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authorAurelien Jarno <aurelien@aurel32.net>2011-04-20 13:04:22 +0200
committerAurelien Jarno <aurelien@aurel32.net>2011-04-25 11:18:33 +0200
commit326b9e98a391d542cc33c4c91782ff4ba51edfc5 (patch)
treeb9cde2b1dea8db271bf7a0875aadf11bc1dcc75d /fpu/softfloat.c
parentf6714d365da068481d83787b4044134ae2ec5dfd (diff)
downloadqemu-arm-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/softfloat.c')
-rw-r--r--fpu/softfloat.c47
1 files changed, 42 insertions, 5 deletions
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 4368069dd6..baba1dc44b 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 );