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softfloat: Add float128_to_uint64_round_to_zero()

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Implement float128_to_uint64() and use that to implement
float128_to_uint64_round_to_zero()

This is required by xscvqpudz instruction of PowerPC ISA 3.0.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
This commit is contained in:
Bharata B Rao 2017-02-10 12:53:06 +05:30 committed by David Gibson
parent 9ee6f678f4
commit 2e6d856835
2 changed files with 61 additions and 0 deletions
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59
fpu/softfloat.c
View File

@ -6127,6 +6127,65 @@ int64_t float128_to_int64_round_to_zero(float128 a, float_status *status)
} }
/*----------------------------------------------------------------------------
| Returns the result of converting the quadruple-precision floating-point value
| `a' to the 64-bit unsigned 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. If the conversion overflows, the
| largest unsigned integer is returned. If 'a' is negative, the value is
| rounded and zero is returned; negative values that do not round to zero
| will raise the inexact exception.
*----------------------------------------------------------------------------*/
uint64_t float128_to_uint64(float128 a, float_status *status)
{
flag aSign;
int aExp;
int shiftCount;
uint64_t aSig0, aSig1;
aSig0 = extractFloat128Frac0(a);
aSig1 = extractFloat128Frac1(a);
aExp = extractFloat128Exp(a);
aSign = extractFloat128Sign(a);
if (aSign && (aExp > 0x3FFE)) {
float_raise(float_flag_invalid, status);
if (float128_is_any_nan(a)) {
return LIT64(0xFFFFFFFFFFFFFFFF);
} else {
return 0;
}
}
if (aExp) {
aSig0 |= LIT64(0x0001000000000000);
}
shiftCount = 0x402F - aExp;
if (shiftCount <= 0) {
if (0x403E < aExp) {
float_raise(float_flag_invalid, status);
return LIT64(0xFFFFFFFFFFFFFFFF);
}
shortShift128Left(aSig0, aSig1, -shiftCount, &aSig0, &aSig1);
} else {
shift64ExtraRightJamming(aSig0, aSig1, shiftCount, &aSig0, &aSig1);
}
return roundAndPackUint64(aSign, aSig0, aSig1, status);
}
uint64_t float128_to_uint64_round_to_zero(float128 a, float_status *status)
{
uint64_t v;
signed char current_rounding_mode = status->float_rounding_mode;
set_float_rounding_mode(float_round_to_zero, status);
v = float128_to_uint64(a, status);
set_float_rounding_mode(current_rounding_mode, status);
return v;
}
/*---------------------------------------------------------------------------- /*----------------------------------------------------------------------------
| Returns the result of converting the quadruple-precision floating-point | Returns the result of converting the quadruple-precision floating-point
| value `a' to the single-precision floating-point format. The conversion | value `a' to the single-precision floating-point format. The conversion

2
include/fpu/softfloat.h
View File

@ -714,6 +714,8 @@ int32_t float128_to_int32(float128, float_status *status);
int32_t float128_to_int32_round_to_zero(float128, float_status *status); int32_t float128_to_int32_round_to_zero(float128, float_status *status);
int64_t float128_to_int64(float128, float_status *status); int64_t float128_to_int64(float128, float_status *status);
int64_t float128_to_int64_round_to_zero(float128, float_status *status); int64_t float128_to_int64_round_to_zero(float128, float_status *status);
uint64_t float128_to_uint64(float128, float_status *status);
uint64_t float128_to_uint64_round_to_zero(float128, float_status *status);
float32 float128_to_float32(float128, float_status *status); float32 float128_to_float32(float128, float_status *status);
float64 float128_to_float64(float128, float_status *status); float64 float128_to_float64(float128, float_status *status);
floatx80 float128_to_floatx80(float128, float_status *status); floatx80 float128_to_floatx80(float128, float_status *status);