softfloat: Change tininess_before_rounding to bool

Slightly tidies the usage within softfloat.c and the
representation in float_status.

Backports commit a828b373bdabc7e53d1e218e3fc76f85b6674688 from qemu
This commit is contained in:
Richard Henderson 2020-05-21 17:52:47 -04:00 committed by Lioncash
parent a417227674
commit a5c8178e35
3 changed files with 27 additions and 43 deletions

View file

@ -745,8 +745,7 @@ static FloatParts round_canonical(FloatParts p, float_status *s,
p.cls = float_class_zero;
goto do_zero;
} else {
bool is_tiny = (s->float_detect_tininess
== float_tininess_before_rounding)
bool is_tiny = s->tininess_before_rounding
|| (exp < 0)
|| !((frac + inc) & DECOMPOSED_OVERFLOW_BIT);
@ -3540,11 +3539,9 @@ static float32 roundAndPackFloat32(bool zSign, int zExp, uint32_t zSig,
float_raise(float_flag_output_denormal, status);
return packFloat32(zSign, 0, 0);
}
isTiny =
(status->float_detect_tininess
== float_tininess_before_rounding)
|| ( zExp < -1 )
|| ( zSig + roundIncrement < 0x80000000 );
isTiny = status->tininess_before_rounding
|| (zExp < -1)
|| (zSig + roundIncrement < 0x80000000);
shift32RightJamming( zSig, - zExp, &zSig );
zExp = 0;
roundBits = zSig & 0x7F;
@ -3696,11 +3693,9 @@ static float64 roundAndPackFloat64(bool zSign, int zExp, uint64_t zSig,
float_raise(float_flag_output_denormal, status);
return packFloat64(zSign, 0, 0);
}
isTiny =
(status->float_detect_tininess
== float_tininess_before_rounding)
|| ( zExp < -1 )
|| ( zSig + roundIncrement < UINT64_C(0x8000000000000000) );
isTiny = status->tininess_before_rounding
|| (zExp < -1)
|| (zSig + roundIncrement < UINT64_C(0x8000000000000000));
shift64RightJamming( zSig, - zExp, &zSig );
zExp = 0;
roundBits = zSig & 0x3FF;
@ -3839,11 +3834,9 @@ floatx80 roundAndPackFloatx80(int8_t roundingPrecision, bool zSign,
float_raise(float_flag_output_denormal, status);
return packFloatx80(zSign, 0, 0);
}
isTiny =
(status->float_detect_tininess
== float_tininess_before_rounding)
|| ( zExp < 0 )
|| ( zSig0 <= zSig0 + roundIncrement );
isTiny = status->tininess_before_rounding
|| (zExp < 0 )
|| (zSig0 <= zSig0 + roundIncrement);
shift64RightJamming( zSig0, 1 - zExp, &zSig0 );
zExp = 0;
roundBits = zSig0 & roundMask;
@ -3917,12 +3910,10 @@ floatx80 roundAndPackFloatx80(int8_t roundingPrecision, bool zSign,
floatx80_infinity_low);
}
if ( zExp <= 0 ) {
isTiny =
(status->float_detect_tininess
== float_tininess_before_rounding)
|| ( zExp < 0 )
|| ! increment
|| ( zSig0 < UINT64_C(0xFFFFFFFFFFFFFFFF) );
isTiny = status->tininess_before_rounding
|| (zExp < 0)
|| !increment
|| (zSig0 < UINT64_C(0xFFFFFFFFFFFFFFFF));
shift64ExtraRightJamming( zSig0, zSig1, 1 - zExp, &zSig0, &zSig1 );
zExp = 0;
if (isTiny && zSig1) {
@ -4198,17 +4189,12 @@ static float128 roundAndPackFloat128(bool zSign, int32_t zExp,
float_raise(float_flag_output_denormal, status);
return packFloat128(zSign, 0, 0, 0);
}
isTiny =
(status->float_detect_tininess
== float_tininess_before_rounding)
|| ( zExp < -1 )
|| ! increment
|| lt128(
zSig0,
zSig1,
UINT64_C(0x0001FFFFFFFFFFFF),
UINT64_C(0xFFFFFFFFFFFFFFFF)
);
isTiny = status->tininess_before_rounding
|| (zExp < -1)
|| !increment
|| lt128(zSig0, zSig1,
UINT64_C(0x0001FFFFFFFFFFFF),
UINT64_C(0xFFFFFFFFFFFFFFFF));
shift128ExtraRightJamming(
zSig0, zSig1, zSig2, - zExp, &zSig0, &zSig1, &zSig2 );
zExp = 0;

View file

@ -53,9 +53,9 @@ this code that are retained.
#include "fpu/softfloat-types.h"
static inline void set_float_detect_tininess(int val, float_status *status)
static inline void set_float_detect_tininess(bool val, float_status *status)
{
status->float_detect_tininess = val;
status->tininess_before_rounding = val;
}
static inline void set_float_rounding_mode(int val, float_status *status)
@ -94,9 +94,9 @@ static inline void set_snan_bit_is_one(bool val, float_status *status)
status->snan_bit_is_one = val;
}
static inline int get_float_detect_tininess(float_status *status)
static inline bool get_float_detect_tininess(float_status *status)
{
return status->float_detect_tininess;
return status->tininess_before_rounding;
}
static inline int get_float_rounding_mode(float_status *status)

View file

@ -116,10 +116,8 @@ typedef struct {
* Software IEC/IEEE floating-point underflow tininess-detection mode.
*/
enum {
float_tininess_after_rounding = 0,
float_tininess_before_rounding = 1
};
#define float_tininess_after_rounding false
#define float_tininess_before_rounding true
/*
*Software IEC/IEEE floating-point rounding mode.
@ -158,10 +156,10 @@ enum {
*/
typedef struct float_status {
signed char float_detect_tininess;
signed char float_rounding_mode;
uint8_t float_exception_flags;
signed char floatx80_rounding_precision;
bool tininess_before_rounding;
/* should denormalised results go to zero and set the inexact flag? */
bool flush_to_zero;
/* should denormalised inputs go to zero and set the input_denormal flag? */