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 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 f2xm1(FPU_REG *st0_ptr, u_char tag) { FPU_REG a; clear_C1(); if ( tag == TAG_Valid ) { /* For an 80486 FPU, the result is undefined if the arg is >= 1.0 */ if ( exponent(st0_ptr) < 0 ) { denormal_arg: FPU_to_exp16(st0_ptr, &a); /* poly_2xm1(x) requires 0 < st(0) < 1. */ poly_2xm1(getsign(st0_ptr), &a, st0_ptr); } set_precision_flag_up(); /* 80486 appears to always do this */ return; } if ( tag == TAG_Zero ) return; if ( tag == TAG_Special ) tag = FPU_Special(st0_ptr); switch ( tag ) { case TW_Denormal: if ( denormal_operand() < 0 ) return; goto denormal_arg; case TW_Infinity: if ( signnegative(st0_ptr) ) { /* -infinity gives -1 (p16-10) */ FPU_copy_to_reg0(&CONST_1, TAG_Valid); setnegative(st0_ptr); } return; default: single_arg_error(st0_ptr, tag); } }
static void f2xm1(FPU_REG *st0_ptr, u_char tag) { FPU_REG a; clear_C1(); if (tag == TAG_Valid) { if (exponent(st0_ptr) < 0) { denormal_arg: FPU_to_exp16(st0_ptr, &a); poly_2xm1(getsign(st0_ptr), &a, st0_ptr); } set_precision_flag_up(); return; } if (tag == TAG_Zero) return; if (tag == TAG_Special) tag = FPU_Special(st0_ptr); switch (tag) { case TW_Denormal: if (denormal_operand() < 0) return; goto denormal_arg; case TW_Infinity: if (signnegative(st0_ptr)) { FPU_copy_to_reg0(&CONST_1, TAG_Valid); setnegative(st0_ptr); } return; default: single_arg_error(st0_ptr, tag); } }
static void fxtract(FPU_REG *st0_ptr, u_char st0_tag) { FPU_REG *st_new_ptr; u_char sign; register FPU_REG *st1_ptr = st0_ptr; if (STACK_OVERFLOW) { FPU_stack_overflow(); return; } clear_C1(); if (st0_tag == TAG_Valid) { long e; push(); sign = getsign(st1_ptr); reg_copy(st1_ptr, st_new_ptr); setexponent16(st_new_ptr, exponent(st_new_ptr)); denormal_arg: e = exponent16(st_new_ptr); convert_l2reg(&e, 1); setexponentpos(st_new_ptr, 0); setsign(st_new_ptr, sign); FPU_settag0(TAG_Valid); return; } else if (st0_tag == TAG_Zero) { sign = getsign(st0_ptr); if (FPU_divide_by_zero(0, SIGN_NEG) < 0) return; push(); FPU_copy_to_reg0(&CONST_Z, TAG_Zero); setsign(st_new_ptr, sign); return; } if (st0_tag == TAG_Special) st0_tag = FPU_Special(st0_ptr); if (st0_tag == TW_Denormal) { if (denormal_operand() < 0) return; push(); sign = getsign(st1_ptr); FPU_to_exp16(st1_ptr, st_new_ptr); goto denormal_arg; } else if (st0_tag == TW_Infinity) { sign = getsign(st0_ptr); setpositive(st0_ptr); push(); FPU_copy_to_reg0(&CONST_INF, TAG_Special); setsign(st_new_ptr, sign); return; } else if (st0_tag == TW_NaN) { if (real_1op_NaN(st0_ptr) < 0) return; push(); FPU_copy_to_reg0(st0_ptr, TAG_Special); return; } else if (st0_tag == TAG_Empty) { if (control_word & EX_Invalid) { FPU_stack_underflow(); push(); FPU_stack_underflow(); } else EXCEPTION(EX_StackUnder); } #ifdef PARANOID else EXCEPTION(EX_INTERNAL | 0x119); #endif }
static void fptan(FPU_REG *st0_ptr, u_char st0_tag) { FPU_REG *st_new_ptr; int q; u_char arg_sign = getsign(st0_ptr); if (st0_tag == TAG_Empty) { FPU_stack_underflow(); if (control_word & CW_Invalid) { st_new_ptr = &st(-1); push(); FPU_stack_underflow(); } return; } if (STACK_OVERFLOW) { FPU_stack_overflow(); return; } if (st0_tag == TAG_Valid) { if (exponent(st0_ptr) > -40) { if ((q = trig_arg(st0_ptr, 0)) == -1) { return; } poly_tan(st0_ptr); setsign(st0_ptr, (q & 1) ^ (arg_sign != 0)); set_precision_flag_up(); } else { denormal_arg: FPU_to_exp16(st0_ptr, st0_ptr); st0_tag = FPU_round(st0_ptr, 1, 0, FULL_PRECISION, arg_sign); FPU_settag0(st0_tag); } push(); FPU_copy_to_reg0(&CONST_1, TAG_Valid); return; } if (st0_tag == TAG_Zero) { push(); FPU_copy_to_reg0(&CONST_1, TAG_Valid); setcc(0); return; } if (st0_tag == TAG_Special) st0_tag = FPU_Special(st0_ptr); if (st0_tag == TW_Denormal) { if (denormal_operand() < 0) return; goto denormal_arg; } if (st0_tag == TW_Infinity) { if (arith_invalid(0) >= 0) { st_new_ptr = &st(-1); push(); arith_invalid(0); } return; } single_arg_2_error(st0_ptr, st0_tag); }
int FPU_add(FPU_REG const *b, u_char tagb, int deststnr, int control_w) { FPU_REG *a = &st(0); FPU_REG *dest = &st(deststnr); u_char signb = getsign(b); u_char taga = FPU_gettag0(); u_char signa = getsign(a); u_char saved_sign = getsign(dest); int diff, tag, expa, expb; if (!(taga | tagb)) { expa = exponent(a); expb = exponent(b); valid_add: if (!(signa ^ signb)) { tag = FPU_u_add(a, b, dest, control_w, signa, expa, expb); } else { diff = expa - expb; if (!diff) { diff = a->sigh - b->sigh; if (!diff) { diff = a->sigl > b->sigl; if (!diff) diff = -(a->sigl < b->sigl); } } if (diff > 0) { tag = FPU_u_sub(a, b, dest, control_w, signa, expa, expb); } else if (diff < 0) { tag = FPU_u_sub(b, a, dest, control_w, signb, expb, expa); } else { FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr); setsign(dest, ((control_w & CW_RC) != RC_DOWN) ? SIGN_POS : SIGN_NEG); return TAG_Zero; } } if (tag < 0) { setsign(dest, saved_sign); return tag; } FPU_settagi(deststnr, tag); return tag; } if (taga == TAG_Special) taga = FPU_Special(a); if (tagb == TAG_Special) tagb = FPU_Special(b); if (((taga == TAG_Valid) && (tagb == TW_Denormal)) || ((taga == TW_Denormal) && (tagb == TAG_Valid)) || ((taga == TW_Denormal) && (tagb == TW_Denormal))) { FPU_REG x, y; if (denormal_operand() < 0) return FPU_Exception; FPU_to_exp16(a, &x); FPU_to_exp16(b, &y); a = &x; b = &y; expa = exponent16(a); expb = exponent16(b); goto valid_add; } if ((taga == TW_NaN) || (tagb == TW_NaN)) { if (deststnr == 0) return real_2op_NaN(b, tagb, deststnr, a); else return real_2op_NaN(a, taga, deststnr, a); } return add_sub_specials(a, taga, signa, b, tagb, signb, dest, deststnr, control_w); }
int FPU_sub(int flags, int rm, int control_w) { FPU_REG const *a, *b; FPU_REG *dest; u_char taga, tagb, signa, signb, saved_sign, sign; int diff, tag = 0, expa, expb, deststnr; a = &st(0); taga = FPU_gettag0(); deststnr = 0; if (flags & LOADED) { b = (FPU_REG *) rm; tagb = flags & 0x0f; } else { b = &st(rm); tagb = FPU_gettagi(rm); if (flags & DEST_RM) deststnr = rm; } signa = getsign(a); signb = getsign(b); if (flags & REV) { signa ^= SIGN_NEG; signb ^= SIGN_NEG; } dest = &st(deststnr); saved_sign = getsign(dest); if (!(taga | tagb)) { expa = exponent(a); expb = exponent(b); valid_subtract: diff = expa - expb; if (!diff) { diff = a->sigh - b->sigh; if (!diff) { diff = a->sigl > b->sigl; if (!diff) diff = -(a->sigl < b->sigl); } } switch ((((int)signa) * 2 + signb) / SIGN_NEG) { case 0: case 3: if (diff > 0) { tag = FPU_u_sub(a, b, dest, control_w, signa, expa, expb); } else if (diff == 0) { FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr); setsign(dest, ((control_w & CW_RC) != RC_DOWN) ? SIGN_POS : SIGN_NEG); return TAG_Zero; } else { sign = signa ^ SIGN_NEG; tag = FPU_u_sub(b, a, dest, control_w, sign, expb, expa); } break; case 1: tag = FPU_u_add(a, b, dest, control_w, SIGN_POS, expa, expb); break; case 2: tag = FPU_u_add(a, b, dest, control_w, SIGN_NEG, expa, expb); break; #ifdef PARANOID default: EXCEPTION(EX_INTERNAL | 0x111); return -1; #endif } if (tag < 0) { setsign(dest, saved_sign); return tag; } FPU_settagi(deststnr, tag); return tag; } if (taga == TAG_Special) taga = FPU_Special(a); if (tagb == TAG_Special) tagb = FPU_Special(b); if (((taga == TAG_Valid) && (tagb == TW_Denormal)) || ((taga == TW_Denormal) && (tagb == TAG_Valid)) || ((taga == TW_Denormal) && (tagb == TW_Denormal))) { FPU_REG x, y; if (denormal_operand() < 0) return FPU_Exception; FPU_to_exp16(a, &x); FPU_to_exp16(b, &y); a = &x; b = &y; expa = exponent16(a); expb = exponent16(b); goto valid_subtract; } if ((taga == TW_NaN) || (tagb == TW_NaN)) { FPU_REG const *d1, *d2; if (flags & REV) { d1 = b; d2 = a; } else { d1 = a; d2 = b; } if (flags & LOADED) return real_2op_NaN(b, tagb, deststnr, d1); if (flags & DEST_RM) return real_2op_NaN(a, taga, deststnr, d2); else return real_2op_NaN(b, tagb, deststnr, d2); } return add_sub_specials(a, taga, signa, b, tagb, signb ^ SIGN_NEG, dest, deststnr, control_w); }
static void fptan(FPU_REG *st0_ptr, u_char st0_tag) { FPU_REG *st_new_ptr; int q; u_char arg_sign = getsign(st0_ptr); /* Stack underflow has higher priority */ if (st0_tag == TAG_Empty) { FPU_stack_underflow(); /* Puts a QNaN in st(0) */ if (control_word & CW_Invalid) { st_new_ptr = &st(-1); push(); FPU_stack_underflow(); /* Puts a QNaN in the new st(0) */ } return; } if (STACK_OVERFLOW) { FPU_stack_overflow(); return; } if (st0_tag == TAG_Valid) { if (exponent(st0_ptr) > -40) { if ((q = trig_arg(st0_ptr, 0)) == -1) { /* Operand is out of range */ return; } poly_tan(st0_ptr); setsign(st0_ptr, (q & 1) ^ (arg_sign != 0)); set_precision_flag_up(); /* We do not really know if up or down */ } else { /* For a small arg, the result == the argument */ /* Underflow may happen */ denormal_arg: FPU_to_exp16(st0_ptr, st0_ptr); st0_tag = FPU_round(st0_ptr, 1, 0, FULL_PRECISION, arg_sign); FPU_settag0(st0_tag); } push(); FPU_copy_to_reg0(&CONST_1, TAG_Valid); return; } if (st0_tag == TAG_Zero) { push(); FPU_copy_to_reg0(&CONST_1, TAG_Valid); setcc(0); return; } if (st0_tag == TAG_Special) st0_tag = FPU_Special(st0_ptr); if (st0_tag == TW_Denormal) { if (denormal_operand() < 0) return; goto denormal_arg; } if (st0_tag == TW_Infinity) { /* The 80486 treats infinity as an invalid operand */ if (arith_invalid(0) >= 0) { st_new_ptr = &st(-1); push(); arith_invalid(0); } return; } single_arg_2_error(st0_ptr, st0_tag); }
/* Divide one register by another and put the result into a third register. */ int FPU_div(int flags, int rm, int control_w) { FPU_REG x, y; FPU_REG const *a, *b, *st0_ptr, *st_ptr; FPU_REG *dest; u_char taga, tagb, signa, signb, sign, saved_sign; int tag, deststnr; if (flags & DEST_RM) deststnr = rm; else deststnr = 0; if (flags & REV) { b = &st(0); st0_ptr = b; tagb = FPU_gettag0(); if (flags & LOADED) { a = (FPU_REG *) rm; taga = flags & 0x0f; } else { a = &st(rm); st_ptr = a; taga = FPU_gettagi(rm); } } else { a = &st(0); st0_ptr = a; taga = FPU_gettag0(); if (flags & LOADED) { b = (FPU_REG *) rm; tagb = flags & 0x0f; } else { b = &st(rm); st_ptr = b; tagb = FPU_gettagi(rm); } } signa = getsign(a); signb = getsign(b); sign = signa ^ signb; dest = &st(deststnr); saved_sign = getsign(dest); if (!(taga | tagb)) { /* Both regs Valid, this should be the most common case. */ reg_copy(a, &x); reg_copy(b, &y); setpositive(&x); setpositive(&y); tag = FPU_u_div(&x, &y, dest, control_w, sign); if (tag < 0) return tag; FPU_settagi(deststnr, tag); return tag; } if (taga == TAG_Special) taga = FPU_Special(a); if (tagb == TAG_Special) tagb = FPU_Special(b); if (((taga == TAG_Valid) && (tagb == TW_Denormal)) || ((taga == TW_Denormal) && (tagb == TAG_Valid)) || ((taga == TW_Denormal) && (tagb == TW_Denormal))) { if (denormal_operand() < 0) return FPU_Exception; FPU_to_exp16(a, &x); FPU_to_exp16(b, &y); tag = FPU_u_div(&x, &y, dest, control_w, sign); if (tag < 0) return tag; FPU_settagi(deststnr, tag); return tag; } else if ((taga <= TW_Denormal) && (tagb <= TW_Denormal)) { if (tagb != TAG_Zero) { /* Want to find Zero/Valid */ if (tagb == TW_Denormal) { if (denormal_operand() < 0) return FPU_Exception; } /* The result is zero. */ FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr); setsign(dest, sign); return TAG_Zero; } /* We have an exception condition, either 0/0 or Valid/Zero. */ if (taga == TAG_Zero) { /* 0/0 */ return arith_invalid(deststnr); } /* Valid/Zero */ return FPU_divide_by_zero(deststnr, sign); } /* Must have infinities, NaNs, etc */ else if ((taga == TW_NaN) || (tagb == TW_NaN)) { if (flags & LOADED) return real_2op_NaN((FPU_REG *) rm, flags & 0x0f, 0, st0_ptr); if (flags & DEST_RM) { int tag; tag = FPU_gettag0(); if (tag == TAG_Special) tag = FPU_Special(st0_ptr); return real_2op_NaN(st0_ptr, tag, rm, (flags & REV) ? st0_ptr : &st(rm)); } else { int tag; tag = FPU_gettagi(rm); if (tag == TAG_Special) tag = FPU_Special(&st(rm)); return real_2op_NaN(&st(rm), tag, 0, (flags & REV) ? st0_ptr : &st(rm)); } } else if (taga == TW_Infinity) { if (tagb == TW_Infinity) { /* infinity/infinity */ return arith_invalid(deststnr); } else { /* tagb must be Valid or Zero */ if ((tagb == TW_Denormal) && (denormal_operand() < 0)) return FPU_Exception; /* Infinity divided by Zero or Valid does not raise and exception, but returns Infinity */ FPU_copy_to_regi(a, TAG_Special, deststnr); setsign(dest, sign); return taga; } } else if (tagb == TW_Infinity) { if ((taga == TW_Denormal) && (denormal_operand() < 0)) return FPU_Exception; /* The result is zero. */ FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr); setsign(dest, sign); return TAG_Zero; } #ifdef PARANOID else { EXCEPTION(EX_INTERNAL | 0x102); return FPU_Exception; } #endif /* PARANOID */ return 0; }
int FPU_mul(FPU_REG const *b, u_char tagb, int deststnr, int control_w) { FPU_REG *a = &st(deststnr); FPU_REG *dest = a; u_char taga = FPU_gettagi(deststnr); u_char saved_sign = getsign(dest); u_char sign = (getsign(a) ^ getsign(b)); int tag; if (!(taga | tagb)) { tag = FPU_u_mul(a, b, dest, control_w, sign, exponent(a) + exponent(b)); if (tag < 0) { setsign(dest, saved_sign); return tag; } FPU_settagi(deststnr, tag); return tag; } if (taga == TAG_Special) taga = FPU_Special(a); if (tagb == TAG_Special) tagb = FPU_Special(b); if (((taga == TAG_Valid) && (tagb == TW_Denormal)) || ((taga == TW_Denormal) && (tagb == TAG_Valid)) || ((taga == TW_Denormal) && (tagb == TW_Denormal))) { FPU_REG x, y; if (denormal_operand() < 0) return FPU_Exception; FPU_to_exp16(a, &x); FPU_to_exp16(b, &y); tag = FPU_u_mul(&x, &y, dest, control_w, sign, exponent16(&x) + exponent16(&y)); if (tag < 0) { setsign(dest, saved_sign); return tag; } FPU_settagi(deststnr, tag); return tag; } else if ((taga <= TW_Denormal) && (tagb <= TW_Denormal)) { if (((tagb == TW_Denormal) || (taga == TW_Denormal)) && (denormal_operand() < 0)) return FPU_Exception; FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr); setsign(dest, sign); return TAG_Zero; } else if ((taga == TW_NaN) || (tagb == TW_NaN)) { return real_2op_NaN(b, tagb, deststnr, &st(0)); } else if (((taga == TW_Infinity) && (tagb == TAG_Zero)) || ((tagb == TW_Infinity) && (taga == TAG_Zero))) { return arith_invalid(deststnr); } else if (((taga == TW_Denormal) || (tagb == TW_Denormal)) && (denormal_operand() < 0)) { return FPU_Exception; } else if (taga == TW_Infinity) { FPU_copy_to_regi(a, TAG_Special, deststnr); setsign(dest, sign); return TAG_Special; } else if (tagb == TW_Infinity) { FPU_copy_to_regi(b, TAG_Special, deststnr); setsign(dest, sign); return TAG_Special; } #ifdef PARANOID else { EXCEPTION(EX_INTERNAL | 0x102); return FPU_Exception; } #endif return 0; }
static int compare(FPU_REG const *b, int tagb) { int diff, exp0, expb; u_char st0_tag; FPU_REG *st0_ptr; FPU_REG x, y; u_char st0_sign, signb = getsign(b); st0_ptr = &st(0); st0_tag = FPU_gettag0(); st0_sign = getsign(st0_ptr); if (tagb == TAG_Special) tagb = FPU_Special(b); if (st0_tag == TAG_Special) st0_tag = FPU_Special(st0_ptr); if (((st0_tag != TAG_Valid) && (st0_tag != TW_Denormal)) || ((tagb != TAG_Valid) && (tagb != TW_Denormal))) { if (st0_tag == TAG_Zero) { if (tagb == TAG_Zero) return COMP_A_eq_B; if (tagb == TAG_Valid) return ((signb == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B); if (tagb == TW_Denormal) return ((signb == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B) | COMP_Denormal; } else if (tagb == TAG_Zero) { if (st0_tag == TAG_Valid) return ((st0_sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B); if (st0_tag == TW_Denormal) return ((st0_sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B) | COMP_Denormal; } if (st0_tag == TW_Infinity) { if ((tagb == TAG_Valid) || (tagb == TAG_Zero)) return ((st0_sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B); else if (tagb == TW_Denormal) return ((st0_sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B) | COMP_Denormal; else if (tagb == TW_Infinity) { /* */ return (st0_sign == signb) ? COMP_A_eq_B : ((st0_sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B); } /* */ } else if (tagb == TW_Infinity) { if ((st0_tag == TAG_Valid) || (st0_tag == TAG_Zero)) return ((signb == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B); if (st0_tag == TW_Denormal) return ((signb == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B) | COMP_Denormal; /* */ } /* */ if ((st0_tag == TW_NaN) || (tagb == TW_NaN)) { int signalling = 0, unsupported = 0; if (st0_tag == TW_NaN) { signalling = (st0_ptr->sigh & 0xc0000000) == 0x80000000; unsupported = !((exponent(st0_ptr) == EXP_OVER) && (st0_ptr-> sigh & 0x80000000)); } if (tagb == TW_NaN) { signalling |= (b->sigh & 0xc0000000) == 0x80000000; unsupported |= !((exponent(b) == EXP_OVER) && (b->sigh & 0x80000000)); } if (signalling || unsupported) return COMP_No_Comp | COMP_SNaN | COMP_NaN; else /* */ return COMP_No_Comp | COMP_NaN; } EXCEPTION(EX_Invalid); } if (st0_sign != signb) { return ((st0_sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B) | (((st0_tag == TW_Denormal) || (tagb == TW_Denormal)) ? COMP_Denormal : 0); } if ((st0_tag == TW_Denormal) || (tagb == TW_Denormal)) { FPU_to_exp16(st0_ptr, &x); FPU_to_exp16(b, &y); st0_ptr = &x; b = &y; exp0 = exponent16(st0_ptr); expb = exponent16(b); } else { exp0 = exponent(st0_ptr); expb = exponent(b); } #ifdef PARANOID if (!(st0_ptr->sigh & 0x80000000)) EXCEPTION(EX_Invalid); if (!(b->sigh & 0x80000000)) EXCEPTION(EX_Invalid); #endif /* */ diff = exp0 - expb; if (diff == 0) { diff = st0_ptr->sigh - b->sigh; /* */ if (diff == 0) { diff = st0_ptr->sigl > b->sigl; if (diff == 0) diff = -(st0_ptr->sigl < b->sigl); } } if (diff > 0) { return ((st0_sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B) | (((st0_tag == TW_Denormal) || (tagb == TW_Denormal)) ? COMP_Denormal : 0); } if (diff < 0) { return ((st0_sign == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B) | (((st0_tag == TW_Denormal) || (tagb == TW_Denormal)) ? COMP_Denormal : 0); } return COMP_A_eq_B | (((st0_tag == TW_Denormal) || (tagb == TW_Denormal)) ? COMP_Denormal : 0); }
/* Operates on st(0) and st(n), or on st(0) and temporary data. The destination must be one of the source st(x). */ int FPU_add(FPU_REG const *b, u_char tagb, int deststnr, u16 control_w) { FPU_REG *a = &st(0); FPU_REG *dest = &st(deststnr); u_char signb = getsign(b); u_char taga = FPU_gettag0(); u_char signa = getsign(a); u_char saved_sign = getsign(dest); int diff, tag, expa, expb; if ( !(taga | tagb) ) { expa = exponent(a); expb = exponent(b); valid_add: /* Both registers are valid */ if (!(signa ^ signb)) { /* signs are the same */ tag = FPU_u_add(a, b, dest, control_w, signa, expa, expb); } else { /* The signs are different, so do a subtraction */ diff = expa - expb; if (!diff) { diff = a->sigh - b->sigh; /* This works only if the ms bits are identical. */ if (!diff) { diff = a->sigl > b->sigl; if (!diff) diff = -(a->sigl < b->sigl); } } if (diff > 0) { tag = FPU_u_sub(a, b, dest, control_w, signa, expa, expb); } else if ( diff < 0 ) { tag = FPU_u_sub(b, a, dest, control_w, signb, expb, expa); } else { FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr); /* sign depends upon rounding mode */ setsign(dest, ((control_w & CW_RC) != RC_DOWN) ? SIGN_POS : SIGN_NEG); return TAG_Zero; } } if ( tag < 0 ) { setsign(dest, saved_sign); return tag; } FPU_settagi(deststnr, tag); return tag; } if ( taga == TAG_Special ) taga = FPU_Special(a); if ( tagb == TAG_Special ) tagb = FPU_Special(b); if ( ((taga == TAG_Valid) && (tagb == TW_Denormal)) || ((taga == TW_Denormal) && (tagb == TAG_Valid)) || ((taga == TW_Denormal) && (tagb == TW_Denormal)) ) { FPU_REG x, y; if ( denormal_operand() < 0 ) return FPU_Exception; FPU_to_exp16(a, &x); FPU_to_exp16(b, &y); a = &x; b = &y; expa = exponent16(a); expb = exponent16(b); goto valid_add; } if ( (taga == TW_NaN) || (tagb == TW_NaN) ) { if ( deststnr == 0 ) return real_2op_NaN(b, tagb, deststnr, a); else return real_2op_NaN(a, taga, deststnr, a); } return add_sub_specials(a, taga, signa, b, tagb, signb, dest, deststnr, control_w); }
int FPU_div(int flags, int rm, int control_w) { FPU_REG x, y; FPU_REG const *a, *b, *st0_ptr, *st_ptr; FPU_REG *dest; u_char taga, tagb, signa, signb, sign, saved_sign; int tag, deststnr; if (flags & DEST_RM) deststnr = rm; else deststnr = 0; if (flags & REV) { b = &st(0); st0_ptr = b; tagb = FPU_gettag0(); if (flags & LOADED) { a = (FPU_REG *) rm; taga = flags & 0x0f; } else { a = &st(rm); st_ptr = a; taga = FPU_gettagi(rm); } } else { a = &st(0); st0_ptr = a; taga = FPU_gettag0(); if (flags & LOADED) { b = (FPU_REG *) rm; tagb = flags & 0x0f; } else { b = &st(rm); st_ptr = b; tagb = FPU_gettagi(rm); } } signa = getsign(a); signb = getsign(b); sign = signa ^ signb; dest = &st(deststnr); saved_sign = getsign(dest); if (!(taga | tagb)) { reg_copy(a, &x); reg_copy(b, &y); setpositive(&x); setpositive(&y); tag = FPU_u_div(&x, &y, dest, control_w, sign); if (tag < 0) return tag; FPU_settagi(deststnr, tag); return tag; } if (taga == TAG_Special) taga = FPU_Special(a); if (tagb == TAG_Special) tagb = FPU_Special(b); if (((taga == TAG_Valid) && (tagb == TW_Denormal)) || ((taga == TW_Denormal) && (tagb == TAG_Valid)) || ((taga == TW_Denormal) && (tagb == TW_Denormal))) { if (denormal_operand() < 0) return FPU_Exception; FPU_to_exp16(a, &x); FPU_to_exp16(b, &y); tag = FPU_u_div(&x, &y, dest, control_w, sign); if (tag < 0) return tag; FPU_settagi(deststnr, tag); return tag; } else if ((taga <= TW_Denormal) && (tagb <= TW_Denormal)) { if (tagb != TAG_Zero) { if (tagb == TW_Denormal) { if (denormal_operand() < 0) return FPU_Exception; } FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr); setsign(dest, sign); return TAG_Zero; } if (taga == TAG_Zero) { return arith_invalid(deststnr); } return FPU_divide_by_zero(deststnr, sign); } else if ((taga == TW_NaN) || (tagb == TW_NaN)) { if (flags & LOADED) return real_2op_NaN((FPU_REG *) rm, flags & 0x0f, 0, st0_ptr); if (flags & DEST_RM) { int tag; tag = FPU_gettag0(); if (tag == TAG_Special) tag = FPU_Special(st0_ptr); return real_2op_NaN(st0_ptr, tag, rm, (flags & REV) ? st0_ptr : &st(rm)); } else { int tag; tag = FPU_gettagi(rm); if (tag == TAG_Special) tag = FPU_Special(&st(rm)); return real_2op_NaN(&st(rm), tag, 0, (flags & REV) ? st0_ptr : &st(rm)); } } else if (taga == TW_Infinity) { if (tagb == TW_Infinity) { return arith_invalid(deststnr); } else { if ((tagb == TW_Denormal) && (denormal_operand() < 0)) return FPU_Exception; FPU_copy_to_regi(a, TAG_Special, deststnr); setsign(dest, sign); return taga; } } else if (tagb == TW_Infinity) { if ((taga == TW_Denormal) && (denormal_operand() < 0)) return FPU_Exception; FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr); setsign(dest, sign); return TAG_Zero; } #ifdef PARANOID else { EXCEPTION(EX_INTERNAL | 0x102); return FPU_Exception; } #endif return 0; }