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author | Aurelien Jarno <aurelien@aurel32.net> | 2011-04-20 13:04:22 +0200 |
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committer | Aurelien Jarno <aurelien@aurel32.net> | 2011-04-25 11:18:33 +0200 |
commit | 326b9e98a391d542cc33c4c91782ff4ba51edfc5 (patch) | |
tree | b9cde2b1dea8db271bf7a0875aadf11bc1dcc75d /fpu | |
parent | f6714d365da068481d83787b4044134ae2ec5dfd (diff) | |
download | hqemu-326b9e98a391d542cc33c4c91782ff4ba51edfc5.zip hqemu-326b9e98a391d542cc33c4c91782ff4ba51edfc5.tar.gz |
softfloat: fix float*_scalnb() corner cases
float*_scalnb() were not taking into account all cases. This patch fixes
some corner cases:
- NaN values in input were not properly propagated and the invalid flag
not correctly raised. Use propagateFloat*NaN() for that.
- NaN or infinite values in input of floatx80_scalnb() were not correctly
detected due to a typo.
- The sum of exponent and n could overflow, leading to strange results.
Additionally having int16 defined to int make that happening for a very
small range of values. Fix that by saturating n to the maximum exponent
range, and using an explicit wider type if needed.
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Diffstat (limited to 'fpu')
-rw-r--r-- | fpu/softfloat.c | 47 |
1 files changed, 42 insertions, 5 deletions
diff --git a/fpu/softfloat.c b/fpu/softfloat.c index 4368069..baba1dc 100644 --- a/fpu/softfloat.c +++ b/fpu/softfloat.c @@ -6333,7 +6333,7 @@ MINMAX(64, 0x7ff) float32 float32_scalbn( float32 a, int n STATUS_PARAM ) { flag aSign; - int16 aExp; + int16_t aExp; uint32_t aSig; a = float32_squash_input_denormal(a STATUS_VAR); @@ -6342,6 +6342,9 @@ float32 float32_scalbn( float32 a, int n STATUS_PARAM ) aSign = extractFloat32Sign( a ); if ( aExp == 0xFF ) { + if ( aSig ) { + return propagateFloat32NaN( a, a STATUS_VAR ); + } return a; } if ( aExp != 0 ) @@ -6349,6 +6352,12 @@ float32 float32_scalbn( float32 a, int n STATUS_PARAM ) else if ( aSig == 0 ) return a; + if (n > 0x200) { + n = 0x200; + } else if (n < -0x200) { + n = -0x200; + } + aExp += n - 1; aSig <<= 7; return normalizeRoundAndPackFloat32( aSign, aExp, aSig STATUS_VAR ); @@ -6357,7 +6366,7 @@ float32 float32_scalbn( float32 a, int n STATUS_PARAM ) float64 float64_scalbn( float64 a, int n STATUS_PARAM ) { flag aSign; - int16 aExp; + int16_t aExp; uint64_t aSig; a = float64_squash_input_denormal(a STATUS_VAR); @@ -6366,6 +6375,9 @@ float64 float64_scalbn( float64 a, int n STATUS_PARAM ) aSign = extractFloat64Sign( a ); if ( aExp == 0x7FF ) { + if ( aSig ) { + return propagateFloat64NaN( a, a STATUS_VAR ); + } return a; } if ( aExp != 0 ) @@ -6373,6 +6385,12 @@ float64 float64_scalbn( float64 a, int n STATUS_PARAM ) else if ( aSig == 0 ) return a; + if (n > 0x1000) { + n = 0x1000; + } else if (n < -0x1000) { + n = -0x1000; + } + aExp += n - 1; aSig <<= 10; return normalizeRoundAndPackFloat64( aSign, aExp, aSig STATUS_VAR ); @@ -6382,19 +6400,29 @@ float64 float64_scalbn( float64 a, int n STATUS_PARAM ) floatx80 floatx80_scalbn( floatx80 a, int n STATUS_PARAM ) { flag aSign; - int16 aExp; + int32_t aExp; uint64_t aSig; aSig = extractFloatx80Frac( a ); aExp = extractFloatx80Exp( a ); aSign = extractFloatx80Sign( a ); - if ( aExp == 0x7FF ) { + if ( aExp == 0x7FFF ) { + if ( aSig<<1 ) { + return propagateFloatx80NaN( a, a STATUS_VAR ); + } return a; } + if (aExp == 0 && aSig == 0) return a; + if (n > 0x10000) { + n = 0x10000; + } else if (n < -0x10000) { + n = -0x10000; + } + aExp += n; return normalizeRoundAndPackFloatx80( STATUS(floatx80_rounding_precision), aSign, aExp, aSig, 0 STATUS_VAR ); @@ -6405,7 +6433,7 @@ floatx80 floatx80_scalbn( floatx80 a, int n STATUS_PARAM ) float128 float128_scalbn( float128 a, int n STATUS_PARAM ) { flag aSign; - int32 aExp; + int32_t aExp; uint64_t aSig0, aSig1; aSig1 = extractFloat128Frac1( a ); @@ -6413,6 +6441,9 @@ float128 float128_scalbn( float128 a, int n STATUS_PARAM ) aExp = extractFloat128Exp( a ); aSign = extractFloat128Sign( a ); if ( aExp == 0x7FFF ) { + if ( aSig0 | aSig1 ) { + return propagateFloat128NaN( a, a STATUS_VAR ); + } return a; } if ( aExp != 0 ) @@ -6420,6 +6451,12 @@ float128 float128_scalbn( float128 a, int n STATUS_PARAM ) else if ( aSig0 == 0 && aSig1 == 0 ) return a; + if (n > 0x10000) { + n = 0x10000; + } else if (n < -0x10000) { + n = -0x10000; + } + aExp += n - 1; return normalizeRoundAndPackFloat128( aSign, aExp, aSig0, aSig1 STATUS_VAR ); |