?? softfloat.c
字號:
if ( a == 0 ) return 0;
zSign = ( a < 0 );
absA = zSign ? - a : a;
shiftCount = countLeadingZeros32( absA ) + 21;
zSig = absA;
return packFloat64( zSign, 0x432 - shiftCount, zSig<<shiftCount );
}
#ifdef FLOATX80
/*----------------------------------------------------------------------------
| Returns the result of converting the 32-bit two's complement integer `a'
| to the extended double-precision floating-point format. The conversion
| is performed according to the IEC/IEEE Standard for Binary Floating-Point
| Arithmetic.
*----------------------------------------------------------------------------*/
floatx80 int32_to_floatx80( int32 a )
{
flag zSign;
uint32 absA;
int8 shiftCount;
bits64 zSig;
if ( a == 0 ) return packFloatx80( 0, 0, 0 );
zSign = ( a < 0 );
absA = zSign ? - a : a;
shiftCount = countLeadingZeros32( absA ) + 32;
zSig = absA;
return packFloatx80( zSign, 0x403E - shiftCount, zSig<<shiftCount );
}
#endif
#ifdef FLOAT128
/*----------------------------------------------------------------------------
| Returns the result of converting the 32-bit two's complement integer `a' to
| the quadruple-precision floating-point format. The conversion is performed
| according to the IEC/IEEE Standard for Binary Floating-Point Arithmetic.
*----------------------------------------------------------------------------*/
float128 int32_to_float128( int32 a )
{
flag zSign;
uint32 absA;
int8 shiftCount;
bits64 zSig0;
if ( a == 0 ) return packFloat128( 0, 0, 0, 0 );
zSign = ( a < 0 );
absA = zSign ? - a : a;
shiftCount = countLeadingZeros32( absA ) + 17;
zSig0 = absA;
return packFloat128( zSign, 0x402E - shiftCount, zSig0<<shiftCount, 0 );
}
#endif
/*----------------------------------------------------------------------------
| Returns the result of converting the 64-bit two's complement integer `a'
| to the single-precision floating-point format. The conversion is performed
| according to the IEC/IEEE Standard for Binary Floating-Point Arithmetic.
*----------------------------------------------------------------------------*/
float32 int64_to_float32( int64 a )
{
flag zSign;
uint64 absA;
int8 shiftCount;
bits32 zSig;
if ( a == 0 ) return 0;
zSign = ( a < 0 );
absA = zSign ? - a : a;
shiftCount = countLeadingZeros64( absA ) - 40;
if ( 0 <= shiftCount ) {
return packFloat32( zSign, 0x95 - shiftCount, absA<<shiftCount );
}
else {
shiftCount += 7;
if ( shiftCount < 0 ) {
shift64RightJamming( absA, - shiftCount, &absA );
}
else {
absA <<= shiftCount;
}
return roundAndPackFloat32( zSign, 0x9C - shiftCount, absA );
}
}
/*----------------------------------------------------------------------------
| Returns the result of converting the 64-bit two's complement integer `a'
| to the double-precision floating-point format. The conversion is performed
| according to the IEC/IEEE Standard for Binary Floating-Point Arithmetic.
*----------------------------------------------------------------------------*/
float64 int64_to_float64( int64 a )
{
flag zSign;
if ( a == 0 ) return 0;
if ( a == (sbits64) LIT64( 0x8000000000000000 ) ) {
return packFloat64( 1, 0x43E, 0 );
}
zSign = ( a < 0 );
return normalizeRoundAndPackFloat64( zSign, 0x43C, zSign ? - a : a );
}
#ifdef FLOATX80
/*----------------------------------------------------------------------------
| Returns the result of converting the 64-bit two's complement integer `a'
| to the extended double-precision floating-point format. The conversion
| is performed according to the IEC/IEEE Standard for Binary Floating-Point
| Arithmetic.
*----------------------------------------------------------------------------*/
floatx80 int64_to_floatx80( int64 a )
{
flag zSign;
uint64 absA;
int8 shiftCount;
if ( a == 0 ) return packFloatx80( 0, 0, 0 );
zSign = ( a < 0 );
absA = zSign ? - a : a;
shiftCount = countLeadingZeros64( absA );
return packFloatx80( zSign, 0x403E - shiftCount, absA<<shiftCount );
}
#endif
#ifdef FLOAT128
/*----------------------------------------------------------------------------
| Returns the result of converting the 64-bit two's complement integer `a' to
| the quadruple-precision floating-point format. The conversion is performed
| according to the IEC/IEEE Standard for Binary Floating-Point Arithmetic.
*----------------------------------------------------------------------------*/
float128 int64_to_float128( int64 a )
{
flag zSign;
uint64 absA;
int8 shiftCount;
int32 zExp;
bits64 zSig0, zSig1;
if ( a == 0 ) return packFloat128( 0, 0, 0, 0 );
zSign = ( a < 0 );
absA = zSign ? - a : a;
shiftCount = countLeadingZeros64( absA ) + 49;
zExp = 0x406E - shiftCount;
if ( 64 <= shiftCount ) {
zSig1 = 0;
zSig0 = absA;
shiftCount -= 64;
}
else {
zSig1 = absA;
zSig0 = 0;
}
shortShift128Left( zSig0, zSig1, shiftCount, &zSig0, &zSig1 );
return packFloat128( zSign, zExp, zSig0, zSig1 );
}
#endif
/*----------------------------------------------------------------------------
| Returns the result of converting the single-precision floating-point value
| `a' to the 32-bit two's complement integer format. The conversion is
| performed according to the IEC/IEEE Standard for Binary Floating-Point
| Arithmetic---which means in particular that the conversion is rounded
| according to the current rounding mode. If `a' is a NaN, the largest
| positive integer is returned. Otherwise, if the conversion overflows, the
| largest integer with the same sign as `a' is returned.
*----------------------------------------------------------------------------*/
int32 float32_to_int32( float32 a )
{
flag aSign;
int16 aExp, shiftCount;
bits32 aSig;
bits64 aSig64;
aSig = extractFloat32Frac( a );
aExp = extractFloat32Exp( a );
aSign = extractFloat32Sign( a );
if ( ( aExp == 0xFF ) && aSig ) aSign = 0;
if ( aExp ) aSig |= 0x00800000;
shiftCount = 0xAF - aExp;
aSig64 = aSig;
aSig64 <<= 32;
if ( 0 < shiftCount ) shift64RightJamming( aSig64, shiftCount, &aSig64 );
return roundAndPackInt32( aSign, aSig64 );
}
/*----------------------------------------------------------------------------
| Returns the result of converting the single-precision floating-point value
| `a' to the 32-bit two's complement integer format. The conversion is
| performed according to the IEC/IEEE Standard for Binary Floating-Point
| Arithmetic, except that the conversion is always rounded toward zero.
| If `a' is a NaN, the largest positive integer is returned. Otherwise, if
| the conversion overflows, the largest integer with the same sign as `a' is
| returned.
*----------------------------------------------------------------------------*/
int32 float32_to_int32_round_to_zero( float32 a )
{
flag aSign;
int16 aExp, shiftCount;
bits32 aSig;
int32 z;
aSig = extractFloat32Frac( a );
aExp = extractFloat32Exp( a );
aSign = extractFloat32Sign( a );
shiftCount = aExp - 0x9E;
if ( 0 <= shiftCount ) {
if ( a != 0xCF000000 ) {
float_raise( float_flag_invalid );
if ( ! aSign || ( ( aExp == 0xFF ) && aSig ) ) return 0x7FFFFFFF;
}
return (sbits32) 0x80000000;
}
else if ( aExp <= 0x7E ) {
if ( aExp | aSig ) float_exception_flags |= float_flag_inexact;
return 0;
}
aSig = ( aSig | 0x00800000 )<<8;
z = aSig>>( - shiftCount );
if ( (bits32) ( aSig<<( shiftCount & 31 ) ) ) {
float_exception_flags |= float_flag_inexact;
}
if ( aSign ) z = - z;
return z;
}
/*----------------------------------------------------------------------------
| Returns the result of converting the single-precision floating-point value
| `a' to the 64-bit two's complement integer format. The conversion is
| performed according to the IEC/IEEE Standard for Binary Floating-Point
| Arithmetic---which means in particular that the conversion is rounded
| according to the current rounding mode. If `a' is a NaN, the largest
| positive integer is returned. Otherwise, if the conversion overflows, the
| largest integer with the same sign as `a' is returned.
*----------------------------------------------------------------------------*/
int64 float32_to_int64( float32 a )
{
flag aSign;
int16 aExp, shiftCount;
bits32 aSig;
bits64 aSig64, aSigExtra;
aSig = extractFloat32Frac( a );
aExp = extractFloat32Exp( a );
aSign = extractFloat32Sign( a );
shiftCount = 0xBE - aExp;
if ( shiftCount < 0 ) {
float_raise( float_flag_invalid );
if ( ! aSign || ( ( aExp == 0xFF ) && aSig ) ) {
return LIT64( 0x7FFFFFFFFFFFFFFF );
}
return (sbits64) LIT64( 0x8000000000000000 );
}
if ( aExp ) aSig |= 0x00800000;
aSig64 = aSig;
aSig64 <<= 40;
shift64ExtraRightJamming( aSig64, 0, shiftCount, &aSig64, &aSigExtra );
return roundAndPackInt64( aSign, aSig64, aSigExtra );
}
/*----------------------------------------------------------------------------
| Returns the result of converting the single-precision floating-point value
| `a' to the 64-bit two's complement integer format. The conversion is
| performed according to the IEC/IEEE Standard for Binary Floating-Point
| Arithmetic, except that the conversion is always rounded toward zero. If
| `a' is a NaN, the largest positive integer is returned. Otherwise, if the
| conversion overflows, the largest integer with the same sign as `a' is
| returned.
*----------------------------------------------------------------------------*/
int64 float32_to_int64_round_to_zero( float32 a )
{
flag aSign;
int16 aExp, shiftCount;
bits32 aSig;
bits64 aSig64;
int64 z;
aSig = extractFloat32Frac( a );
aExp = extractFloat32Exp( a );
aSign = extractFloat32Sign( a );
shiftCount = aExp - 0xBE;
if ( 0 <= shiftCount ) {
if ( a != 0xDF000000 ) {
float_raise( float_flag_invalid );
if ( ! aSign || ( ( aExp == 0xFF ) && aSig ) ) {
return LIT64( 0x7FFFFFFFFFFFFFFF );
}
}
return (sbits64) LIT64( 0x8000000000000000 );
}
else if ( aExp <= 0x7E ) {
if ( aExp | aSig ) float_exception_flags |= float_flag_inexact;
return 0;
}
aSig64 = aSig | 0x00800000;
aSig64 <<= 40;
z = aSig64>>( - shiftCount );
if ( (bits64) ( aSig64<<( shiftCount & 63 ) ) ) {
float_exception_flags |= float_flag_inexact;
}
if ( aSign ) z = - z;
return z;
}
/*----------------------------------------------------------------------------
| 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.
*----------------------------------------------------------------------------*/
float64 float32_to_float64( float32 a )
{
flag aSign;
int16 aExp;
bits32 aSig;
aSig = extractFloat32Frac( a );
aExp = extractFloat32Exp( a );
aSign = extractFloat32Sign( a );
if ( aExp == 0xFF ) {
if ( aSig ) return commonNaNToFloat64( float32ToCommonNaN( a ) );
return packFloat64( aSign, 0x7FF, 0 );
}
if ( aExp == 0 ) {
if ( aSig == 0 ) return packFloat64( aSign, 0, 0 );
normalizeFloat32Subnormal( aSig, &aExp, &aSig );
--aExp;
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