6 # complement signed dividend
negx.l %d5
# extract some special cases:
# - is (dividend == 0) ?
# - is (hi(dividend) == 0 && (divisor <= lo(dividend))) ? (32-bit div)
dspecialcases:
tst.l %d5 # is (hi(dividend) == 0)
bne.b dnormaldivide # no, so try it the long way
tst.l %d6 # is (lo(dividend) == 0), too
beq.w ddone # yes, so (dividend == 0)
cmp.l %d7,%d6 # is (divisor <= lo(dividend))
bls.b d32bitdivide # yes, so use 32 bit divide
exg %d5,%d6 # q = 0, r = dividend
bra.w divfinish # can't divide, we're done.
d32bitdivide:
tdivu.l %d7, %d5:%d6 # it's only a 32/32 bit div!
bra.b divfinish
dnormaldivide:
# last special case:
# - is hi(dividend) >= divisor ? if yes, then overflow
cmp.l %d7,%d5
bls.b ddovf # answer won't fit in 32 bits
# perform the divide algorithm:
bsr.l dclassical # do int divide
# separate into signed and unsigned finishes.
divfinish:
btst &0x3, EXC_EXTWORD(%a6) # do divs, divu separately
beq.b ddone # divu has no processing!!!
# it was a divs.l, so ccode setting is a little more complicated...
tst.b NDIVIDEND(%a6) # remainder has same sign
beq.b dcc # as dividend.
neg.l %d5 # sgn(rem) = sgn(dividend)
dcc:
mov.b NDIVISOR(%a6), %d0
eor.b %d0, NDIVIDEND(%a6) # chk if quotient is negative
beq.b dqpos # branch to quot positive
# 0x80000000 is the largest number representable as a 32-bit negative
# number. the negative of 0x80000000 is 0x80000000.
cmpi.l %d6, &0x80000000 # will (-quot) fit in 32 bits?
bhi.b ddovf
neg.l %d6 # make (-quot) 2's comp
bra.b ddone
dqpos:
btst &0x1f, %d6 # will (+quot) fit in 32 bits?
bne.b ddovf
ddone:
# at this point, result is normal so ccodes are set based on result.
mov.w EXC_CC(%a6), %cc
tst.l %d6 # set %ccode bits
mov.w %cc, EXC_CC(%a6)
mov.w NDRSAVE(%a6), %d0 # get Dr off stack
mov.w NDQSAVE(%a6), %d1 # get Dq off stack
# if the register numbers are the same, only the quotient gets saved.
# so, if we always save the quotient second, we save ourselves a cmp&beq
mov.l %d5, (EXC_DREGS,%a6,%d0.w*4) # save remainder
mov.l %d6, (EXC_DREGS,%a6,%d1.w*4) # save quotient
rts
ddovf:
bset &0x1, EXC_CC+1(%a6) # 'V' set on overflow
bclr &0x0, EXC_CC+1(%a6) # 'C' cleared on overflow
rts
div64eq0:
andi.b &0x1e, EXC_CC+1(%a6) # clear 'C' bit on divbyzero
ori.b &idbyz_flg,SPCOND_FLG(%a6) # set "special case" flag
rts
###########################################################################
#########################################################################
# This routine uses the 'classical' Algorithm D from Donald Knuth's #
# Art of Computer Programming, vol II, Seminumerical Algorithms. #
# For this implementation b=2**16, and the target is U1U2U3U4/V1V2, #
# where U,V are words of the quadword dividend and longword divisor, #
# and U1, V1 are the most significant words. #
# #
# The most sig. longword of the 64 bit dividend must be in %d5, least #
# in %d6. The divisor must be in the variable ddivisor, and the #
# signed/unsigned flag ddusign must be set (0=unsigned,1=signed). #
# The quotient is returned in %d6, remainder in %d5, unless the #
# v (overflow) bit is set in the saved %ccr. If overflow, the dividend #
# is unchanged. #
#########################################################################
dclassical:
# if the divisor msw is 0, use simpler algorithm then the full blown
# one at ddknuth:
cmpi.l %d7, &0xffff
bhi.b ddknuth # go use D. Knuth algorithm
# Since the divisor is only a word (and larger than the mslw of the dividend),
# a simpler algorithm may be used :
# In the general case, four quotient words would be created by
# dividing the divisor word into each dividend word. In this case,
# the first two quotient words must be zero, or overflow would occur.
# Since we already checked this case above, we can treat the most significant
# longword of the dividend as (0) remainder (see Knuth) and merely complete
# the last two divisions to get a quotient longword and word remainder:
clr.l %d1
swap %d5 # same as r*b if previous step rqd
swap %d6 # get u3 to lsw position
mov.w %d6, %d5 # rb + u3
divu.w %d7, %d5
mov.w %d5, %d1 # first quotient word
swap %d6 # get u4
mov.w %d6, %d5 # rb + u4
divu.w %d7, %d5
swap %d1
mov.w %d5, %d1 # 2nd quotient 'digit'
clr.w %d5
swap %d5 # now remainder
mov.l %d1, %d6 # and quotient
rts
ddknuth:
# In this algorithm, the divisor is treated as a 2 digit (word) number
# which is divided into a 3 digit (word) dividend to get one quotient
# digit (word). After subtraction, the dividend is shifted and the
# process repeated. Before beginning, the divisor and quotient are
# 'normalized' so that the process of estimating the quotient digit
# will yield verifiably correct results..
clr.l DDNORMAL(%a6) # count of shifts for normalization
clr.b DDSECOND(%a6) # clear flag for quotient digits
clr.l %d1 # %d1 will hold trial quotient
ddnchk:
btst &31, %d7 # must we normalize? first word of
bne.b ddnormalized # divisor (V1) must be >= 65536/2
addq.l &0x1, DDNORMAL(%a6) # count normalization shifts
lsl.l &0x1, %d7 # shift the divisor
lsl.l &0x1, %d6 # shift u4,u3 with overflow to u2
roxl.l &0x1, %d5 # shift u1,u2
bra.w ddnchk
ddnormalized:
# Now calculate an estimate of the quotient words (msw first, then lsw).
# The comments use subscripts for the first quotient digit determination.
mov.l %d7, %d3 # divisor
mov.l %d5, %d2 # dividend mslw
swap %d2
swap %d3
cmp.w %d2, %d3 # V1 = U1 ?
bne.b ddqcalc1
mov.w &0xffff, %d1 # use max trial quotient word
bra.b ddadj0
ddqcalc1:
mov.l %d5, %d1
divu.w %d3, %d1 # use quotient of mslw/msw
andi.l &0x0000ffff, %d1 # zero any remainder
ddadj0:
# now test the trial quotient and adjust. This step plus the
# normalization assures (according to Knuth) that the trial
# quotient will be at worst 1 too large.
mov.l %d6, -(%sp)
clr.w %d6 # word u3 left
swap %d6 # in lsw position
ddadj1: mov.l %d7, %d3
mov.l %d1, %d2
mulu.w %d7, %d2 # V2q
swap %d3
mulu.w %d1, %d3 # V1q
mov.l %d5, %d4 # U1U2
sub.l %d3, %d4 # U1U2 - V1q
swap %d4
mov.w %d4,%d0
mov.w %d6,%d4 # insert lower word (U3)
tst.w %d0 # is upper word set?
bne.w ddadjd1
# add.l %d6, %d4 # (U1U2 - V1q) + U3
cmp.l %d2, %d4
bls.b ddadjd1 # is V2q > (U1U2-V1q) + U3 ?
subq.l &0x1, %d1 # yes, decrement and recheck
bra.b ddadj1
ddadjd1:
# now test the word by multiplying it by the divisor (V1V2) and comparing
# the 3 digit (word) result with the current dividend words
mov.l %d5, -(%sp) # save %d5 (%d6 already saved)
mov.l %d1, %d6
swap %d6 # shift answer to ms 3 words
mov.l %d7, %d5
bsr.l dmm2
mov.l %d5, %d2 # now %d2,%d3 are trial*divisor
mov.l %d6, %d3
mov.l (%sp)+, %d5 # restore dividend
mov.l (%sp)+, %d6
sub.l %d3, %d6
subx.l %d2, %d5 # subtract double precision
bcc dd2nd # no carry, do next quotient digit
subq.l &0x1, %d1 # q is one too large
# need to add back divisor longword to current ms 3 digits of dividend
# - according to Knuth, this is done only 2 out of 65536 times for random
# divisor, dividend selection.
clr.l %d2
mov.l %d7, %d3
swap %d3
clr.w %d3 # %d3 now ls word of divisor
add.l %d3, %d6 # aligned with 3rd word of dividend
addx.l %d2, %d5
mov.l %d7, %d3
clr.w %d3 # %d3 now ms word of divisor
swap %d3 # aligned with 2nd word of dividend
add.l %d3, %d5
dd2nd:
tst.b DDSECOND(%a6) # both q words done?
bne.b ddremain
# first quotient digit now correct. store digit and shift the
# (subtracted) dividend
mov.w %d1, DDQUOTIENT(%a6)
clr.l %d1
swap %d5
swap %d6
mov.w %d6, %d5
clr.w %d6
st DDSECOND(%a6) # second digit
bra.w ddnormalized
ddremain:
# add 2nd word to quotient, get the remainder.
mov.w %d1, DDQUOTIENT+2(%a6)
# shift down one word/digit to renormalize remainder.
mov.w %d5, %d6
swap %d6
swap %d5
mov.l DDNORMAL(%a6), %d7 # get norm shift count
beq.b ddrn
subq.l &0x1, %d7 # set for loop count
ddnlp:
lsr.l &0x1, %d5 # shift into %d6
roxr.l &0x1, %d6
dbf %d7, ddnlp
ddrn:
mov.l %d6, %d5 # remainder
mov.l DDQUOTIENT(%a6), %d6 # quotient
rts
dmm2:
# factors for the 32X32->64 multiplication are in %d5 and %d6.
# returns 64 bit result in %d5 (hi) %d6(lo).
# destroys %d2,%d3,%d4.
# multiply hi,lo words of each factor to get 4 intermediate products
mov.l %d6, %d2
mov.l %d6, %d3
mov.l %d5, %d4
swap %d3
swap %d4
mulu.w %d5, %d6 # %d6 <- lsw*lsw
mulu.w %d3, %d5 # %d5 <- msw-dest*lsw-source
mulu.w %d4, %d2 # %d2 <- msw-source*lsw-dest
mulu.w %d4, %d3 # %d3 <- msw*msw
# now use swap and addx to consolidate to two longwords
clr.l %d4
swap %d6
add.w %d5, %d6 # add msw of l*l to lsw of m*l product
addx.w %d4, %d3 # add any carry to m*m product
add.w %d2, %d6 # add in lsw of other m*l product
addx.w %d4, %d3 # add any carry to m*m product
swap %d6 # %d6 is low 32 bits of final product
clr.w %d5
clr.w %d2 # lsw of two mixed products used,
swap %d5 # now use msws of longwords
swap %d2
add.l %d2, %d5
add.l %d3, %d5 # %d5 now ms 32 bits of final product
rts
##########
dcontrolmodel_s:
movq.l &LONG,%d0
bsr.l _calc_ea # calc <ea>
cmpi.b SPCOND_FLG(%a6),&immed_flg # immediate addressing mode?
beq.b dimmed # yes
mov.l %a0,%a2
bsr.l _dmem_read_long # fetch divisor from <ea>
tst.l %d1 # dfetch error?
bne.b div64_err # yes
mov.l %d0, %d7
bra.w dgotsrcl
# we have to split out immediate data here because it must be read using
# imem_read() instead of dmem_read(). this becomes especially important
# if the fetch runs into some deadly fault.
dimmed:
addq.l &0x4,EXC_EXTWPTR(%a6)
bsr.l _imem_read_long # read immediate value
tst.l %d1 # ifetch error?
bne.l isp_iacc # yes
mov.l %d0,%d7
bra.w dgotsrcl
##########
# if dmem_read_long() returns a fail message in d1, the package
# must create an access error frame. here, we pass a skeleton fslw
# and the failing address to the routine that creates the new frame.
# also, we call isp_restore in case the effective addressing mode was
# (an)+ or -(an) in which case the previous "an" value must be restored.
# FSLW:
# read = true
# size = longword
# TM = data
# software emulation error = true
div64_err:
bsr.l isp_restore # restore addr reg
mov.l %a2,%a0 # pass failing address
mov.l &0x01010001,%d0 # pass fslw
bra.l isp_dacc
#########################################################################
# XDEF **************************************************************** #
# _mul64(): routine to emulate mul{u,s}.l <ea>,Dh:Dl 32x32->64 #
# #
# XREF **************************************************************** #
# _calc_ea() - calculate effective address #
# isp_iacc() - handle instruction access error exception #
# isp_dacc() - handle data access error exception #
# isp_restore() - restore An on access error w/ -() or ()+ #
# #
# INPUT *************************************************************** #
# none #
# #
# OUTPUT ************************************************************** #
# If exiting through isp_dacc... #
# a0 = failing address #
# d0 = FSLW #
# else #
# none #
# #
# ALGORITHM *********************************************************** #
# First, decode the operand location. If it's in Dn, fetch from #
# the stack. If it's in memory, use _calc_ea() to calculate the #
# effective address. Use _dmem_read_long() to fetch at that address. #
# Unless the operand is immediate data. Then use _imem_read_long(). #
# Send failures to isp_dacc() or isp_iacc() as appropriate. #
# If the operands are signed, make them unsigned and save the #
# sign info for later. Perform the multiplication using 16x16->32 #
# unsigned multiplies and "add" instructions. Store the high and low #
# portions of the result in the appropriate data registers on the #
# stack. Calculate the condition codes, also. #
# #
#########################################################################
#############
# mul(u,s)l #
#############
global _mul64
_mul64:
mov.b EXC_OPWORD+1(%a6), %d0 # extract src {mode,reg}
cmpi.b %d0, &0x7 # is src mode Dn or other?
bgt.w mul64_memop # src is in memory
# multiplier operand in the data register file.
# must extract the register number and fetch the operand from the stack.
mul64_regop:
andi.w &0x7, %d0 # extract Dn
mov.l (EXC_DREGS,%a6,%d0.w*4), %d3 # fetch multiplier
# multiplier is in %d3. now, extract Dl and Dh fields and fetch the
# multiplicand from the data register specified by Dl.
mul64_multiplicand:
mov.w EXC_EXTWORD(%a6), %d2 # fetch ext word
clr.w %d1 # clear Dh reg
mov.b %d2, %d1 # grab Dh
rol.w &0x4, %d2 # align Dl byte
andi.w &0x7, %d2 # extract Dl
mov.l (EXC_DREGS,%a6,%d2.w*4), %d4 # get multiplicand
# check for the case of "zero" result early
tst.l %d4 # test multiplicand
beq.w mul64_zero # handle zero separately
tst.l %d3 # test multiplier
beq.w mul64_zero # handle zero separately
# multiplier is in %d3 and multiplicand is in %d4.
# if the operation is to be signed, then the operands are converted
# to unsigned and the result sign is saved for the end.
clr.b EXC_TEMP(%a6) # clear temp space
btst &0x3, EXC_EXTWORD(%a6) # signed or unsigned?
beq.b mul64_alg # unsigned; skip sgn calc
tst.l %d3 # is multiplier negative?
bge.b mul64_chk_md_sgn # no
neg.l %d3 # make multiplier positive
ori.b &0x1, EXC_TEMP(%a6) # save multiplier sgn
# the result sign is the exclusive or of the operand sign bits.
mul64_chk_md_sgn:
tst.l %d4 # is multiplicand negative?
bge.b mul64_alg # no
neg.l %d4 # make multiplicand positive
eori.b &0x1, EXC_TEMP(%a6) # calculate correct sign
#########################################################################
# 63 32 0 #
# ---------------------------- #
# | hi(mplier) * hi(mplicand)| #
# ---------------------------- #
# ----------------------------- #
# | hi(mplier) * lo(mplicand) | #
# ----------------------------- #
# ----------------------------- #
# | lo(mplier) * hi(mplicand) | #
# ----------------------------- #
# | ----------------------------- #
# --|-- | lo(mplier) * lo(mplicand) | #
# | ----------------------------- #
# ======================================================== #
# -------------------------------------------------------- #
# | hi(result) | lo(result) | #
# -------------------------------------------------------- #
#########################################################################
mul64_alg:
# load temp registers with operands
mov.l %d3, %d5 # mr in %d5
mov.l %d3, %d6 # mr in %d6
mov.l %d4, %d7 # md in %d7
swap %d6 # hi(mr) in lo %d6
swap %d7 # hi(md) in lo %d7
# complete necessary multiplies:
mulu.w %d4, %d3 # [1] lo(mr) * lo(md)
mulu.w %d6, %d4 # [2] hi(mr) * lo(md)
mulu.w %d7, %d5 # [3] lo(mr) * hi(md)
mulu.w %d7, %d6 # [4] hi(mr) * hi(md)
# add lo portions of [2],[3] to hi portion of [1].
# add carries produced from these adds to [4].
# lo([1]) is the final lo 16 bits of the result.
clr.l %d7 # load %d7 w/ zero value
swap %d3 # hi([1]) <==> lo([1])
add.w %d4, %d3 # hi([1]) + lo([2])
addx.l %d7, %d6 # [4] + carry
add.w %d5, %d3 # hi([1]) + lo([3])
addx.l %d7, %d6 # [4] + carry
swap %d3 # lo([1]) <==> hi([1])
# lo portions of [2],[3] have been added in to final result.
# now, clear lo, put hi in lo reg, and add to [4]
clr.w %d4 # clear lo([2])
clr.w %d5 # clear hi([3])
swap %d4 # hi([2]) in lo %d4
swap %d5 # hi([3]) in lo %d5
add.l %d5, %d4 # [4] + hi([2])
add.l %d6, %d4 # [4] + hi([3])
# unsigned result is now in {%d4,%d3}
tst.b EXC_TEMP(%a6) # should result be signed?
beq.b mul64_done # no
# result should be a signed negative number.
# compute 2's complement of the unsigned number:
# -negate all bits and add 1
mul64_neg:
not.l %d3 # negate lo(result) bits
not.l %d4 # negate hi(result) bits
addq.l &1, %d3 # add 1 to lo(result)
addx.l %d7, %d4 # add carry to hi(result)
# the result is saved to the register file.
# for '040 compatibility, if Dl == Dh then only the hi(result) is
# saved. so, saving hi after lo accomplishes this without need to
# check Dl,Dh equality.
mul64_done:
mov.l %d3, (EXC_DREGS,%a6,%d2.w*4) # save lo(result)
mov.w &0x0, %cc
mov.l %d4, (EXC_DREGS,%a6,%d1.w*4) # save hi(result)
# now, grab the condition codes. only one that can be set is 'N'.
# 'N' CAN be set if the operation is unsigned if bit 63 is set.
mov.w %cc, %d7 # fetch %ccr to see if 'N' set
andi.b &0x8, %d7 # extract 'N' bit
mul64_ccode_set:
mov.b EXC_CC+1(%a6), %d6 # fetch previous %ccr
andi.b &0x10, %d6 # all but 'X' bit changes
or.b %d7, %d6 # group 'X' and 'N'
mov.b %d6, EXC_CC+1(%a6) # save new %ccr
rts
# one or both of the operands is zero so the result is also zero.
# save the zero result to the register file and set the 'Z' ccode bit.
mul64_zero:
clr.l (EXC_DREGS,%a6,%d2.w*4) # save lo(result)
clr.l (EXC_DREGS,%a6,%d1.w*4) # save hi(result)
movq.l &0x4, %d7 # set 'Z' ccode bit
bra.b mul64_ccode_set # finish ccode set
##########
# multiplier operand is in memory at the effective address.
# must calculate the <ea> and go fetch the 32-bit operand.
mul64_memop:
movq.l &LONG, %d0 # pass # of bytes
bsr.l _calc_ea # calculate <ea>
cmpi.b SPCOND_FLG(%a6),&immed_flg # immediate addressing mode?
beq.b mul64_immed # yes
mov.l %a0,%a2
bsr.l _dmem_read_long # fetch src from addr (%a0)
tst.l %d1 # dfetch error?
bne.w mul64_err # yes
mov.l %d0, %d3 # store multiplier in %d3
bra.w mul64_multiplicand
# we have to split out immediate data here because it must be read using
# imem_read() instead of dmem_read(). this becomes especially important
# if the fetch runs into some deadly fault.
mul64_immed:
addq.l &0x4,EXC_EXTWPTR(%a6)
bsr.l _imem_read_long # read immediate value
tst.l %d1 # ifetch error?
bne.l isp_iacc # yes
mov.l %d0,%d3
bra.w mul64_multiplicand
##########
# if dmem_read_long() returns a fail message in d1, the package
# must create an access error frame. here, we pass a skeleton fslw
# and the failing address to the routine that creates the new frame.
# also, we call isp_restore in case the effective addressing mode was
# (an)+ or -(an) in which case the previous "an" value must be restored.
# FSLW:
# read = true
# size = longword
# TM = data
# software emulation error = true
mul64_err:
bsr.l isp_restore # restore addr reg
mov.l %a2,%a0 # pass failing address
mov.l &0x01010001,%d0 # pass fslw
bra.l isp_dacc
#########################################################################
# XDEF **************************************************************** #
# _compandset2(): routine to emulate cas2() #
# (internal to package) #
# #
# _isp_cas2_finish(): store ccodes, store compare regs #
# (external to package) #
# #
# XREF **************************************************************** #
# _real_lock_page() - "callout" to lock op's page from page-outs #
# _cas_terminate2() - access error exit #
# _real_cas2() - "callout" to core cas2 emulation code #
# _real_unlock_page() - "callout" to unlock page #
# #
# INPUT *************************************************************** #
# _compandset2(): #
# d0 = instruction extension word #
# #
# _isp_cas2_finish(): #
# see cas2 core emulation code #
# #
# OUTPUT ************************************************************** #
# _compandset2(): #
# see cas2 core emulation code #
# #
# _isp_cas_finish(): #
# None (register file or memroy changed as appropriate) #
# #
# ALGORITHM *********************************************************** #
# compandset2(): #
# Decode the instruction and fetch the appropriate Update and #
# Compare operands. Then call the "callout" _real_lock_page() for each #
# memory operand address so that the operating system can keep these #
# pages from being paged out. If either _real_lock_page() fails, exit #
# through _cas_terminate2(). Don't forget to unlock the 1st locked page #
# using _real_unlock_paged() if the 2nd lock-page fails. #
# Finally, branch to the core cas2 emulation code by calling the #
# "callout" _real_cas2(). #
# #
# _isp_cas2_finish(): #
# Re-perform the comparison so we can determine the condition #
# codes which were too much trouble to keep around during the locked #
# emulation. Then unlock each operands page by calling the "callout" #
# _real_unlock_page(). #
# #
#########################################################################
set ADDR1, EXC_TEMP+0xc
set ADDR2, EXC_TEMP+0x0
set DC2, EXC_TEMP+0xa
set DC1, EXC_TEMP+0x8
global _compandset2
_compandset2:
mov.l %d0,EXC_TEMP+0x4(%a6) # store for possible restart
mov.l %d0,%d1 # extension word in d0
rol.w &0x4,%d0
andi.w &0xf,%d0 # extract Rn2
mov.l (EXC_DREGS,%a6,%d0.w*4),%a1 # fetch ADDR2
mov.l %a1,ADDR2(%a6)
mov.l %d1,%d0
lsr.w &0x6,%d1
andi.w &0x7,%d1 # extract Du2
mov.l (EXC_DREGS,%a6,%d1.w*4),%d5 # fetch Update2 Op
andi.w &0x7,%d0 # extract Dc2
mov.l (EXC_DREGS,%a6,%d0.w*4),%d3 # fetch Compare2 Op
mov.w %d0,DC2(%a6)
mov.w EXC_EXTWORD(%a6),%d0
mov.l %d0,%d1
rol.w &0x4,%d0
andi.w &0xf,%d0 # extract Rn1
mov.l (EXC_DREGS,%a6,%d0.w*4),%a0 # fetch ADDR1
mov.l %a0,ADDR1(%a6)
mov.l %d1,%d0
lsr.w &0x6,%d1
andi.w &0x7,%d1 # extract Du1
mov.l (EXC_DREGS,%a6,%d1.w*4),%d4 # fetch Update1 Op
andi.w &0x7,%d0 # extract Dc1
mov.l (EXC_DREGS,%a6,%d0.w*4),%d2 # fetch Compare1 Op
mov.w %d0,DC1(%a6)
btst &0x1,EXC_OPWORD(%a6) # word or long?
sne %d7
btst &0x5,EXC_ISR(%a6) # user or supervisor?
sne %d6
mov.l %a0,%a2
mov.l %a1,%a3
mov.l %d7,%d1 # pass size
mov.l %d6,%d0 # pass mode
bsr.l _real_lock_page # lock page
mov.l %a2,%a0
tst.l %d0 # error?
bne.l _cas_terminate2 # yes
mov.l %d7,%d1 # pass size
mov.l %d6,%d0 # pass mode
mov.l %a3,%a0 # pass addr
bsr.l _real_lock_page # lock page
mov.l %a3,%a0
tst.l %d0 # error?
bne.b cas_preterm # yes
mov.l %a2,%a0
mov.l %a3,%a1
bra.l _real_cas2
# if the 2nd lock attempt fails, then we must still unlock the
# first page(s).
cas_preterm:
mov.l %d0,-(%sp) # save FSLW
mov.l %d7,%d1 # pass size
mov.l %d6,%d0 # pass mode
mov.l %a2,%a0 # pass ADDR1
bsr.l _real_unlock_page # unlock first page(s)
mov.l (%sp)+,%d0 # restore FSLW
mov.l %a3,%a0 # pass failing addr
bra.l _cas_terminate2
#############################################################
global _isp_cas2_finish
_isp_cas2_finish:
btst &0x1,EXC_OPWORD(%a6)
bne.b cas2_finish_l
mov.w EXC_CC(%a6),%cc # load old ccodes
cmp.w %d0,%d2
bne.b cas2_finish_w_save
cmp.w %d1,%d3
cas2_finish_w_save:
mov.w %cc,EXC_CC(%a6) # save new ccodes
tst.b %d4 # update compare reg?
bne.b cas2_finish_w_done # no
mov.w DC2(%a6),%d3 # fetch Dc2
mov.w %d1,(2+EXC_DREGS,%a6,%d3.w*4) # store new Compare2 Op
mov.w DC1(%a6),%d2 # fetch Dc1
mov.w %d0,(2+EXC_DREGS,%a6,%d2.w*4) # store new Compare1 Op
cas2_finish_w_done:
btst &0x5,EXC_ISR(%a6)
sne %d2
mov.l %d2,%d0 # pass mode
sf %d1 # pass size
mov.l ADDR1(%a6),%a0 # pass ADDR1
bsr.l _real_unlock_page # unlock page
mov.l %d2,%d0 # pass mode
sf %d1 # pass size
mov.l ADDR2(%a6),%a0 # pass ADDR2
bsr.l _real_unlock_page # unlock page
rts
cas2_finish_l:
mov.w EXC_CC(%a6),%cc # load old ccodes
cmp.l %d0,%d2
bne.b cas2_finish_l_save
cmp.l %d1,%d3
cas2_finish_l_save:
mov.w %cc,EXC_CC(%a6) # save new ccodes
tst.b %d4 # update compare reg?
bne.b cas2_finish_l_done # no
mov.w DC2(%a6),%d3 # fetch Dc2
mov.l %d1,(EXC_DREGS,%a6,%d3.w*4) # store new Compare2 Op
mov.w DC1(%a6),%d2 # fetch Dc1
mov.l %d0,(EXC_DREGS,%a6,%d2.w*4) # store new Compare1 Op
cas2_finish_l_done:
btst &0x5,EXC_ISR(%a6)
sne %d2
mov.l %d2,%d0 # pass mode
st %d1 # pass size
mov.l ADDR1(%a6),%a0 # pass ADDR1
bsr.l _real_unlock_page # unlock page
mov.l %d2,%d0 # pass mode
st %d1 # pass size
mov.l ADDR2(%a6),%a0 # pass ADDR2
bsr.l _real_unlock_page # unlock page
rts
########
global cr_cas2
cr_cas2:
mov.l EXC_TEMP+0x4(%a6),%d0
bra.w _compandset2
#########################################################################
# XDEF **************************************************************** #
# _compandset(): routine to emulate cas w/ misaligned <ea> #
# (internal to package) #
# _isp_cas_finish(): routine called when cas emulation completes #
# (external and internal to package) #
# _isp_cas_restart(): restart cas emulation after a fault #
# (external to package) #
# _isp_cas_terminate(): create access error stack frame on fault #
# (external and internal to package) #
# _isp_cas_inrange(): checks whether instr addess is within range #
# of core cas/cas2emulation code #
# (external to package) #
# #
# XREF **************************************************************** #
# _calc_ea(): calculate effective address #
# #
# INPUT *************************************************************** #
# compandset(): #
# none #
# _isp_cas_restart(): #
# d6 = previous sfc/dfc #
# _isp_cas_finish(): #
# _isp_cas_terminate(): #
# a0 = failing address #
# d0 = FSLW #
# d6 = previous sfc/dfc #
# _isp_cas_inrange(): #
# a0 = instruction address to be checked #
# #
# OUTPUT ************************************************************** #
# compandset(): #
# none #
# _isp_cas_restart(): #
# a0 = effective address #
# d7 = word or longword flag #
# _isp_cas_finish(): #
# a0 = effective address #
# _isp_cas_terminate(): #
# initial register set before emulation exception #
# _isp_cas_inrange(): #
# d0 = 0 => in range; -1 => out of range #
# #
# ALGORITHM *********************************************************** #
# #
# compandset(): #
# First, calculate the effective address. Then, decode the #
# instruction word and fetch the "compare" (DC) and "update" (Du) #
# operands. #
# Next, call the external routine _real_lock_page() so that the #
# operating system can keep this page from being paged out while we're #
# in this routine. If this call fails, jump to _cas_terminate2(). #
# The routine then branches to _real_cas(). This external routine #
# that actually emulates cas can be supplied by the external os or #
# made to point directly back into the 060ISP which has a routine for #
# this purpose. #
# #
# _isp_cas_finish(): #
# Either way, after emulation, the package is re-entered at #
# _isp_cas_finish(). This routine re-compares the operands in order to #
# set the condition codes. Finally, these routines will call #
# _real_unlock_page() in order to unlock the pages that were previously #
# locked. #
# #
# _isp_cas_restart(): #
# This routine can be entered from an access error handler where #
# the emulation sequence should be re-started from the beginning. #
# #
# _isp_cas_terminate(): #
# This routine can be entered from an access error handler where #
# an emulation operand access failed and the operating system would #
# like an access error stack frame created instead of the current #
# unimplemented integer instruction frame. #
# Also, the package enters here if a call to _real_lock_page() #
# fails. #
# #
# _isp_cas_inrange(): #
# Checks to see whether the instruction address passed to it in #
# a0 is within the software package cas/cas2 emulation routines. This #
# can be helpful for an operating system to determine whether an access #
# error during emulation was due to a cas/cas2 emulation access. #
# #
#########################################################################
set DC, EXC_TEMP+0x8
set ADDR, EXC_TEMP+0x4
global _compandset
_compandset:
btst &0x1,EXC_OPWORD(%a6) # word or long operation?
bne.b compandsetl # long
compandsetw:
movq.l &0x2,%d0 # size = 2 bytes
bsr.l _calc_ea # a0 = calculated <ea>
mov.l %a0,ADDR(%a6) # save <ea> for possible restart
sf %d7 # clear d7 for word size
bra.b compandsetfetch
compandsetl:
movq.l &0x4,%d0 # size = 4 bytes
bsr.l _calc_ea # a0 = calculated <ea>
mov.l %a0,ADDR(%a6) # save <ea> for possible restart
st %d7 # set d7 for longword size
compandsetfetch:
mov.w EXC_EXTWORD(%a6),%d0 # fetch cas extension word
mov.l %d0,%d1 # make a copy
lsr.w &0x6,%d0
andi.w &0x7,%d0 # extract Du
mov.l (EXC_DREGS,%a6,%d0.w*4),%d2 # get update operand
andi.w &0x7,%d1 # extract Dc
mov.l (EXC_DREGS,%a6,%d1.w*4),%d4 # get compare operand
mov.w %d1,DC(%a6) # save Dc
btst &0x5,EXC_ISR(%a6) # which mode for exception?
sne %d6 # set on supervisor mode
mov.l %a0,%a2 # save temporarily
mov.l %d7,%d1 # pass size
mov.l %d6,%d0 # pass mode
bsr.l _real_lock_page # lock page
tst.l %d0 # did error occur?
bne.w _cas_terminate2 # yes, clean up the mess
mov.l %a2,%a0 # pass addr in a0
bra.l _real_cas
########
global _isp_cas_finish
_isp_cas_finish:
btst &0x1,EXC_OPWORD(%a6)
bne.b cas_finish_l
# just do the compare again since it's faster than saving the ccodes
# from the locked routine...
cas_finish_w:
mov.w EXC_CC(%a6),%cc # restore cc
cmp.w %d0,%d4 # do word compare
mov.w %cc,EXC_CC(%a6) # save cc
tst.b %d1 # update compare reg?
bne.b cas_finish_w_done # no
mov.w DC(%a6),%d3
mov.w %d0,(EXC_DREGS+2,%a6,%d3.w*4) # Dc = destination
cas_finish_w_done:
mov.l ADDR(%a6),%a0 # pass addr
sf %d1 # pass size
btst &0x5,EXC_ISR(%a6)
sne %d0 # pass mode
bsr.l _real_unlock_page # unlock page
rts
# just do the compare again since it's faster than saving the ccodes
# from the locked routine...
cas_finish_l:
mov.w EXC_CC(%a6),%cc # restore cc
cmp.l %d0,%d4 # do longword compare
mov.w %cc,EXC_CC(%a6) # save cc
tst.b %d1 # update compare reg?
bne.b cas_finish_l_done # no
mov.w DC(%a6),%d3
mov.l %d0,(EXC_DREGS,%a6,%d3.w*4) # Dc = destination
cas_finish_l_done:
mov.l ADDR(%a6),%a0 # pass addr
st %d1 # pass size
btst &0x5,EXC_ISR(%a6)
sne %d0 # pass mode
bsr.l _real_unlock_page # unlock page
rts
########
global _isp_cas_restart
_isp_cas_restart:
mov.l %d6,%sfc # restore previous sfc
mov.l %d6,%dfc # restore previous dfc
cmpi.b EXC_OPWORD+1(%a6),&0xfc # cas or cas2?
beq.l cr_cas2 # cas2
cr_cas:
mov.l ADDR(%a6),%a0 # load <ea>
btst &0x1,EXC_OPWORD(%a6) # word or long operation?
sne %d7 # set d7 accordingly
bra.w compandsetfetch
########
# At this stage, it would be nice if d0 held the FSLW.
global _isp_cas_terminate
_isp_cas_terminate:
mov.l %d6,%sfc # restore previous sfc
mov.l %d6,%dfc # restore previous dfc
global _cas_terminate2
_cas_terminate2:
mov.l %a0,%a2 # copy failing addr to a2
mov.l %d0,-(%sp)
bsr.l isp_restore # restore An (if ()+ or -())
mov.l (%sp)+,%d0
addq.l &0x4,%sp # remove sub return addr
subq.l &0x8,%sp # make room for bigger stack
subq.l &0x8,%a6 # shift frame ptr down, too
mov.l &26,%d1 # want to move 51 longwords
lea 0x8(%sp),%a0 # get address of old stack
lea 0x0(%sp),%a1 # get address of new stack
cas_term_cont:
mov.l (%a0)+,(%a1)+ # move a longword
dbra.w %d1,cas_term_cont # keep going
mov.w &0x4008,EXC_IVOFF(%a6) # put new stk fmt, voff
mov.l %a2,EXC_IVOFF+0x2(%a6) # put faulting addr on stack
mov.l %d0,EXC_IVOFF+0x6(%a6) # put FSLW on stack
movm.l EXC_DREGS(%a6),&0x3fff # restore user regs
unlk %a6 # unlink stack frame
bra.l _real_access
########
global _isp_cas_inrange
_isp_cas_inrange:
clr.l %d0 # clear return result
lea _CASHI(%pc),%a1 # load end of CAS core code
cmp.l %a1,%a0 # is PC in range?
blt.b cin_no # no
lea _CASLO(%pc),%a1 # load begin of CAS core code
cmp.l %a0,%a1 # is PC in range?
blt.b cin_no # no
rts # yes; return d0 = 0
cin_no:
mov.l &-0x1,%d0 # out of range; return d0 = -1
rts
#################################################################
#################################################################
#################################################################
# This is the start of the cas and cas2 "core" emulation code. #
# This is the section that may need to be replaced by the host #
# OS if it is too operating system-specific. #
# Please refer to the package documentation to see how to #
# "replace" this section, if necessary. #
#################################################################
#################################################################
#################################################################
# ###### ## ###### ####
# # # # # # #
# # ###### ###### #
# # # # # #
# ###### # # ###### ######
#########################################################################
# XDEF **************************************************************** #
# _isp_cas2(): "core" emulation code for the cas2 instruction #
# #
# XREF **************************************************************** #
# _isp_cas2_finish() - only exit point for this emulation code; #
# do clean-up; calculate ccodes; store #
# Compare Ops if appropriate. #
# #
# INPUT *************************************************************** #
# *see chart below* #
# #
# OUTPUT ************************************************************** #
# *see chart below* #
# #
# ALGORITHM *********************************************************** #
# (1) Make several copies of the effective address. #
# (2) Save current SR; Then mask off all maskable interrupts. #
# (3) Save current SFC/DFC (ASSUMED TO BE EQUAL!!!); Then set #
# according to whether exception occurred in user or #
# supervisor mode. #
# (4) Use "plpaw" instruction to pre-load ATC with effective #
# address pages(s). THIS SHOULD NOT FAULT!!! The relevant #
# page(s) should have already been made resident prior to #
# entering this routine. #
# (5) Push the operand lines from the cache w/ "cpushl". #
# In the 68040, this was done within the locked region. In #
# the 68060, it is done outside of the locked region. #
# (6) Use "plpar" instruction to do a re-load of ATC entries for #
# ADDR1 since ADDR2 entries may have pushed ADDR1 out of the #
# ATC. #
# (7) Pre-fetch the core emulation instructions by executing #
# one branch within each physical line (16 bytes) of the code #
# before actually executing the code. #
# (8) Load the BUSCR w/ the bus lock value. #
# (9) Fetch the source operands using "moves". #
# (10)Do the compares. If both equal, go to step (13). #
# (11)Unequal. No update occurs. But, we do write the DST1 op #
# back to itself (as w/ the '040) so we can gracefully unlock #
# the bus (and assert LOCKE*) using BUSCR and the final move. #
# (12)Exit. #
# (13)Write update operand to the DST locations. Use BUSCR to #
# assert LOCKE* for the final write operation. #
# (14)Exit. #
# #
# The algorithm is actually implemented slightly differently #
# depending on the size of the operation and the misalignment of the #
# operands. A misaligned operand must be written in aligned chunks or #
# else the BUSCR register control gets confused. #
# #
#########################################################################
#################################################################
# THIS IS THE STATE OF THE INTEGER REGISTER FILE UPON #
# ENTERING _isp_cas2(). #
# #
# D0 = xxxxxxxx #
# D1 = xxxxxxxx #
# D2 = cmp operand 1 #
# D3 = cmp operand 2 #
# D4 = update oper 1 #
# D5 = update oper 2 #
# D6 = 'xxxxxxff if supervisor mode; 'xxxxxx00 if user mode #
# D7 = 'xxxxxxff if longword operation; 'xxxxxx00 if word #
# A0 = ADDR1 #
# A1 = ADDR2 #
# A2 = xxxxxxxx #
# A3 = xxxxxxxx #
# A4 = xxxxxxxx #
# A5 = xxxxxxxx #
# A6 = frame pointer #
# A7 = stack pointer #
#################################################################
# align 0x1000
# beginning label used by _isp_cas_inrange()
global _CASLO
_CASLO:
global _isp_cas2
_isp_cas2:
tst.b %d6 # user or supervisor mode?
bne.b cas2_supervisor # supervisor
cas2_user:
movq.l &0x1,%d0 # load user data fc
bra.b cas2_cont
cas2_supervisor:
movq.l &0x5,%d0 # load supervisor data fc
cas2_cont:
tst.b %d7 # word or longword?
beq.w cas2w # word
####
cas2l:
mov.l %a0,%a2 # copy ADDR1
mov.l %a1,%a3 # copy ADDR2
mov.l %a0,%a4 # copy ADDR1
mov.l %a1,%a5 # copy ADDR2
addq.l &0x3,%a4 # ADDR1+3
addq.l &0x3,%a5 # ADDR2+3
mov.l %a2,%d1 # ADDR1
# mask interrupts levels 0-6. save old mask value.
mov.w %sr,%d7 # save current SR
ori.w &0x0700,%sr # inhibit interrupts
# load the SFC and DFC with the appropriate mode.
movc %sfc,%d6 # save old SFC/DFC
movc %d0,%sfc # store new SFC
movc %d0,%dfc # store new DFC
# pre-load the operand ATC. no page faults should occur here because
# _real_lock_page() should have taken care of this.
plpaw (%a2) # load atc for ADDR1
plpaw (%a4) # load atc for ADDR1+3
plpaw (%a3) # load atc for ADDR2
plpaw (%a5) # load atc for ADDR2+3
# push the operand lines from the cache if they exist.
cpushl %dc,(%a2) # push line for ADDR1
cpushl %dc,(%a4) # push line for ADDR1+3
cpushl %dc,(%a3) # push line for ADDR2
cpushl %dc,(%a5) # push line for ADDR2+2
mov.l %d1,%a2 # ADDR1
addq.l &0x3,%d1
mov.l %d1,%a4 # ADDR1+3
# if ADDR1 was ATC resident before the above "plpaw" and was executed
# and it was the next entry scheduled for replacement and ADDR2
# shares the same set, then the "plpaw" for ADDR2 can push the ADDR1
# entries from the ATC. so, we do a second set of "plpa"s.
plpar (%a2) # load atc for ADDR1
plpar (%a4) # load atc for ADDR1+3
# load the BUSCR values.
mov.l &0x80000000,%a2 # assert LOCK* buscr value
mov.l &0xa0000000,%a3 # assert LOCKE* buscr value
mov.l &0x00000000,%a4 # buscr unlock value
# there are three possible mis-aligned cases for longword cas. they
# are separated because the final write which asserts LOCKE* must
# be aligned.
mov.l %a0,%d0 # is ADDR1 misaligned?
andi.b &0x3,%d0
beq.b CAS2L_ENTER # no
cmpi.b %d0,&0x2
beq.w CAS2L2_ENTER # yes; word misaligned
bra.w CAS2L3_ENTER # yes; byte misaligned
#
# D0 = dst operand 1 <-
# D1 = dst operand 2 <-
# D2 = cmp operand 1
# D3 = cmp operand 2
# D4 = update oper 1
# D5 = update oper 2
# D6 = old SFC/DFC
# D7 = old SR
# A0 = ADDR1
# A1 = ADDR2
# A2 = bus LOCK* value
# A3 = bus LOCKE* value
# A4 = bus unlock value
# A5 = xxxxxxxx
#
align 0x10
CAS2L_START:
movc %a2,%buscr # assert LOCK*
movs.l (%a1),%d1 # fetch Dest2[31:0]
movs.l (%a0),%d0 # fetch Dest1[31:0]
bra.b CAS2L_CONT
CAS2L_ENTER:
bra.b ~+16
CAS2L_CONT:
cmp.l %d0,%d2 # Dest1 - Compare1
bne.b CAS2L_NOUPDATE
cmp.l %d1,%d3 # Dest2 - Compare2
bne.b CAS2L_NOUPDATE
movs.l %d5,(%a1) # Update2[31:0] -> DEST2
bra.b CAS2L_UPDATE
bra.b ~+16
CAS2L_UPDATE:
movc %a3,%buscr # assert LOCKE*
movs.l %d4,(%a0) # Update1[31:0] -> DEST1
movc %a4,%buscr # unlock the bus
bra.b cas2l_update_done
bra.b ~+16
CAS2L_NOUPDATE:
movc %a3,%buscr # assert LOCKE*
movs.l %d0,(%a0) # Dest1[31:0] -> DEST1
movc %a4,%buscr # unlock the bus
bra.b cas2l_noupdate_done
bra.b ~+16
CAS2L_FILLER:
nop
nop
nop
nop
nop
nop
nop
bra.b CAS2L_START
####
#################################################################
# THIS MUST BE THE STATE OF THE INTEGER REGISTER FILE UPON #
# ENTERING _isp_cas2(). #
# #
# D0 = destination[31:0] operand 1 #
# D1 = destination[31:0] operand 2 #
# D2 = cmp[31:0] operand 1 #
# D3 = cmp[31:0] operand 2 #
# D4 = 'xxxxxx11 -> no reg update; 'xxxxxx00 -> update required #
# D5 = xxxxxxxx #
# D6 = xxxxxxxx #
# D7 = xxxxxxxx #
# A0 = xxxxxxxx #
# A1 = xxxxxxxx #
# A2 = xxxxxxxx #
# A3 = xxxxxxxx #
# A4 = xxxxxxxx #
# A5 = xxxxxxxx #
# A6 = frame pointer #
# A7 = stack pointer #
#################################################################
cas2l_noupdate_done:
# restore previous SFC/DFC value.
movc %d6,%sfc # restore old SFC
movc %d6,%dfc # restore old DFC
# restore previous interrupt mask level.
mov.w %d7,%sr # restore old SR
sf %d4 # indicate no update was done
bra.l _isp_cas2_finish
cas2l_update_done:
# restore previous SFC/DFC value.
movc %d6,%sfc # restore old SFC
movc %d6,%dfc # restore old DFC
# restore previous interrupt mask level.
mov.w %d7,%sr # restore old SR
st %d4 # indicate update was done
bra.l _isp_cas2_finish
####
align 0x10
CAS2L2_START:
movc %a2,%buscr # assert LOCK*
movs.l (%a1),%d1 # fetch Dest2[31:0]
movs.l (%a0),%d0 # fetch Dest1[31:0]
bra.b CAS2L2_CONT
CAS2L2_ENTER:
bra.b ~+16
CAS2L2_CONT:
cmp.l %d0,%d2 # Dest1 - Compare1
bne.b CAS2L2_NOUPDATE
cmp.l %d1,%d3 # Dest2 - Compare2
bne.b CAS2L2_NOUPDATE
movs.l %d5,(%a1) # Update2[31:0] -> Dest2
bra.b CAS2L2_UPDATE
bra.b ~+16
CAS2L2_UPDATE:
swap %d4 # get Update1[31:16]
movs.w %d4,(%a0)+ # Update1[31:16] -> DEST1
movc %a3,%buscr # assert LOCKE*
swap %d4 # get Update1[15:0]
bra.b CAS2L2_UPDATE2
bra.b ~+16
CAS2L2_UPDATE2:
movs.w %d4,(%a0) # Update1[15:0] -> DEST1+0x2
movc %a4,%buscr # unlock the bus
bra.w cas2l_update_done
nop
bra.b ~+16
CAS2L2_NOUPDATE:
swap %d0 # get Dest1[31:16]
movs.w %d0,(%a0)+ # Dest1[31:16] -> DEST1
movc %a3,%buscr # assert LOCKE*
swap %d0 # get Dest1[15:0]
bra.b CAS2L2_NOUPDATE2
bra.b ~+16
CAS2L2_NOUPDATE2:
movs.w %d0,(%a0) # Dest1[15:0] -> DEST1+0x2
movc %a4,%buscr # unlock the bus
bra.w cas2l_noupdate_done
nop
bra.b ~+16
CAS2L2_FILLER:
nop
nop
nop
nop
nop
nop
nop
bra.b CAS2L2_START
#################################
align 0x10
CAS2L3_START:
movc %a2,%buscr # assert LOCK*
movs.l (%a1),%d1 # fetch Dest2[31:0]
movs.l (%a0),%d0 # fetch Dest1[31:0]
bra.b CAS2L3_CONT
CAS2L3_ENTER:
bra.b ~+16
CAS2L3_CONT:
cmp.l %d0,%d2 # Dest1 - Compare1
bne.b CAS2L3_NOUPDATE
cmp.l %d1,%d3 # Dest2 - Compare2
bne.b CAS2L3_NOUPDATE
movs.l %d5,(%a1) # Update2[31:0] -> DEST2
bra.b CAS2L3_UPDATE
bra.b ~+16
CAS2L3_UPDATE:
rol.l &0x8,%d4 # get Update1[31:24]
movs.b %d4,(%a0)+ # Update1[31:24] -> DEST1
swap %d4 # get Update1[23:8]
movs.w %d4,(%a0)+ # Update1[23:8] -> DEST1+0x1
bra.b CAS2L3_UPDATE2
bra.b ~+16
CAS2L3_UPDATE2:
rol.l &0x8,%d4 # get Update1[7:0]
movc %a3,%buscr # assert LOCKE*
movs.b %d4,(%a0) # Update1[7:0] -> DEST1+0x3
bra.b CAS2L3_UPDATE3
nop
bra.b ~+16
CAS2L3_UPDATE3:
movc %a4,%buscr # unlock the bus
bra.w cas2l_update_done
nop
nop
nop
bra.b ~+16
CAS2L3_NOUPDATE:
rol.l &0x8,%d0 # get Dest1[31:24]
movs.b %d0,(%a0)+ # Dest1[31:24] -> DEST1
swap %d0 # get Dest1[23:8]
movs.w %d0,(%a0)+ # Dest1[23:8] -> DEST1+0x1
bra.b CAS2L3_NOUPDATE2
bra.b ~+16
CAS2L3_NOUPDATE2:
rol.l &0x8,%d0 # get Dest1[7:0]
movc %a3,%buscr # assert LOCKE*
movs.b %d0,(%a0) # Update1[7:0] -> DEST1+0x3
bra.b CAS2L3_NOUPDATE3
nop
bra.b ~+16
CAS2L3_NOUPDATE3:
movc %a4,%buscr # unlock the bus
bra.w cas2l_noupdate_done
nop
nop
nop
bra.b ~+14
CAS2L3_FILLER:
nop
nop
nop
nop
nop
nop
bra.w CAS2L3_START
#############################################################
#############################################################
cas2w:
mov.l %a0,%a2 # copy ADDR1
mov.l %a1,%a3 # copy ADDR2
mov.l %a0,%a4 # copy ADDR1
mov.l %a1,%a5 # copy ADDR2
addq.l &0x1,%a4 # ADDR1+1
addq.l &0x1,%a5 # ADDR2+1
mov.l %a2,%d1 # ADDR1
# mask interrupt levels 0-6. save old mask value.
mov.w %sr,%d7 # save current SR
ori.w &0x0700,%sr # inhibit interrupts
# load the SFC and DFC with the appropriate mode.
movc %sfc,%d6 # save old SFC/DFC
movc %d0,%sfc # store new SFC
movc %d0,%dfc # store new DFC
# pre-load the operand ATC. no page faults should occur because
# _real_lock_page() should have taken care of this.
plpaw (%a2) # load atc for ADDR1
plpaw (%a4) # load atc for ADDR1+1
plpaw (%a3) # load atc for ADDR2
plpaw (%a5) # load atc for ADDR2+1
# push the operand cache lines from the cache if they exist.
cpushl %dc,(%a2) # push line for ADDR1
cpushl %dc,(%a4) # push line for ADDR1+1
cpushl %dc,(%a3) # push line for ADDR2
cpushl %dc,(%a5) # push line for ADDR2+1
mov.l %d1,%a2 # ADDR1
addq.l &0x3,%d1
mov.l %d1,%a4 # ADDR1+3
# if ADDR1 was ATC resident before the above "plpaw" and was executed
# and it was the next entry scheduled for replacement and ADDR2
# shares the same set, then the "plpaw" for ADDR2 can push the ADDR1
# entries from the ATC. so, we do a second set of "plpa"s.
plpar (%a2) # load atc for ADDR1
plpar (%a4) # load atc for ADDR1+3
# load the BUSCR values.
mov.l &0x80000000,%a2 # assert LOCK* buscr value
mov.l &0xa0000000,%a3 # assert LOCKE* buscr value
mov.l &0x00000000,%a4 # buscr unlock value
# there are two possible mis-aligned cases for word cas. they
# are separated because the final write which asserts LOCKE* must
# be aligned.
mov.l %a0,%d0 # is ADDR1 misaligned?
btst &0x0,%d0
bne.w CAS2W2_ENTER # yes
bra.b CAS2W_ENTER # no
#
# D0 = dst operand 1 <-
# D1 = dst operand 2 <-
# D2 = cmp operand 1
# D3 = cmp operand 2
# D4 = update oper 1
# D5 = update oper 2
# D6 = old SFC/DFC
# D7 = old SR
# A0 = ADDR1
# A1 = ADDR2
# A2 = bus LOCK* value
# A3 = bus LOCKE* value
# A4 = bus unlock value
# A5 = xxxxxxxx
#
align 0x10
CAS2W_START:
movc %a2,%buscr # assert LOCK*
movs.w (%a1),%d1 # fetch Dest2[15:0]
movs.w (%a0),%d0 # fetch Dest1[15:0]
bra.b CAS2W_CONT2
CAS2W_ENTER:
bra.b ~+16
CAS2W_CONT2:
cmp.w %d0,%d2 # Dest1 - Compare1
bne.b CAS2W_NOUPDATE
cmp.w %d1,%d3 # Dest2 - Compare2
bne.b CAS2W_NOUPDATE
movs.w %d5,(%a1) # Update2[15:0] -> DEST2
bra.b CAS2W_UPDATE
bra.b ~+16
CAS2W_UPDATE:
movc %a3,%buscr # assert LOCKE*
movs.w %d4,(%a0) # Update1[15:0] -> DEST1
movc %a4,%buscr # unlock the bus
bra.b cas2w_update_done
bra.b ~+16
CAS2W_NOUPDATE:
movc %a3,%buscr # assert LOCKE*
movs.w %d0,(%a0) # Dest1[15:0] -> DEST1
movc %a4,%buscr # unlock the bus
bra.b cas2w_noupdate_done
bra.b ~+16
CAS2W_FILLER:
nop
nop
nop
nop
nop
nop
nop
bra.b CAS2W_START
####
#################################################################
# THIS MUST BE THE STATE OF THE INTEGER REGISTER FILE UPON #
# ENTERING _isp_cas2(). #
# #
# D0 = destination[15:0] operand 1 #
# D1 = destination[15:0] operand 2 #
# D2 = cmp[15:0] operand 1 #
# D3 = cmp[15:0] operand 2 #
# D4 = 'xxxxxx11 -> no reg update; 'xxxxxx00 -> update required #
# D5 = xxxxxxxx #
# D6 = xxxxxxxx #
# D7 = xxxxxxxx #
# A0 = xxxxxxxx #
# A1 = xxxxxxxx #
# A2 = xxxxxxxx #
# A3 = xxxxxxxx #
# A4 = xxxxxxxx #
# A5 = xxxxxxxx #
# A6 = frame pointer #
# A7 = stack pointer #
#################################################################
cas2w_noupdate_done:
# restore previous SFC/DFC value.
movc %d6,%sfc # restore old SFC
movc %d6,%dfc # restore old DFC
# restore previous interrupt mask level.
mov.w %d7,%sr # restore old SR
sf %d4 # indicate no update was done
bra.l _isp_cas2_finish
cas2w_update_done:
# restore previous SFC/DFC value.
movc %d6,%sfc # restore old SFC
movc %d6,%dfc # restore old DFC
# restore previous interrupt mask level.
mov.w %d7,%sr # restore old SR
st %d4 # indicate update was done
bra.l _isp_cas2_finish
####
align 0x10
CAS2W2_START:
movc %a2,%buscr # assert LOCK*
movs.w (%a1),%d1 # fetch Dest2[15:0]
movs.w (%a0),%d0 # fetch Dest1[15:0]
bra.b CAS2W2_CONT2
CAS2W2_ENTER:
bra.b ~+16
CAS2W2_CONT2:
cmp.w %d0,%d2 # Dest1 - Compare1
bne.b CAS2W2_NOUPDATE
cmp.w %d1,%d3 # Dest2 - Compare2
bne.b CAS2W2_NOUPDATE
movs.w %d5,(%a1) # Update2[15:0] -> DEST2
bra.b CAS2W2_UPDATE
bra.b ~+16
CAS2W2_UPDATE:
ror.l &0x8,%d4 # get Update1[15:8]
movs.b %d4,(%a0)+ # Update1[15:8] -> DEST1
movc %a3,%buscr # assert LOCKE*
rol.l &0x8,%d4 # get Update1[7:0]
bra.b CAS2W2_UPDATE2
bra.b ~+16
CAS2W2_UPDATE2:
movs.b %d4,(%a0) # Update1[7:0] -> DEST1+0x1
movc %a4,%buscr # unlock the bus
bra.w cas2w_update_done
nop
bra.b ~+16
CAS2W2_NOUPDATE:
ror.l &0x8,%d0 # get Dest1[15:8]
movs.b %d0,(%a0)+ # Dest1[15:8] -> DEST1
movc %a3,%buscr # assert LOCKE*
rol.l &0x8,%d0 # get Dest1[7:0]
bra.b CAS2W2_NOUPDATE2
bra.b ~+16
CAS2W2_NOUPDATE2:
movs.b %d0,(%a0) # Dest1[7:0] -> DEST1+0x1
movc %a4,%buscr # unlock the bus
bra.w cas2w_noupdate_done
nop
bra.b ~+16
CAS2W2_FILLER:
nop
nop
nop
nop
nop
nop
nop
bra.b CAS2W2_START
# ###### ## ######
# # # # #
# # ###### ######
# # # # #
# ###### # # ######
#########################################################################
# XDEF **************************************************************** #
# _isp_cas(): "core" emulation code for the cas instruction #
# #
# XREF **************************************************************** #
# _isp_cas_finish() - only exit point for this emulation code; #
# do clean-up #
# #
# INPUT *************************************************************** #
# *see entry chart below* #
# #
# OUTPUT ************************************************************** #
# *see exit chart below* #
# #
# ALGORITHM *********************************************************** #
# (1) Make several copies of the effective address. #
# (2) Save current SR; Then mask off all maskable interrupts. #
# (3) Save current DFC/SFC (ASSUMED TO BE EQUAL!!!); Then set #
# SFC/DFC according to whether exception occurred in user or #
# supervisor mode. #
# (4) Use "plpaw" instruction to pre-load ATC with effective #
# address page(s). THIS SHOULD NOT FAULT!!! The relevant #
# page(s) should have been made resident prior to entering #
# this routine. #
# (5) Push the operand lines from the cache w/ "cpushl". #
# In the 68040, this was done within the locked region. In #
# the 68060, it is done outside of the locked region. #
# (6) Pre-fetch the core emulation instructions by executing one #
# branch within each physical line (16 bytes) of the code #
# before actually executing the code. #
# (7) Load the BUSCR with the bus lock value. #
# (8) Fetch the source operand. #
# (9) Do the compare. If equal, go to step (12). #
# (10)Unequal. No update occurs. But, we do write the DST op back #
# to itself (as w/ the '040) so we can gracefully unlock #
# the bus (and assert LOCKE*) using BUSCR and the final move. #
# (11)Exit. #
# (12)Write update operand to the DST location. Use BUSCR to #
# assert LOCKE* for the final write operation. #
# (13)Exit. #
# #
# The algorithm is actually implemented slightly differently #
# depending on the size of the operation and the misalignment of the #
# operand. A misaligned operand must be written in aligned chunks or #
# else the BUSCR register control gets confused. #
# #
#########################################################################
#########################################################
# THIS IS THE STATE OF THE INTEGER REGISTER FILE UPON #
# ENTERING _isp_cas(). #
# #
# D0 = xxxxxxxx #
# D1 = xxxxxxxx #
# D2 = update operand #
# D3 = xxxxxxxx #
# D4 = compare operand #
# D5 = xxxxxxxx #
# D6 = supervisor ('xxxxxxff) or user mode ('xxxxxx00) #
# D7 = longword ('xxxxxxff) or word size ('xxxxxx00) #
# A0 = ADDR #
# A1 = xxxxxxxx #
# A2 = xxxxxxxx #
# A3 = xxxxxxxx #
# A4 = xxxxxxxx #
# A5 = xxxxxxxx #
# A6 = frame pointer #
# A7 = stack pointer #
#########################################################
global _isp_cas
_isp_cas:
tst.b %d6 # user or supervisor mode?
bne.b cas_super # supervisor
cas_user:
movq.l &0x1,%d0 # load user data fc
bra.b cas_cont
cas_super:
movq.l &0x5,%d0 # load supervisor data fc
cas_cont:
tst.b %d7 # word or longword?
bne.w casl # longword
####
casw:
mov.l %a0,%a1 # make copy for plpaw1
mov.l %a0,%a2 # make copy for plpaw2
addq.l &0x1,%a2 # plpaw2 points to end of word
mov.l %d2,%d3 # d3 = update[7:0]
lsr.w &0x8,%d2 # d2 = update[15:8]
# mask interrupt levels 0-6. save old mask value.
mov.w %sr,%d7 # save current SR
ori.w &0x0700,%sr # inhibit interrupts
# load the SFC and DFC with the appropriate mode.
movc %sfc,%d6 # save old SFC/DFC
movc %d0,%sfc # load new sfc
movc %d0,%dfc # load new dfc
# pre-load the operand ATC. no page faults should occur here because
# _real_lock_page() should have taken care of this.
plpaw (%a1) # load atc for ADDR
plpaw (%a2) # load atc for ADDR+1
# push the operand lines from the cache if they exist.
cpushl %dc,(%a1) # push dirty data
cpushl %dc,(%a2) # push dirty data
# load the BUSCR values.
mov.l &0x80000000,%a1 # assert LOCK* buscr value
mov.l &0xa0000000,%a2 # assert LOCKE* buscr value
mov.l &0x00000000,%a3 # buscr unlock value
# pre-load the instruction cache for the following algorithm.
# this will minimize the number of cycles that LOCK* will be asserted.
bra.b CASW_ENTER # start pre-loading icache
#
# D0 = dst operand <-
# D1 = update[15:8] operand
# D2 = update[7:0] operand
# D3 = xxxxxxxx
# D4 = compare[15:0] operand
# D5 = xxxxxxxx
# D6 = old SFC/DFC
# D7 = old SR
# A0 = ADDR
# A1 = bus LOCK* value
# A2 = bus LOCKE* value
# A3 = bus unlock value
# A4 = xxxxxxxx
# A5 = xxxxxxxx
#
align 0x10
CASW_START:
movc %a1,%buscr # assert LOCK*
movs.w (%a0),%d0 # fetch Dest[15:0]
cmp.w %d0,%d4 # Dest - Compare
bne.b CASW_NOUPDATE
bra.b CASW_UPDATE
CASW_ENTER:
bra.b ~+16
CASW_UPDATE:
movs.b %d2,(%a0)+ # Update[15:8] -> DEST
movc %a2,%buscr # assert LOCKE*
movs.b %d3,(%a0) # Update[7:0] -> DEST+0x1
bra.b CASW_UPDATE2
bra.b ~+16
CASW_UPDATE2:
movc %a3,%buscr # unlock the bus
bra.b casw_update_done
nop
nop
nop
nop
bra.b ~+16
CASW_NOUPDATE:
ror.l &0x8,%d0 # get Dest[15:8]
movs.b %d0,(%a0)+ # Dest[15:8] -> DEST
movc %a2,%buscr # assert LOCKE*
rol.l &0x8,%d0 # get Dest[7:0]
bra.b CASW_NOUPDATE2
bra.b ~+16
CASW_NOUPDATE2:
movs.b %d0,(%a0) # Dest[7:0] -> DEST+0x1
movc %a3,%buscr # unlock the bus
bra.b casw_noupdate_done
nop
nop
bra.b ~+16
CASW_FILLER:
nop
nop
nop
nop
nop
nop
nop
bra.b CASW_START
#################################################################
# THIS MUST BE THE STATE OF THE INTEGER REGISTER FILE UPON #
# CALLING _isp_cas_finish(). #
# #
# D0 = destination[15:0] operand #
# D1 = 'xxxxxx11 -> no reg update; 'xxxxxx00 -> update required #
# D2 = xxxxxxxx #
# D3 = xxxxxxxx #
# D4 = compare[15:0] operand #
# D5 = xxxxxxxx #
# D6 = xxxxxxxx #
# D7 = xxxxxxxx #
# A0 = xxxxxxxx #
# A1 = xxxxxxxx #
# A2 = xxxxxxxx #
# A3 = xxxxxxxx #
# A4 = xxxxxxxx #
# A5 = xxxxxxxx #
# A6 = frame pointer #
# A7 = stack pointer #
#################################################################
casw_noupdate_done:
# restore previous SFC/DFC value.
movc %d6,%sfc # restore old SFC
movc %d6,%dfc # restore old DFC
# restore previous interrupt mask level.
mov.w %d7,%sr # restore old SR
sf %d1 # indicate no update was done
bra.l _isp_cas_finish
casw_update_done:
# restore previous SFC/DFC value.
movc %d6,%sfc # restore old SFC
movc %d6,%dfc # restore old DFC
# restore previous interrupt mask level.
mov.w %d7,%sr # restore old SR
st %d1 # indicate update was done
bra.l _isp_cas_finish
################
# there are two possible mis-aligned cases for longword cas. they
# are separated because the final write which asserts LOCKE* must
# be an aligned write.
casl:
mov.l %a0,%a1 # make copy for plpaw1
mov.l %a0,%a2 # make copy for plpaw2
addq.l &0x3,%a2 # plpaw2 points to end of longword
mov.l %a0,%d1 # byte or word misaligned?
btst &0x0,%d1
bne.w casl2 # byte misaligned
mov.l %d2,%d3 # d3 = update[15:0]
swap %d2 # d2 = update[31:16]
# mask interrupts levels 0-6. save old mask value.
mov.w %sr,%d7 # save current SR
ori.w &0x0700,%sr # inhibit interrupts
# load the SFC and DFC with the appropriate mode.
movc %sfc,%d6 # save old SFC/DFC
movc %d0,%sfc # load new sfc
movc %d0,%dfc # load new dfc
# pre-load the operand ATC. no page faults should occur here because
# _real_lock_page() should have taken care of this.
plpaw (%a1) # load atc for ADDR
plpaw (%a2) # load atc for ADDR+3
# push the operand lines from the cache if they exist.
cpushl %dc,(%a1) # push dirty data
cpushl %dc,(%a2) # push dirty data
# load the BUSCR values.
mov.l &0x80000000,%a1 # assert LOCK* buscr value
mov.l &0xa0000000,%a2 # assert LOCKE* buscr value
mov.l &0x00000000,%a3 # buscr unlock value
bra.b CASL_ENTER # start pre-loading icache
#
# D0 = dst operand <-
# D1 = xxxxxxxx
# D2 = update[31:16] operand
# D3 = update[15:0] operand
# D4 = compare[31:0] operand
# D5 = xxxxxxxx
# D6 = old SFC/DFC
# D7 = old SR
# A0 = ADDR
# A1 = bus LOCK* value
# A2 = bus LOCKE* value
# A3 = bus unlock value
# A4 = xxxxxxxx
# A5 = xxxxxxxx
#
align 0x10
CASL_START:
movc %a1,%buscr # assert LOCK*
movs.l (%a0),%d0 # fetch Dest[31:0]
cmp.l %d0,%d4 # Dest - Compare
bne.b CASL_NOUPDATE
bra.b CASL_UPDATE
CASL_ENTER:
bra.b ~+16
CASL_UPDATE:
movs.w %d2,(%a0)+ # Update[31:16] -> DEST
movc %a2,%buscr # assert LOCKE*
movs.w %d3,(%a0) # Update[15:0] -> DEST+0x2
bra.b CASL_UPDATE2
bra.b ~+16
CASL_UPDATE2:
movc %a3,%buscr # unlock the bus
bra.b casl_update_done
nop
nop
nop
nop
bra.b ~+16
CASL_NOUPDATE:
swap %d0 # get Dest[31:16]
movs.w %d0,(%a0)+ # Dest[31:16] -> DEST
swap %d0 # get Dest[15:0]
movc %a2,%buscr # assert LOCKE*
bra.b CASL_NOUPDATE2
bra.b ~+16
CASL_NOUPDATE2:
movs.w %d0,(%a0) # Dest[15:0] -> DEST+0x2
movc %a3,%buscr # unlock the bus
bra.b casl_noupdate_done
nop
nop
bra.b ~+16
CASL_FILLER:
nop
nop
nop
nop
nop
nop
nop
bra.b CASL_START
#################################################################
# THIS MUST BE THE STATE OF THE INTEGER REGISTER FILE UPON #
# CALLING _isp_cas_finish(). #
# #
# D0 = destination[31:0] operand #
# D1 = 'xxxxxx11 -> no reg update; 'xxxxxx00 -> update required #
# D2 = xxxxxxxx #
# D3 = xxxxxxxx #
# D4 = compare[31:0] operand #
# D5 = xxxxxxxx #
# D6 = xxxxxxxx #
# D7 = xxxxxxxx #
# A0 = xxxxxxxx #
# A1 = xxxxxxxx #
# A2 = xxxxxxxx #
# A3 = xxxxxxxx #
# A4 = xxxxxxxx #
# A5 = xxxxxxxx #
# A6 = frame pointer #
# A7 = stack pointer #
#################################################################
casl_noupdate_done:
# restore previous SFC/DFC value.
movc %d6,%sfc # restore old SFC
movc %d6,%dfc # restore old DFC
# restore previous interrupt mask level.
mov.w %d7,%sr # restore old SR
sf %d1 # indicate no update was done
bra.l _isp_cas_finish
casl_update_done:
# restore previous SFC/DFC value.
movc %d6,%sfc # restore old SFC
movc %d6,%dfc # restore old DFC
# restore previous interrupts mask level.
mov.w %d7,%sr # restore old SR
st %d1 # indicate update was done
bra.l _isp_cas_finish
#######################################
casl2:
mov.l %d2,%d5 # d5 = Update[7:0]
lsr.l &0x8,%d2
mov.l %d2,%d3 # d3 = Update[23:8]
swap %d2 # d2 = Update[31:24]
# mask interrupts levels 0-6. save old mask value.
mov.w %sr,%d7 # save current SR
ori.w &0x0700,%sr # inhibit interrupts
# load the SFC and DFC with the appropriate mode.
movc %sfc,%d6 # save old SFC/DFC
movc %d0,%sfc # load new sfc
movc %d0,%dfc # load new dfc
# pre-load the operand ATC. no page faults should occur here because
# _real_lock_page() should have taken care of this already.
plpaw (%a1) # load atc for ADDR
plpaw (%a2) # load atc for ADDR+3
# puch the operand lines from the cache if they exist.
cpushl %dc,(%a1) # push dirty data
cpushl %dc,(%a2) # push dirty data
# load the BUSCR values.
mov.l &0x80000000,%a1 # assert LOCK* buscr value
mov.l &0xa0000000,%a2 # assert LOCKE* buscr value
mov.l &0x00000000,%a3 # buscr unlock value
# pre-load the instruction cache for the following algorithm.
# this will minimize the number of cycles that LOCK* will be asserted.
bra.b CASL2_ENTER # start pre-loading icache
#
# D0 = dst operand <-
# D1 = xxxxxxxx
# D2 = update[31:24] operand
# D3 = update[23:8] operand
# D4 = compare[31:0] operand
# D5 = update[7:0] operand
# D6 = old SFC/DFC
# D7 = old SR
# A0 = ADDR
# A1 = bus LOCK* value
# A2 = bus LOCKE* value
# A3 = bus unlock value
# A4 = xxxxxxxx
# A5 = xxxxxxxx
#
align 0x10
CASL2_START:
movc %a1,%buscr # assert LOCK*
movs.l (%a0),%d0 # fetch Dest[31:0]
cmp.l %d0,%d4 # Dest - Compare
bne.b CASL2_NOUPDATE
bra.b CASL2_UPDATE
CASL2_ENTER:
bra.b ~+16
CASL2_UPDATE:
movs.b %d2,(%a0)+ # Update[31:24] -> DEST
movs.w %d3,(%a0)+ # Update[23:8] -> DEST+0x1
movc %a2,%buscr # assert LOCKE*
bra.b CASL2_UPDATE2
bra.b ~+16
CASL2_UPDATE2:
movs.b %d5,(%a0) # Update[7:0] -> DEST+0x3
movc %a3,%buscr # unlock the bus
bra.w casl_update_done
nop
bra.b ~+16
CASL2_NOUPDATE:
rol.l &0x8,%d0 # get Dest[31:24]
movs.b %d0,(%a0)+ # Dest[31:24] -> DEST
swap %d0 # get Dest[23:8]
movs.w %d0,(%a0)+ # Dest[23:8] -> DEST+0x1
bra.b CASL2_NOUPDATE2
bra.b ~+16
CASL2_NOUPDATE2:
rol.l &0x8,%d0 # get Dest[7:0]
movc %a2,%buscr # assert LOCKE*
movs.b %d0,(%a0) # Dest[7:0] -> DEST+0x3
bra.b CASL2_NOUPDATE3
nop
bra.b ~+16
CASL2_NOUPDATE3:
movc %a3,%buscr # unlock the bus
bra.w casl_noupdate_done
nop
nop
nop
bra.b ~+16
CASL2_FILLER:
nop
nop
nop
nop
nop
nop
nop
bra.b CASL2_START
####
####
# end label used by _isp_cas_inrange()
global _CASHI
_CASHI: