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Fixed denormal operand handling for add/sub instructions

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This commit is contained in:
Stanislav Shwartsman 2003-05-26 19:00:19 +00:00
parent 0cb847f6d3
commit ab3320c6eb
1 changed files with 50 additions and 30 deletions
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80
bochs/cpu/softfloat.cc
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@ -851,13 +851,6 @@ static float32 addFloat32Sigs(float32 a, float32 b, flag zSign, float_status_t &
bSig = extractFloat32Frac(b);
bExp = extractFloat32Exp(b);
if ((aExp == 0) && aSig) {
float_raise(status, float_flag_denormal);
}
if ((bExp == 0) && bSig) {
float_raise(status, float_flag_denormal);
}
expDiff = aExp - bExp;
aSig <<= 6;
bSig <<= 6;
@ -865,9 +858,14 @@ static float32 addFloat32Sigs(float32 a, float32 b, flag zSign, float_status_t &
if (0 < expDiff) {
if (aExp == 0xFF) {
if (aSig) return propagateFloat32NaN(a, b, status);
if (bSig && (bExp == 0)) float_raise(status, float_flag_denormal);
return a;
}
if ((aExp == 0) && aSig) {
float_raise(status, float_flag_denormal);
}
if (bExp == 0) {
if (bSig) float_raise(status, float_flag_denormal);
--expDiff;
}
else {
@ -879,9 +877,14 @@ static float32 addFloat32Sigs(float32 a, float32 b, flag zSign, float_status_t &
else if (expDiff < 0) {
if (bExp == 0xFF) {
if (bSig) return propagateFloat32NaN(a, b, status);
if (aSig && (aExp == 0)) float_raise(status, float_flag_denormal);
return packFloat32(zSign, 0xFF, 0);
}
if ((bExp == 0) && bSig) {
float_raise(status, float_flag_denormal);
}
if (aExp == 0) {
if (aSig) float_raise(status, float_flag_denormal);
++expDiff;
}
else {
@ -895,7 +898,10 @@ static float32 addFloat32Sigs(float32 a, float32 b, flag zSign, float_status_t &
if (aSig | bSig) return propagateFloat32NaN(a, b, status);
return a;
}
if (aExp == 0) return packFloat32(zSign, 0, (aSig + bSig)>>6);
if (aExp == 0) {
if (aSig | bSig) float_raise(status, float_flag_denormal);
return packFloat32(zSign, 0, (aSig + bSig)>>6);
}
zSig = 0x40000000 + aSig + bSig;
zExp = aExp;
goto roundAndPack;
@ -930,13 +936,6 @@ static float32 subFloat32Sigs(float32 a, float32 b, flag zSign, float_status_t &
bSig = extractFloat32Frac(b);
bExp = extractFloat32Exp(b);
if ((aExp == 0) && aSig) {
float_raise(status, float_flag_denormal);
}
if ((bExp == 0) && bSig) {
float_raise(status, float_flag_denormal);
}
expDiff = aExp - bExp;
aSig <<= 7;
bSig <<= 7;
@ -948,6 +947,7 @@ static float32 subFloat32Sigs(float32 a, float32 b, flag zSign, float_status_t &
return float32_default_nan;
}
if (aExp == 0) {
if (aSig | bSig) float_raise(status, float_flag_denormal);
aExp = 1;
bExp = 1;
}
@ -957,9 +957,14 @@ static float32 subFloat32Sigs(float32 a, float32 b, flag zSign, float_status_t &
bExpBigger:
if (bExp == 0xFF) {
if (bSig) return propagateFloat32NaN(a, b, status);
if (aSig && (aExp == 0)) float_raise(status, float_flag_denormal);
return packFloat32(zSign ^ 1, 0xFF, 0);
}
if ((bExp == 0) && bSig) {
float_raise(status, float_flag_denormal);
}
if (aExp == 0) {
if (aSig) float_raise(status, float_flag_denormal);
++expDiff;
}
else {
@ -975,9 +980,14 @@ static float32 subFloat32Sigs(float32 a, float32 b, flag zSign, float_status_t &
aExpBigger:
if (aExp == 0xFF) {
if (aSig) return propagateFloat32NaN(a, b, status);
if (bSig && (bExp == 0)) float_raise(status, float_flag_denormal);
return a;
}
if ((aExp == 0) && aSig) {
float_raise(status, float_flag_denormal);
}
if (bExp == 0) {
if (bSig) float_raise(status, float_flag_denormal);
--expDiff;
}
else {
@ -1857,22 +1867,20 @@ static float64 addFloat64Sigs(float64 a, float64 b, flag zSign, float_status_t &
bSig = extractFloat64Frac(b);
bExp = extractFloat64Exp(b);
if ((aExp == 0) && aSig) {
float_raise(status, float_flag_denormal);
}
if ((bExp == 0) && bSig) {
float_raise(status, float_flag_denormal);
}
expDiff = aExp - bExp;
aSig <<= 9;
bSig <<= 9;
if (0 < expDiff) {
if (aExp == 0x7FF) {
if (aSig) return propagateFloat64NaN(a, b, status);
if (aSig && (aExp == 0)) float_raise(status, float_flag_denormal);
return a;
}
if ((aExp == 0) && aSig) {
float_raise(status, float_flag_denormal);
}
if (bExp == 0) {
if (bSig) float_raise(status, float_flag_denormal);
--expDiff;
}
else {
@ -1884,9 +1892,14 @@ static float64 addFloat64Sigs(float64 a, float64 b, flag zSign, float_status_t &
else if (expDiff < 0) {
if (bExp == 0x7FF) {
if (bSig) return propagateFloat64NaN(a, b, status);
if (bSig && (bExp == 0)) float_raise(status, float_flag_denormal);
return packFloat64(zSign, 0x7FF, 0);
}
if ((bExp == 0) && bSig) {
float_raise(status, float_flag_denormal);
}
if (aExp == 0) {
if (aSig) float_raise(status, float_flag_denormal);
++expDiff;
}
else {
@ -1900,7 +1913,10 @@ static float64 addFloat64Sigs(float64 a, float64 b, flag zSign, float_status_t &
if (aSig | bSig) return propagateFloat64NaN(a, b, status);
return a;
}
if (aExp == 0) return packFloat64(zSign, 0, (aSig + bSig)>>9);
if (aExp == 0) {
if (aSig | bSig) float_raise(status, float_flag_denormal);
return packFloat64(zSign, 0, (aSig + bSig)>>9);
}
zSig = BX_CONST64(0x4000000000000000) + aSig + bSig;
zExp = aExp;
goto roundAndPack;
@ -1935,13 +1951,6 @@ static float64 subFloat64Sigs(float64 a, float64 b, flag zSign, float_status_t &
bSig = extractFloat64Frac(b);
bExp = extractFloat64Exp(b);
if ((aExp == 0) && aSig) {
float_raise(status, float_flag_denormal);
}
if ((bExp == 0) && bSig) {
float_raise(status, float_flag_denormal);
}
expDiff = aExp - bExp;
aSig <<= 10;
bSig <<= 10;
@ -1953,6 +1962,7 @@ static float64 subFloat64Sigs(float64 a, float64 b, flag zSign, float_status_t &
return float64_default_nan;
}
if (aExp == 0) {
if (aSig | bSig) float_raise(status, float_flag_denormal);
aExp = 1;
bExp = 1;
}
@ -1962,9 +1972,14 @@ static float64 subFloat64Sigs(float64 a, float64 b, flag zSign, float_status_t &
bExpBigger:
if (bExp == 0x7FF) {
if (bSig) return propagateFloat64NaN(a, b, status);
if (aSig && (aExp == 0)) float_raise(status, float_flag_denormal);
return packFloat64(zSign ^ 1, 0x7FF, 0);
}
if ((bExp == 0) && bSig) {
float_raise(status, float_flag_denormal);
}
if (aExp == 0) {
if (aSig) float_raise(status, float_flag_denormal);
++expDiff;
}
else {
@ -1980,9 +1995,14 @@ static float64 subFloat64Sigs(float64 a, float64 b, flag zSign, float_status_t &
aExpBigger:
if (aExp == 0x7FF) {
if (aSig) return propagateFloat64NaN(a, b, status);
if (bSig && (bExp == 0)) float_raise(status, float_flag_denormal);
return a;
}
if ((aExp == 0) && aSig) {
float_raise(status, float_flag_denormal);
}
if (bExp == 0) {
if (bSig) float_raise(status, float_flag_denormal);
--expDiff;
}
else {