softfloat: Convert float-to-float conversions with float128

Introduce parts_float_to_float_widen and parts_float_to_float_narrow.
Use them for float128_to_float{32,64} and float{32,64}_to_float128.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2020-11-13 18:17:39 -08:00
parent c3f1875ea3
commit 9882ccaff9

View file

@ -2092,6 +2092,35 @@ static void parts128_float_to_float(FloatParts128 *a, float_status *s)
#define parts_float_to_float(P, S) \
PARTS_GENERIC_64_128(float_to_float, P)(P, S)
static void parts_float_to_float_narrow(FloatParts64 *a, FloatParts128 *b,
float_status *s)
{
a->cls = b->cls;
a->sign = b->sign;
a->exp = b->exp;
if (a->cls == float_class_normal) {
frac_truncjam(a, b);
} else if (is_nan(a->cls)) {
/* Discard the low bits of the NaN. */
a->frac = b->frac_hi;
parts_return_nan(a, s);
}
}
static void parts_float_to_float_widen(FloatParts128 *a, FloatParts64 *b,
float_status *s)
{
a->cls = b->cls;
a->sign = b->sign;
a->exp = b->exp;
frac_widen(a, b);
if (is_nan(a->cls)) {
parts_return_nan(a, s);
}
}
float32 float16_to_float32(float16 a, bool ieee, float_status *s)
{
const FloatFmt *fmt16 = ieee ? &float16_params : &float16_params_ahp;
@ -2215,6 +2244,46 @@ bfloat16 float64_to_bfloat16(float64 a, float_status *s)
return bfloat16_round_pack_canonical(&p, s);
}
float32 float128_to_float32(float128 a, float_status *s)
{
FloatParts64 p64;
FloatParts128 p128;
float128_unpack_canonical(&p128, a, s);
parts_float_to_float_narrow(&p64, &p128, s);
return float32_round_pack_canonical(&p64, s);
}
float64 float128_to_float64(float128 a, float_status *s)
{
FloatParts64 p64;
FloatParts128 p128;
float128_unpack_canonical(&p128, a, s);
parts_float_to_float_narrow(&p64, &p128, s);
return float64_round_pack_canonical(&p64, s);
}
float128 float32_to_float128(float32 a, float_status *s)
{
FloatParts64 p64;
FloatParts128 p128;
float32_unpack_canonical(&p64, a, s);
parts_float_to_float_widen(&p128, &p64, s);
return float128_round_pack_canonical(&p128, s);
}
float128 float64_to_float128(float64 a, float_status *s)
{
FloatParts64 p64;
FloatParts128 p128;
float64_unpack_canonical(&p64, a, s);
parts_float_to_float_widen(&p128, &p64, s);
return float128_round_pack_canonical(&p128, s);
}
/*
* Rounds the floating-point value `a' to an integer, and returns the
* result as a floating-point value. The operation is performed
@ -5175,38 +5244,6 @@ floatx80 float32_to_floatx80(float32 a, float_status *status)
}
/*----------------------------------------------------------------------------
| Returns the result of converting the single-precision floating-point value
| `a' to the double-precision floating-point format. The conversion is
| performed according to the IEC/IEEE Standard for Binary Floating-Point
| Arithmetic.
*----------------------------------------------------------------------------*/
float128 float32_to_float128(float32 a, float_status *status)
{
bool aSign;
int aExp;
uint32_t aSig;
a = float32_squash_input_denormal(a, status);
aSig = extractFloat32Frac( a );
aExp = extractFloat32Exp( a );
aSign = extractFloat32Sign( a );
if ( aExp == 0xFF ) {
if (aSig) {
return commonNaNToFloat128(float32ToCommonNaN(a, status), status);
}
return packFloat128( aSign, 0x7FFF, 0, 0 );
}
if ( aExp == 0 ) {
if ( aSig == 0 ) return packFloat128( aSign, 0, 0, 0 );
normalizeFloat32Subnormal( aSig, &aExp, &aSig );
--aExp;
}
return packFloat128( aSign, aExp + 0x3F80, ( (uint64_t) aSig )<<25, 0 );
}
/*----------------------------------------------------------------------------
| Returns the remainder of the single-precision floating-point value `a'
| with respect to the corresponding value `b'. The operation is performed
@ -5480,40 +5517,6 @@ floatx80 float64_to_floatx80(float64 a, float_status *status)
}
/*----------------------------------------------------------------------------
| Returns the result of converting the double-precision floating-point value
| `a' to the quadruple-precision floating-point format. The conversion is
| performed according to the IEC/IEEE Standard for Binary Floating-Point
| Arithmetic.
*----------------------------------------------------------------------------*/
float128 float64_to_float128(float64 a, float_status *status)
{
bool aSign;
int aExp;
uint64_t aSig, zSig0, zSig1;
a = float64_squash_input_denormal(a, status);
aSig = extractFloat64Frac( a );
aExp = extractFloat64Exp( a );
aSign = extractFloat64Sign( a );
if ( aExp == 0x7FF ) {
if (aSig) {
return commonNaNToFloat128(float64ToCommonNaN(a, status), status);
}
return packFloat128( aSign, 0x7FFF, 0, 0 );
}
if ( aExp == 0 ) {
if ( aSig == 0 ) return packFloat128( aSign, 0, 0, 0 );
normalizeFloat64Subnormal( aSig, &aExp, &aSig );
--aExp;
}
shift128Right( aSig, 0, 4, &zSig0, &zSig1 );
return packFloat128( aSign, aExp + 0x3C00, zSig0, zSig1 );
}
/*----------------------------------------------------------------------------
| Returns the remainder of the double-precision floating-point value `a'
| with respect to the corresponding value `b'. The operation is performed
@ -6915,74 +6918,6 @@ uint32_t float128_to_uint32(float128 a, float_status *status)
return res;
}
/*----------------------------------------------------------------------------
| Returns the result of converting the quadruple-precision floating-point
| value `a' to the single-precision floating-point format. The conversion
| is performed according to the IEC/IEEE Standard for Binary Floating-Point
| Arithmetic.
*----------------------------------------------------------------------------*/
float32 float128_to_float32(float128 a, float_status *status)
{
bool aSign;
int32_t aExp;
uint64_t aSig0, aSig1;
uint32_t zSig;
aSig1 = extractFloat128Frac1( a );
aSig0 = extractFloat128Frac0( a );
aExp = extractFloat128Exp( a );
aSign = extractFloat128Sign( a );
if ( aExp == 0x7FFF ) {
if ( aSig0 | aSig1 ) {
return commonNaNToFloat32(float128ToCommonNaN(a, status), status);
}
return packFloat32( aSign, 0xFF, 0 );
}
aSig0 |= ( aSig1 != 0 );
shift64RightJamming( aSig0, 18, &aSig0 );
zSig = aSig0;
if ( aExp || zSig ) {
zSig |= 0x40000000;
aExp -= 0x3F81;
}
return roundAndPackFloat32(aSign, aExp, zSig, status);
}
/*----------------------------------------------------------------------------
| Returns the result of converting the quadruple-precision floating-point
| value `a' to the double-precision floating-point format. The conversion
| is performed according to the IEC/IEEE Standard for Binary Floating-Point
| Arithmetic.
*----------------------------------------------------------------------------*/
float64 float128_to_float64(float128 a, float_status *status)
{
bool aSign;
int32_t aExp;
uint64_t aSig0, aSig1;
aSig1 = extractFloat128Frac1( a );
aSig0 = extractFloat128Frac0( a );
aExp = extractFloat128Exp( a );
aSign = extractFloat128Sign( a );
if ( aExp == 0x7FFF ) {
if ( aSig0 | aSig1 ) {
return commonNaNToFloat64(float128ToCommonNaN(a, status), status);
}
return packFloat64( aSign, 0x7FF, 0 );
}
shortShift128Left( aSig0, aSig1, 14, &aSig0, &aSig1 );
aSig0 |= ( aSig1 != 0 );
if ( aExp || aSig0 ) {
aSig0 |= UINT64_C(0x4000000000000000);
aExp -= 0x3C01;
}
return roundAndPackFloat64(aSign, aExp, aSig0, status);
}
/*----------------------------------------------------------------------------
| Returns the result of converting the quadruple-precision floating-point
| value `a' to the extended double-precision floating-point format. The