From 74d707e2cc1e406068acad8e5559cd2584b1073a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Alex=20Benn=C3=A9e?= Date: Thu, 7 Dec 2017 18:56:50 +0000 Subject: fpu/softfloat: re-factor mul MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit We can now add float16_mul and use the common decompose and canonicalize functions to have a single implementation for float16/32/64 versions. Signed-off-by: Alex Bennée Signed-off-by: Richard Henderson Reviewed-by: Peter Maydell --- fpu/softfloat.c | 209 ++++++++++++++++++++++---------------------------------- 1 file changed, 81 insertions(+), 128 deletions(-) (limited to 'fpu') diff --git a/fpu/softfloat.c b/fpu/softfloat.c index 2190e7de56..6d29e1a103 100644 --- a/fpu/softfloat.c +++ b/fpu/softfloat.c @@ -735,6 +735,87 @@ float64 __attribute__((flatten)) float64_sub(float64 a, float64 b, return float64_round_pack_canonical(pr, status); } +/* + * Returns the result of multiplying the floating-point values `a' and + * `b'. The operation is performed according to the IEC/IEEE Standard + * for Binary Floating-Point Arithmetic. + */ + +static FloatParts mul_floats(FloatParts a, FloatParts b, float_status *s) +{ + bool sign = a.sign ^ b.sign; + + if (a.cls == float_class_normal && b.cls == float_class_normal) { + uint64_t hi, lo; + int exp = a.exp + b.exp; + + mul64To128(a.frac, b.frac, &hi, &lo); + shift128RightJamming(hi, lo, DECOMPOSED_BINARY_POINT, &hi, &lo); + if (lo & DECOMPOSED_OVERFLOW_BIT) { + shift64RightJamming(lo, 1, &lo); + exp += 1; + } + + /* Re-use a */ + a.exp = exp; + a.sign = sign; + a.frac = lo; + return a; + } + /* handle all the NaN cases */ + if (is_nan(a.cls) || is_nan(b.cls)) { + return pick_nan(a, b, s); + } + /* Inf * Zero == NaN */ + if ((a.cls == float_class_inf && b.cls == float_class_zero) || + (a.cls == float_class_zero && b.cls == float_class_inf)) { + s->float_exception_flags |= float_flag_invalid; + a.cls = float_class_dnan; + a.sign = sign; + return a; + } + /* Multiply by 0 or Inf */ + if (a.cls == float_class_inf || a.cls == float_class_zero) { + a.sign = sign; + return a; + } + if (b.cls == float_class_inf || b.cls == float_class_zero) { + b.sign = sign; + return b; + } + g_assert_not_reached(); +} + +float16 __attribute__((flatten)) float16_mul(float16 a, float16 b, + float_status *status) +{ + FloatParts pa = float16_unpack_canonical(a, status); + FloatParts pb = float16_unpack_canonical(b, status); + FloatParts pr = mul_floats(pa, pb, status); + + return float16_round_pack_canonical(pr, status); +} + +float32 __attribute__((flatten)) float32_mul(float32 a, float32 b, + float_status *status) +{ + FloatParts pa = float32_unpack_canonical(a, status); + FloatParts pb = float32_unpack_canonical(b, status); + FloatParts pr = mul_floats(pa, pb, status); + + return float32_round_pack_canonical(pr, status); +} + +float64 __attribute__((flatten)) float64_mul(float64 a, float64 b, + float_status *status) +{ + FloatParts pa = float64_unpack_canonical(a, status); + FloatParts pb = float64_unpack_canonical(b, status); + FloatParts pr = mul_floats(pa, pb, status); + + return float64_round_pack_canonical(pr, status); +} + /*---------------------------------------------------------------------------- | Takes a 64-bit fixed-point value `absZ' with binary point between bits 6 | and 7, and returns the properly rounded 32-bit integer corresponding to the @@ -2546,70 +2627,6 @@ float32 float32_round_to_int(float32 a, float_status *status) } -/*---------------------------------------------------------------------------- -| Returns the result of multiplying the single-precision floating-point values -| `a' and `b'. The operation is performed according to the IEC/IEEE Standard -| for Binary Floating-Point Arithmetic. -*----------------------------------------------------------------------------*/ - -float32 float32_mul(float32 a, float32 b, float_status *status) -{ - flag aSign, bSign, zSign; - int aExp, bExp, zExp; - uint32_t aSig, bSig; - uint64_t zSig64; - uint32_t zSig; - - a = float32_squash_input_denormal(a, status); - b = float32_squash_input_denormal(b, status); - - aSig = extractFloat32Frac( a ); - aExp = extractFloat32Exp( a ); - aSign = extractFloat32Sign( a ); - bSig = extractFloat32Frac( b ); - bExp = extractFloat32Exp( b ); - bSign = extractFloat32Sign( b ); - zSign = aSign ^ bSign; - if ( aExp == 0xFF ) { - if ( aSig || ( ( bExp == 0xFF ) && bSig ) ) { - return propagateFloat32NaN(a, b, status); - } - if ( ( bExp | bSig ) == 0 ) { - float_raise(float_flag_invalid, status); - return float32_default_nan(status); - } - return packFloat32( zSign, 0xFF, 0 ); - } - if ( bExp == 0xFF ) { - if (bSig) { - return propagateFloat32NaN(a, b, status); - } - if ( ( aExp | aSig ) == 0 ) { - float_raise(float_flag_invalid, status); - return float32_default_nan(status); - } - return packFloat32( zSign, 0xFF, 0 ); - } - if ( aExp == 0 ) { - if ( aSig == 0 ) return packFloat32( zSign, 0, 0 ); - normalizeFloat32Subnormal( aSig, &aExp, &aSig ); - } - if ( bExp == 0 ) { - if ( bSig == 0 ) return packFloat32( zSign, 0, 0 ); - normalizeFloat32Subnormal( bSig, &bExp, &bSig ); - } - zExp = aExp + bExp - 0x7F; - aSig = ( aSig | 0x00800000 )<<7; - bSig = ( bSig | 0x00800000 )<<8; - shift64RightJamming( ( (uint64_t) aSig ) * bSig, 32, &zSig64 ); - zSig = zSig64; - if ( 0 <= (int32_t) ( zSig<<1 ) ) { - zSig <<= 1; - --zExp; - } - return roundAndPackFloat32(zSign, zExp, zSig, status); - -} /*---------------------------------------------------------------------------- | Returns the result of dividing the single-precision floating-point value `a' @@ -4142,70 +4159,6 @@ float64 float64_trunc_to_int(float64 a, float_status *status) return res; } - -/*---------------------------------------------------------------------------- -| Returns the result of multiplying the double-precision floating-point values -| `a' and `b'. The operation is performed according to the IEC/IEEE Standard -| for Binary Floating-Point Arithmetic. -*----------------------------------------------------------------------------*/ - -float64 float64_mul(float64 a, float64 b, float_status *status) -{ - flag aSign, bSign, zSign; - int aExp, bExp, zExp; - uint64_t aSig, bSig, zSig0, zSig1; - - a = float64_squash_input_denormal(a, status); - b = float64_squash_input_denormal(b, status); - - aSig = extractFloat64Frac( a ); - aExp = extractFloat64Exp( a ); - aSign = extractFloat64Sign( a ); - bSig = extractFloat64Frac( b ); - bExp = extractFloat64Exp( b ); - bSign = extractFloat64Sign( b ); - zSign = aSign ^ bSign; - if ( aExp == 0x7FF ) { - if ( aSig || ( ( bExp == 0x7FF ) && bSig ) ) { - return propagateFloat64NaN(a, b, status); - } - if ( ( bExp | bSig ) == 0 ) { - float_raise(float_flag_invalid, status); - return float64_default_nan(status); - } - return packFloat64( zSign, 0x7FF, 0 ); - } - if ( bExp == 0x7FF ) { - if (bSig) { - return propagateFloat64NaN(a, b, status); - } - if ( ( aExp | aSig ) == 0 ) { - float_raise(float_flag_invalid, status); - return float64_default_nan(status); - } - return packFloat64( zSign, 0x7FF, 0 ); - } - if ( aExp == 0 ) { - if ( aSig == 0 ) return packFloat64( zSign, 0, 0 ); - normalizeFloat64Subnormal( aSig, &aExp, &aSig ); - } - if ( bExp == 0 ) { - if ( bSig == 0 ) return packFloat64( zSign, 0, 0 ); - normalizeFloat64Subnormal( bSig, &bExp, &bSig ); - } - zExp = aExp + bExp - 0x3FF; - aSig = ( aSig | LIT64( 0x0010000000000000 ) )<<10; - bSig = ( bSig | LIT64( 0x0010000000000000 ) )<<11; - mul64To128( aSig, bSig, &zSig0, &zSig1 ); - zSig0 |= ( zSig1 != 0 ); - if ( 0 <= (int64_t) ( zSig0<<1 ) ) { - zSig0 <<= 1; - --zExp; - } - return roundAndPackFloat64(zSign, zExp, zSig0, status); - -} - /*---------------------------------------------------------------------------- | Returns the result of dividing the double-precision floating-point value `a' | by the corresponding value `b'. The operation is performed according to -- cgit v1.2.3