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softfloat: Revert and reimplement remaining parts of b645bb4885 and 5a6932d51d
Revert the parts of commitsb645bb4885and5a6932d51dwhich are still in the codebase and under a SoftFloat-2b license. Reimplement support for architectures where the most significant bit in the mantissa is 1 for a signaling NaN rather than a quiet NaN, by adding handling for SNAN_BIT_IS_ONE being set to the functions which test values for NaN-ness. This includes restoring the bugfixes lost in the reversion where some of the float*_is_quiet_nan() functions were returning true for both signaling and quiet NaNs. [This is a mechanical squashing together of two separate "revert" and "reimplement" patches.] Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 1421073508-23909-4-git-send-email-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell
parent
6bb8e0f130
commit
332d584970
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@ -33,10 +33,14 @@ this code that are retained.
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===============================================================================
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*/
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/* Does the target distinguish signaling NaNs from non-signaling NaNs
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* by setting the most significant bit of the mantissa for a signaling NaN?
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* (The more common choice is to have it be zero for SNaN and one for QNaN.)
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*/
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#if defined(TARGET_MIPS) || defined(TARGET_SH4) || defined(TARGET_UNICORE32)
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#define SNAN_BIT_IS_ONE 1
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#define SNAN_BIT_IS_ONE 1
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#else
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#define SNAN_BIT_IS_ONE 0
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#define SNAN_BIT_IS_ONE 0
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#endif
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#if defined(TARGET_XTENSA)
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@ -79,7 +83,7 @@ const float64 float64_default_nan = const_float64(LIT64( 0x7FFFFFFFFFFFFFFF ));
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#elif defined(TARGET_PPC) || defined(TARGET_ARM) || defined(TARGET_ALPHA)
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const float64 float64_default_nan = const_float64(LIT64( 0x7FF8000000000000 ));
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#elif SNAN_BIT_IS_ONE
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const float64 float64_default_nan = const_float64(LIT64( 0x7FF7FFFFFFFFFFFF ));
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const float64 float64_default_nan = const_float64(LIT64(0x7FF7FFFFFFFFFFFF));
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#else
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const float64 float64_default_nan = const_float64(LIT64( 0xFFF8000000000000 ));
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#endif
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@ -89,7 +93,7 @@ const float64 float64_default_nan = const_float64(LIT64( 0xFFF8000000000000 ));
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*----------------------------------------------------------------------------*/
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#if SNAN_BIT_IS_ONE
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#define floatx80_default_nan_high 0x7FFF
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#define floatx80_default_nan_low LIT64( 0xBFFFFFFFFFFFFFFF )
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#define floatx80_default_nan_low LIT64(0xBFFFFFFFFFFFFFFF)
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#else
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#define floatx80_default_nan_high 0xFFFF
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#define floatx80_default_nan_low LIT64( 0xC000000000000000 )
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@ -103,8 +107,8 @@ const floatx80 floatx80_default_nan
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| `low' values hold the most- and least-significant bits, respectively.
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*----------------------------------------------------------------------------*/
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#if SNAN_BIT_IS_ONE
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#define float128_default_nan_high LIT64( 0x7FFF7FFFFFFFFFFF )
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#define float128_default_nan_low LIT64( 0xFFFFFFFFFFFFFFFF )
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#define float128_default_nan_high LIT64(0x7FFF7FFFFFFFFFFF)
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#define float128_default_nan_low LIT64(0xFFFFFFFFFFFFFFFF)
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#else
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#define float128_default_nan_high LIT64( 0xFFFF800000000000 )
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#define float128_default_nan_low LIT64( 0x0000000000000000 )
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@ -255,9 +259,9 @@ int float32_is_quiet_nan( float32 a_ )
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{
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uint32_t a = float32_val(a_);
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#if SNAN_BIT_IS_ONE
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return ( ( ( a>>22 ) & 0x1FF ) == 0x1FE ) && ( a & 0x003FFFFF );
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return (((a >> 22) & 0x1ff) == 0x1fe) && (a & 0x003fffff);
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#else
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return ( 0xFF800000 <= (uint32_t) ( a<<1 ) );
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return ((uint32_t)(a << 1) >= 0xff800000);
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#endif
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}
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@ -270,7 +274,7 @@ int float32_is_signaling_nan( float32 a_ )
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{
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uint32_t a = float32_val(a_);
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#if SNAN_BIT_IS_ONE
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return ( 0xFF800000 <= (uint32_t) ( a<<1 ) );
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return ((uint32_t)(a << 1) >= 0xff800000);
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#else
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return ( ( ( a>>22 ) & 0x1FF ) == 0x1FE ) && ( a & 0x003FFFFF );
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#endif
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@ -663,11 +667,10 @@ int float64_is_quiet_nan( float64 a_ )
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{
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uint64_t a = float64_val(a_);
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#if SNAN_BIT_IS_ONE
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return
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( ( ( a>>51 ) & 0xFFF ) == 0xFFE )
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&& ( a & LIT64( 0x0007FFFFFFFFFFFF ) );
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return (((a >> 51) & 0xfff) == 0xffe)
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&& (a & 0x0007ffffffffffffULL);
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#else
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return ( LIT64( 0xFFF0000000000000 ) <= (uint64_t) ( a<<1 ) );
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return ((a << 1) >= 0xfff0000000000000ULL);
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#endif
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}
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@ -680,7 +683,7 @@ int float64_is_signaling_nan( float64 a_ )
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{
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uint64_t a = float64_val(a_);
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#if SNAN_BIT_IS_ONE
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return ( LIT64( 0xFFF0000000000000 ) <= (uint64_t) ( a<<1 ) );
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return ((a << 1) >= 0xfff0000000000000ULL);
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#else
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return
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( ( ( a>>51 ) & 0xFFF ) == 0xFFE )
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@ -864,11 +867,10 @@ int floatx80_is_quiet_nan( floatx80 a )
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#if SNAN_BIT_IS_ONE
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uint64_t aLow;
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aLow = a.low & ~ LIT64( 0x4000000000000000 );
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return
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( ( a.high & 0x7FFF ) == 0x7FFF )
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&& (uint64_t) ( aLow<<1 )
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&& ( a.low == aLow );
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aLow = a.low & ~0x4000000000000000ULL;
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return ((a.high & 0x7fff) == 0x7fff)
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&& (aLow << 1)
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&& (a.low == aLow);
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#else
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return ( ( a.high & 0x7FFF ) == 0x7FFF )
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&& (LIT64( 0x8000000000000000 ) <= ((uint64_t) ( a.low<<1 )));
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@ -884,8 +886,8 @@ int floatx80_is_quiet_nan( floatx80 a )
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int floatx80_is_signaling_nan( floatx80 a )
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{
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#if SNAN_BIT_IS_ONE
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return ( ( a.high & 0x7FFF ) == 0x7FFF )
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&& (LIT64( 0x8000000000000000 ) <= ((uint64_t) ( a.low<<1 )));
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return ((a.high & 0x7fff) == 0x7fff)
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&& ((a.low << 1) >= 0x8000000000000000ULL);
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#else
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uint64_t aLow;
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@ -1029,13 +1031,12 @@ int float128_is_signaling_nan(float128 a_)
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int float128_is_quiet_nan( float128 a )
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{
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#if SNAN_BIT_IS_ONE
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return
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( ( ( a.high>>47 ) & 0xFFFF ) == 0xFFFE )
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&& ( a.low || ( a.high & LIT64( 0x00007FFFFFFFFFFF ) ) );
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return (((a.high >> 47) & 0xffff) == 0xfffe)
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&& (a.low || (a.high & 0x00007fffffffffffULL));
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#else
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return
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( LIT64( 0xFFFE000000000000 ) <= (uint64_t) ( a.high<<1 ) )
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&& ( a.low || ( a.high & LIT64( 0x0000FFFFFFFFFFFF ) ) );
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((a.high << 1) >= 0xffff000000000000ULL)
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&& (a.low || (a.high & 0x0000ffffffffffffULL));
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#endif
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}
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@ -1048,8 +1049,8 @@ int float128_is_signaling_nan( float128 a )
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{
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#if SNAN_BIT_IS_ONE
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return
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( LIT64( 0xFFFE000000000000 ) <= (uint64_t) ( a.high<<1 ) )
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&& ( a.low || ( a.high & LIT64( 0x0000FFFFFFFFFFFF ) ) );
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((a.high << 1) >= 0xffff000000000000ULL)
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&& (a.low || (a.high & 0x0000ffffffffffffULL));
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#else
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return
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( ( ( a.high>>47 ) & 0xFFFF ) == 0xFFFE )
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