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| author | Peter Maydell <peter.maydell@linaro.org> | 2011-05-19 14:46:17 +0100 |
|---|---|---|
| committer | Aurelien Jarno <aurelien@aurel32.net> | 2011-05-23 22:39:35 +0200 |
| commit | e6afc87f804abee7d0479be5e8e31c56d885fafb (patch) | |
| tree | 7583efb95a098017efe645d40a81941d1216f671 /fpu | |
| parent | 43fe9bdb0f64237187aeab809bb98e1b46807538 (diff) | |
| download | qemu-e6afc87f804abee7d0479be5e8e31c56d885fafb.tar.gz | |
softfloat: Add new flag for when denormal result is flushed to zero
Add a new float_flag_output_denormal which is set when the result
of a floating point operation would be denormal but is flushed to
zero because we are in flush_to_zero mode. This is necessary because
some architectures signal this condition as an underflow and others
signal it as an inexact result.
Signed-off-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 | 41 | ||||
| -rw-r--r-- | fpu/softfloat.h | 3 |
2 files changed, 36 insertions, 8 deletions
diff --git a/fpu/softfloat.c b/fpu/softfloat.c index baba1dc44b..e3cd8a7296 100644 --- a/fpu/softfloat.c +++ b/fpu/softfloat.c @@ -341,7 +341,10 @@ static float32 roundAndPackFloat32( flag zSign, int16 zExp, uint32_t zSig STATUS return packFloat32( zSign, 0xFF, - ( roundIncrement == 0 )); } if ( zExp < 0 ) { - if ( STATUS(flush_to_zero) ) return packFloat32( zSign, 0, 0 ); + if (STATUS(flush_to_zero)) { + float_raise(float_flag_output_denormal STATUS_VAR); + return packFloat32(zSign, 0, 0); + } isTiny = ( STATUS(float_detect_tininess) == float_tininess_before_rounding ) || ( zExp < -1 ) @@ -520,7 +523,10 @@ static float64 roundAndPackFloat64( flag zSign, int16 zExp, uint64_t zSig STATUS return packFloat64( zSign, 0x7FF, - ( roundIncrement == 0 )); } if ( zExp < 0 ) { - if ( STATUS(flush_to_zero) ) return packFloat64( zSign, 0, 0 ); + if (STATUS(flush_to_zero)) { + float_raise(float_flag_output_denormal STATUS_VAR); + return packFloat64(zSign, 0, 0); + } isTiny = ( STATUS(float_detect_tininess) == float_tininess_before_rounding ) || ( zExp < -1 ) @@ -699,7 +705,10 @@ static floatx80 goto overflow; } if ( zExp <= 0 ) { - if ( STATUS(flush_to_zero) ) return packFloatx80( zSign, 0, 0 ); + if (STATUS(flush_to_zero)) { + float_raise(float_flag_output_denormal STATUS_VAR); + return packFloatx80(zSign, 0, 0); + } isTiny = ( STATUS(float_detect_tininess) == float_tininess_before_rounding ) || ( zExp < 0 ) @@ -1030,7 +1039,10 @@ static float128 return packFloat128( zSign, 0x7FFF, 0, 0 ); } if ( zExp < 0 ) { - if ( STATUS(flush_to_zero) ) return packFloat128( zSign, 0, 0, 0 ); + if (STATUS(flush_to_zero)) { + float_raise(float_flag_output_denormal STATUS_VAR); + return packFloat128(zSign, 0, 0, 0); + } isTiny = ( STATUS(float_detect_tininess) == float_tininess_before_rounding ) || ( zExp < -1 ) @@ -1761,7 +1773,12 @@ static float32 addFloat32Sigs( float32 a, float32 b, flag zSign STATUS_PARAM) return a; } if ( aExp == 0 ) { - if ( STATUS(flush_to_zero) ) return packFloat32( zSign, 0, 0 ); + if (STATUS(flush_to_zero)) { + if (aSig | bSig) { + float_raise(float_flag_output_denormal STATUS_VAR); + } + return packFloat32(zSign, 0, 0); + } return packFloat32( zSign, 0, ( aSig + bSig )>>6 ); } zSig = 0x40000000 + aSig + bSig; @@ -3120,7 +3137,12 @@ static float64 addFloat64Sigs( float64 a, float64 b, flag zSign STATUS_PARAM ) return a; } if ( aExp == 0 ) { - if ( STATUS(flush_to_zero) ) return packFloat64( zSign, 0, 0 ); + if (STATUS(flush_to_zero)) { + if (aSig | bSig) { + float_raise(float_flag_output_denormal STATUS_VAR); + } + return packFloat64(zSign, 0, 0); + } return packFloat64( zSign, 0, ( aSig + bSig )>>9 ); } zSig = LIT64( 0x4000000000000000 ) + aSig + bSig; @@ -5282,7 +5304,12 @@ static float128 addFloat128Sigs( float128 a, float128 b, flag zSign STATUS_PARAM } add128( aSig0, aSig1, bSig0, bSig1, &zSig0, &zSig1 ); if ( aExp == 0 ) { - if ( STATUS(flush_to_zero) ) return packFloat128( zSign, 0, 0, 0 ); + if (STATUS(flush_to_zero)) { + if (zSig0 | zSig1) { + float_raise(float_flag_output_denormal STATUS_VAR); + } + return packFloat128(zSign, 0, 0, 0); + } return packFloat128( zSign, 0, zSig0, zSig1 ); } zSig2 = 0; diff --git a/fpu/softfloat.h b/fpu/softfloat.h index 5eff0858f1..58c9b7b40c 100644 --- a/fpu/softfloat.h +++ b/fpu/softfloat.h @@ -193,7 +193,8 @@ enum { float_flag_overflow = 8, float_flag_underflow = 16, float_flag_inexact = 32, - float_flag_input_denormal = 64 + float_flag_input_denormal = 64, + float_flag_output_denormal = 128 }; typedef struct float_status { |