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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 | /*---------------------------------------------------------------------------+ | 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() { (fp_etc_table[FPU_rm])(&st(0), FPU_gettag0()); } |