diff options
Diffstat (limited to 'fpu/softfloat-specialize.h')
| -rw-r--r-- | fpu/softfloat-specialize.h | 374 |
1 files changed, 253 insertions, 121 deletions
diff --git a/fpu/softfloat-specialize.h b/fpu/softfloat-specialize.h index 07468786f9..f293f24356 100644 --- a/fpu/softfloat-specialize.h +++ b/fpu/softfloat-specialize.h @@ -30,7 +30,7 @@ these four paragraphs for those parts of this code that are retained. =============================================================================*/ -#if defined(TARGET_MIPS) || defined(TARGET_HPPA) +#if defined(TARGET_MIPS) #define SNAN_BIT_IS_ONE 1 #else #define SNAN_BIT_IS_ONE 0 @@ -61,10 +61,8 @@ typedef struct { *----------------------------------------------------------------------------*/ #if defined(TARGET_SPARC) #define float32_default_nan make_float32(0x7FFFFFFF) -#elif defined(TARGET_POWERPC) || defined(TARGET_ARM) || defined(TARGET_ALPHA) +#elif defined(TARGET_PPC) || defined(TARGET_ARM) || defined(TARGET_ALPHA) #define float32_default_nan make_float32(0x7FC00000) -#elif defined(TARGET_HPPA) -#define float32_default_nan make_float32(0x7FA00000) #elif SNAN_BIT_IS_ONE #define float32_default_nan make_float32(0x7FBFFFFF) #else @@ -76,7 +74,7 @@ typedef struct { | NaN; otherwise returns 0. *----------------------------------------------------------------------------*/ -int float32_is_nan( float32 a_ ) +int float32_is_quiet_nan( float32 a_ ) { uint32_t a = float32_val(a_); #if SNAN_BIT_IS_ONE @@ -109,13 +107,17 @@ int float32_is_signaling_nan( float32 a_ ) float32 float32_maybe_silence_nan( float32 a_ ) { if (float32_is_signaling_nan(a_)) { - uint32_t a = float32_val(a_); #if SNAN_BIT_IS_ONE - a &= ~(1 << 22); +# if defined(TARGET_MIPS) + return float32_default_nan; +# else +# error Rules for silencing a signaling NaN are target-specific +# endif #else + bits32 a = float32_val(a_); a |= (1 << 22); -#endif return make_float32(a); +#endif } return a_; } @@ -153,6 +155,118 @@ static float32 commonNaNToFloat32( commonNaNT a ) } /*---------------------------------------------------------------------------- +| Select which NaN to propagate for a two-input operation. +| IEEE754 doesn't specify all the details of this, so the +| algorithm is target-specific. +| The routine is passed various bits of information about the +| two NaNs and should return 0 to select NaN a and 1 for NaN b. +| Note that signalling NaNs are always squashed to quiet NaNs +| by the caller, by calling floatXX_maybe_silence_nan() before +| returning them. +| +| aIsLargerSignificand is only valid if both a and b are NaNs +| of some kind, and is true if a has the larger significand, +| or if both a and b have the same significand but a is +| positive but b is negative. It is only needed for the x87 +| tie-break rule. +*----------------------------------------------------------------------------*/ + +#if defined(TARGET_ARM) +static int pickNaN(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN, + flag aIsLargerSignificand) +{ + /* ARM mandated NaN propagation rules: take the first of: + * 1. A if it is signaling + * 2. B if it is signaling + * 3. A (quiet) + * 4. B (quiet) + * A signaling NaN is always quietened before returning it. + */ + if (aIsSNaN) { + return 0; + } else if (bIsSNaN) { + return 1; + } else if (aIsQNaN) { + return 0; + } else { + return 1; + } +} +#elif defined(TARGET_MIPS) +static int pickNaN(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN, + flag aIsLargerSignificand) +{ + /* According to MIPS specifications, if one of the two operands is + * a sNaN, a new qNaN has to be generated. This is done in + * floatXX_maybe_silence_nan(). For qNaN inputs the specifications + * says: "When possible, this QNaN result is one of the operand QNaN + * values." In practice it seems that most implementations choose + * the first operand if both operands are qNaN. In short this gives + * the following rules: + * 1. A if it is signaling + * 2. B if it is signaling + * 3. A (quiet) + * 4. B (quiet) + * A signaling NaN is always silenced before returning it. + */ + if (aIsSNaN) { + return 0; + } else if (bIsSNaN) { + return 1; + } else if (aIsQNaN) { + return 0; + } else { + return 1; + } +} +#elif defined(TARGET_PPC) +static int pickNaN(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN, + flag aIsLargerSignificand) +{ + /* PowerPC propagation rules: + * 1. A if it sNaN or qNaN + * 2. B if it sNaN or qNaN + * A signaling NaN is always silenced before returning it. + */ + if (aIsSNaN || aIsQNaN) { + return 0; + } else { + return 1; + } +} +#else +static int pickNaN(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN, + flag aIsLargerSignificand) +{ + /* This implements x87 NaN propagation rules: + * SNaN + QNaN => return the QNaN + * two SNaNs => return the one with the larger significand, silenced + * two QNaNs => return the one with the larger significand + * SNaN and a non-NaN => return the SNaN, silenced + * QNaN and a non-NaN => return the QNaN + * + * If we get down to comparing significands and they are the same, + * return the NaN with the positive sign bit (if any). + */ + if (aIsSNaN) { + if (bIsSNaN) { + return aIsLargerSignificand ? 0 : 1; + } + return bIsQNaN ? 1 : 0; + } + else if (aIsQNaN) { + if (bIsSNaN || !bIsQNaN) + return 0; + else { + return aIsLargerSignificand ? 0 : 1; + } + } else { + return 1; + } +} +#endif + +/*---------------------------------------------------------------------------- | Takes two single-precision floating-point values `a' and `b', one of which | is a NaN, and returns the appropriate NaN result. If either `a' or `b' is a | signaling NaN, the invalid exception is raised. @@ -160,47 +274,36 @@ static float32 commonNaNToFloat32( commonNaNT a ) static float32 propagateFloat32NaN( float32 a, float32 b STATUS_PARAM) { - flag aIsNaN, aIsSignalingNaN, bIsNaN, bIsSignalingNaN; - bits32 av, bv, res; + flag aIsQuietNaN, aIsSignalingNaN, bIsQuietNaN, bIsSignalingNaN; + flag aIsLargerSignificand; + bits32 av, bv; if ( STATUS(default_nan_mode) ) return float32_default_nan; - aIsNaN = float32_is_nan( a ); + aIsQuietNaN = float32_is_quiet_nan( a ); aIsSignalingNaN = float32_is_signaling_nan( a ); - bIsNaN = float32_is_nan( b ); + bIsQuietNaN = float32_is_quiet_nan( b ); bIsSignalingNaN = float32_is_signaling_nan( b ); av = float32_val(a); bv = float32_val(b); -#if SNAN_BIT_IS_ONE - av &= ~0x00400000; - bv &= ~0x00400000; -#else - av |= 0x00400000; - bv |= 0x00400000; -#endif + if ( aIsSignalingNaN | bIsSignalingNaN ) float_raise( float_flag_invalid STATUS_VAR); - if ( aIsSignalingNaN ) { - if ( bIsSignalingNaN ) goto returnLargerSignificand; - res = bIsNaN ? bv : av; - } - else if ( aIsNaN ) { - if ( bIsSignalingNaN || ! bIsNaN ) - res = av; - else { - returnLargerSignificand: - if ( (bits32) ( av<<1 ) < (bits32) ( bv<<1 ) ) - res = bv; - else if ( (bits32) ( bv<<1 ) < (bits32) ( av<<1 ) ) - res = av; - else - res = ( av < bv ) ? av : bv; - } + + if ((bits32)(av<<1) < (bits32)(bv<<1)) { + aIsLargerSignificand = 0; + } else if ((bits32)(bv<<1) < (bits32)(av<<1)) { + aIsLargerSignificand = 1; + } else { + aIsLargerSignificand = (av < bv) ? 1 : 0; } - else { - res = bv; + + if (pickNaN(aIsQuietNaN, aIsSignalingNaN, bIsQuietNaN, bIsSignalingNaN, + aIsLargerSignificand)) { + return float32_maybe_silence_nan(b); + } else { + return float32_maybe_silence_nan(a); } - return make_float32(res); } /*---------------------------------------------------------------------------- @@ -208,10 +311,8 @@ static float32 propagateFloat32NaN( float32 a, float32 b STATUS_PARAM) *----------------------------------------------------------------------------*/ #if defined(TARGET_SPARC) #define float64_default_nan make_float64(LIT64( 0x7FFFFFFFFFFFFFFF )) -#elif defined(TARGET_POWERPC) || defined(TARGET_ARM) || defined(TARGET_ALPHA) +#elif defined(TARGET_PPC) || defined(TARGET_ARM) || defined(TARGET_ALPHA) #define float64_default_nan make_float64(LIT64( 0x7FF8000000000000 )) -#elif defined(TARGET_HPPA) -#define float64_default_nan make_float64(LIT64( 0x7FF4000000000000 )) #elif SNAN_BIT_IS_ONE #define float64_default_nan make_float64(LIT64( 0x7FF7FFFFFFFFFFFF )) #else @@ -223,7 +324,7 @@ static float32 propagateFloat32NaN( float32 a, float32 b STATUS_PARAM) | NaN; otherwise returns 0. *----------------------------------------------------------------------------*/ -int float64_is_nan( float64 a_ ) +int float64_is_quiet_nan( float64 a_ ) { bits64 a = float64_val(a_); #if SNAN_BIT_IS_ONE @@ -260,13 +361,17 @@ int float64_is_signaling_nan( float64 a_ ) float64 float64_maybe_silence_nan( float64 a_ ) { if (float64_is_signaling_nan(a_)) { - bits64 a = float64_val(a_); #if SNAN_BIT_IS_ONE - a &= ~LIT64( 0x0008000000000000 ); +# if defined(TARGET_MIPS) + return float64_default_nan; +# else +# error Rules for silencing a signaling NaN are target-specific +# endif #else + bits64 a = float64_val(a_); a |= LIT64( 0x0008000000000000 ); -#endif return make_float64(a); +#endif } return a_; } @@ -314,47 +419,36 @@ static float64 commonNaNToFloat64( commonNaNT a ) static float64 propagateFloat64NaN( float64 a, float64 b STATUS_PARAM) { - flag aIsNaN, aIsSignalingNaN, bIsNaN, bIsSignalingNaN; - bits64 av, bv, res; + flag aIsQuietNaN, aIsSignalingNaN, bIsQuietNaN, bIsSignalingNaN; + flag aIsLargerSignificand; + bits64 av, bv; if ( STATUS(default_nan_mode) ) return float64_default_nan; - aIsNaN = float64_is_nan( a ); + aIsQuietNaN = float64_is_quiet_nan( a ); aIsSignalingNaN = float64_is_signaling_nan( a ); - bIsNaN = float64_is_nan( b ); + bIsQuietNaN = float64_is_quiet_nan( b ); bIsSignalingNaN = float64_is_signaling_nan( b ); av = float64_val(a); bv = float64_val(b); -#if SNAN_BIT_IS_ONE - av &= ~LIT64( 0x0008000000000000 ); - bv &= ~LIT64( 0x0008000000000000 ); -#else - av |= LIT64( 0x0008000000000000 ); - bv |= LIT64( 0x0008000000000000 ); -#endif + if ( aIsSignalingNaN | bIsSignalingNaN ) float_raise( float_flag_invalid STATUS_VAR); - if ( aIsSignalingNaN ) { - if ( bIsSignalingNaN ) goto returnLargerSignificand; - res = bIsNaN ? bv : av; - } - else if ( aIsNaN ) { - if ( bIsSignalingNaN || ! bIsNaN ) - res = av; - else { - returnLargerSignificand: - if ( (bits64) ( av<<1 ) < (bits64) ( bv<<1 ) ) - res = bv; - else if ( (bits64) ( bv<<1 ) < (bits64) ( av<<1 ) ) - res = av; - else - res = ( av < bv ) ? av : bv; - } + + if ((bits64)(av<<1) < (bits64)(bv<<1)) { + aIsLargerSignificand = 0; + } else if ((bits64)(bv<<1) < (bits64)(av<<1)) { + aIsLargerSignificand = 1; + } else { + aIsLargerSignificand = (av < bv) ? 1 : 0; } - else { - res = bv; + + if (pickNaN(aIsQuietNaN, aIsSignalingNaN, bIsQuietNaN, bIsSignalingNaN, + aIsLargerSignificand)) { + return float64_maybe_silence_nan(b); + } else { + return float64_maybe_silence_nan(a); } - return make_float64(res); } #ifdef FLOATX80 @@ -377,7 +471,7 @@ static float64 propagateFloat64NaN( float64 a, float64 b STATUS_PARAM) | quiet NaN; otherwise returns 0. *----------------------------------------------------------------------------*/ -int floatx80_is_nan( floatx80 a ) +int floatx80_is_quiet_nan( floatx80 a ) { #if SNAN_BIT_IS_ONE bits64 aLow; @@ -413,6 +507,29 @@ int floatx80_is_signaling_nan( floatx80 a ) } /*---------------------------------------------------------------------------- +| Returns a quiet NaN if the extended double-precision floating point value +| `a' is a signaling NaN; otherwise returns `a'. +*----------------------------------------------------------------------------*/ + +floatx80 floatx80_maybe_silence_nan( floatx80 a ) +{ + if (floatx80_is_signaling_nan(a)) { +#if SNAN_BIT_IS_ONE +# if defined(TARGET_MIPS) + a.low = floatx80_default_nan_low; + a.high = floatx80_default_nan_high; +# else +# error Rules for silencing a signaling NaN are target-specific +# endif +#else + a.low |= LIT64( 0xC000000000000000 ); + return a; +#endif + } + return a; +} + +/*---------------------------------------------------------------------------- | Returns the result of converting the extended double-precision floating- | point NaN `a' to the canonical NaN format. If `a' is a signaling NaN, the | invalid exception is raised. @@ -454,7 +571,8 @@ static floatx80 commonNaNToFloatx80( commonNaNT a ) static floatx80 propagateFloatx80NaN( floatx80 a, floatx80 b STATUS_PARAM) { - flag aIsNaN, aIsSignalingNaN, bIsNaN, bIsSignalingNaN; + flag aIsQuietNaN, aIsSignalingNaN, bIsQuietNaN, bIsSignalingNaN; + flag aIsLargerSignificand; if ( STATUS(default_nan_mode) ) { a.low = floatx80_default_nan_low; @@ -462,31 +580,26 @@ static floatx80 propagateFloatx80NaN( floatx80 a, floatx80 b STATUS_PARAM) return a; } - aIsNaN = floatx80_is_nan( a ); + aIsQuietNaN = floatx80_is_quiet_nan( a ); aIsSignalingNaN = floatx80_is_signaling_nan( a ); - bIsNaN = floatx80_is_nan( b ); + bIsQuietNaN = floatx80_is_quiet_nan( b ); bIsSignalingNaN = floatx80_is_signaling_nan( b ); -#if SNAN_BIT_IS_ONE - a.low &= ~LIT64( 0xC000000000000000 ); - b.low &= ~LIT64( 0xC000000000000000 ); -#else - a.low |= LIT64( 0xC000000000000000 ); - b.low |= LIT64( 0xC000000000000000 ); -#endif + if ( aIsSignalingNaN | bIsSignalingNaN ) float_raise( float_flag_invalid STATUS_VAR); - if ( aIsSignalingNaN ) { - if ( bIsSignalingNaN ) goto returnLargerSignificand; - return bIsNaN ? b : a; - } - else if ( aIsNaN ) { - if ( bIsSignalingNaN || ! bIsNaN ) return a; - returnLargerSignificand: - if ( a.low < b.low ) return b; - if ( b.low < a.low ) return a; - return ( a.high < b.high ) ? a : b; + + if (a.low < b.low) { + aIsLargerSignificand = 0; + } else if (b.low < a.low) { + aIsLargerSignificand = 1; + } else { + aIsLargerSignificand = (a.high < b.high) ? 1 : 0; } - else { - return b; + + if (pickNaN(aIsQuietNaN, aIsSignalingNaN, bIsQuietNaN, bIsSignalingNaN, + aIsLargerSignificand)) { + return floatx80_maybe_silence_nan(b); + } else { + return floatx80_maybe_silence_nan(a); } } @@ -511,7 +624,7 @@ static floatx80 propagateFloatx80NaN( floatx80 a, floatx80 b STATUS_PARAM) | NaN; otherwise returns 0. *----------------------------------------------------------------------------*/ -int float128_is_nan( float128 a ) +int float128_is_quiet_nan( float128 a ) { #if SNAN_BIT_IS_ONE return @@ -543,6 +656,29 @@ int float128_is_signaling_nan( float128 a ) } /*---------------------------------------------------------------------------- +| Returns a quiet NaN if the quadruple-precision floating point value `a' is +| a signaling NaN; otherwise returns `a'. +*----------------------------------------------------------------------------*/ + +float128 float128_maybe_silence_nan( float128 a ) +{ + if (float128_is_signaling_nan(a)) { +#if SNAN_BIT_IS_ONE +# if defined(TARGET_MIPS) + a.low = float128_default_nan_low; + a.high = float128_default_nan_high; +# else +# error Rules for silencing a signaling NaN are target-specific +# endif +#else + a.high |= LIT64( 0x0000800000000000 ); + return a; +#endif + } + return a; +} + +/*---------------------------------------------------------------------------- | Returns the result of converting the quadruple-precision floating-point NaN | `a' to the canonical NaN format. If `a' is a signaling NaN, the invalid | exception is raised. @@ -580,7 +716,8 @@ static float128 commonNaNToFloat128( commonNaNT a ) static float128 propagateFloat128NaN( float128 a, float128 b STATUS_PARAM) { - flag aIsNaN, aIsSignalingNaN, bIsNaN, bIsSignalingNaN; + flag aIsQuietNaN, aIsSignalingNaN, bIsQuietNaN, bIsSignalingNaN; + flag aIsLargerSignificand; if ( STATUS(default_nan_mode) ) { a.low = float128_default_nan_low; @@ -588,31 +725,26 @@ static float128 propagateFloat128NaN( float128 a, float128 b STATUS_PARAM) return a; } - aIsNaN = float128_is_nan( a ); + aIsQuietNaN = float128_is_quiet_nan( a ); aIsSignalingNaN = float128_is_signaling_nan( a ); - bIsNaN = float128_is_nan( b ); + bIsQuietNaN = float128_is_quiet_nan( b ); bIsSignalingNaN = float128_is_signaling_nan( b ); -#if SNAN_BIT_IS_ONE - a.high &= ~LIT64( 0x0000800000000000 ); - b.high &= ~LIT64( 0x0000800000000000 ); -#else - a.high |= LIT64( 0x0000800000000000 ); - b.high |= LIT64( 0x0000800000000000 ); -#endif + if ( aIsSignalingNaN | bIsSignalingNaN ) float_raise( float_flag_invalid STATUS_VAR); - if ( aIsSignalingNaN ) { - if ( bIsSignalingNaN ) goto returnLargerSignificand; - return bIsNaN ? b : a; - } - else if ( aIsNaN ) { - if ( bIsSignalingNaN || ! bIsNaN ) return a; - returnLargerSignificand: - if ( lt128( a.high<<1, a.low, b.high<<1, b.low ) ) return b; - if ( lt128( b.high<<1, b.low, a.high<<1, a.low ) ) return a; - return ( a.high < b.high ) ? a : b; + + if (lt128(a.high<<1, a.low, b.high<<1, b.low)) { + aIsLargerSignificand = 0; + } else if (lt128(b.high<<1, b.low, a.high<<1, a.low)) { + aIsLargerSignificand = 1; + } else { + aIsLargerSignificand = (a.high < b.high) ? 1 : 0; } - else { - return b; + + if (pickNaN(aIsQuietNaN, aIsSignalingNaN, bIsQuietNaN, bIsSignalingNaN, + aIsLargerSignificand)) { + return float128_maybe_silence_nan(b); + } else { + return float128_maybe_silence_nan(a); } } |