// SPDX-License-Identifier: GPL-2.0 /*---------------------------------------------------------------------------+ | fpu_etc.c | | | | Implement a few FPU instructions. | | | | Copyright (C) 1992,1993,1994,1997 | | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, | | Australia. E-mail billm@suburbia.net | | | | | +---------------------------------------------------------------------------*/ #include "fpu_system.h" #include "exception.h" #include "fpu_emu.h" #include "status_w.h" #include "reg_constant.h" static void fchs(FPU_REG *st0_ptr, u_char st0tag) { if (st0tag ^ TAG_Empty) { signbyte(st0_ptr) ^= SIGN_NEG; clear_C1(); } else FPU_stack_underflow(); } static void fabs(FPU_REG *st0_ptr, u_char st0tag) { if (st0tag ^ TAG_Empty) { setpositive(st0_ptr); clear_C1(); } else FPU_stack_underflow(); } static void ftst_(FPU_REG *st0_ptr, u_char st0tag) { switch (st0tag) { case TAG_Zero: setcc(SW_C3); break; case TAG_Valid: if (getsign(st0_ptr) == SIGN_POS) setcc(0); else setcc(SW_C0); break; case TAG_Special: switch (FPU_Special(st0_ptr)) { case TW_Denormal: if (getsign(st0_ptr) == SIGN_POS) setcc(0); else setcc(SW_C0); if (denormal_operand() < 0) { #ifdef PECULIAR_486 /* This is weird! */ if (getsign(st0_ptr) == SIGN_POS) setcc(SW_C3); #endif /* PECULIAR_486 */ return; } break; case TW_NaN: setcc(SW_C0 | SW_C2 | SW_C3); /* Operand is not comparable */ EXCEPTION(EX_Invalid); break; case TW_Infinity: if (getsign(st0_ptr) == SIGN_POS) setcc(0); else setcc(SW_C0); break; default: setcc(SW_C0 | SW_C2 | SW_C3); /* Operand is not comparable */ EXCEPTION(EX_INTERNAL | 0x14); break; } break; case TAG_Empty: setcc(SW_C0 | SW_C2 | SW_C3); EXCEPTION(EX_StackUnder); break; } } static void fxam(FPU_REG *st0_ptr, u_char st0tag) { int c = 0; switch (st0tag) { case TAG_Empty: c = SW_C3 | SW_C0; break; case TAG_Zero: c = SW_C3; break; case TAG_Valid: c = SW_C2; break; case TAG_Special: switch (FPU_Special(st0_ptr)) { case TW_Denormal: c = SW_C2 | SW_C3; /* Denormal */ break; case TW_NaN: /* We also use NaN for unsupported types. */ if ((st0_ptr->sigh & 0x80000000) && (exponent(st0_ptr) == EXP_OVER)) c = SW_C0; break; case TW_Infinity: c = SW_C2 | SW_C0; break; } } if (getsign(st0_ptr) == SIGN_NEG) c |= SW_C1; setcc(c); } static FUNC_ST0 const fp_etc_table[] = { fchs, fabs, (FUNC_ST0) FPU_illegal, (FUNC_ST0) FPU_illegal, ftst_, fxam, (FUNC_ST0) FPU_illegal, (FUNC_ST0) FPU_illegal }; void FPU_etc(void) { (fp_etc_table[FPU_rm]) (&st(0), FPU_gettag0()); }
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