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fpu/softfloat: Define floatN_default_nan in terms of parts_default_nan

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Isolate the target-specific choice to 2 functions instead of 6.

The code in float16_default_nan was only correct for ARM, MIPS, and X86.
Though float16 support is rare among our targets.

The code in float128_default_nan was arguably wrong for Sparc.  While
QEMU supports the Sparc 128-bit insns, no real cpu enables it.

The code in floatx80_default_nan tried to be over-general.  There are
only two targets that support this format: x86 and m68k.  Thus there
is no point in inventing a value for snan_bit_is_one.

Move routines that no longer have ifdefs out of softfloat-specialize.h.

Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2018-05-14 13:56:44 -07:00
parent 3bd2dec1a1
commit 0218a16e54
2 changed files with 47 additions and 99 deletions
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41
fpu/softfloat.c
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@ -2092,6 +2092,47 @@ float64 __attribute__((flatten)) float64_sqrt(float64 a, float_status *status)
return float64_round_pack_canonical(pr, status);
}
/*----------------------------------------------------------------------------
| The pattern for a default generated NaN.
*----------------------------------------------------------------------------*/
float16 float16_default_nan(float_status *status)
{
FloatParts p = parts_default_nan(status);
p.frac >>= float16_params.frac_shift;
return float16_pack_raw(p);
}
float32 float32_default_nan(float_status *status)
{
FloatParts p = parts_default_nan(status);
p.frac >>= float32_params.frac_shift;
return float32_pack_raw(p);
}
float64 float64_default_nan(float_status *status)
{
FloatParts p = parts_default_nan(status);
p.frac >>= float64_params.frac_shift;
return float64_pack_raw(p);
}
float128 float128_default_nan(float_status *status)
{
FloatParts p = parts_default_nan(status);
float128 r;
/* Extrapolate from the choices made by parts_default_nan to fill
* in the quad-floating format. If the low bit is set, assume we
* want to set all non-snan bits.
*/
r.low = -(p.frac & 1);
r.high = p.frac >> (DECOMPOSED_BINARY_POINT - 48);
r.high |= LIT64(0x7FFF000000000000);
r.high |= (uint64_t)p.sign << 63;
return r;
}
/*----------------------------------------------------------------------------
| Takes a 64-bit fixed-point value `absZ' with binary point between bits 6