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fpu/softfloat: Pass FloatClass to pickNaN

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For each operand, pass a single enumeration instead of a pair of booleans.
The commit also merges multiple different ifdef-selected implementations
of pickNaN into a single function whose body is ifdef-selected.

Tested-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2018-05-10 15:21:31 -07:00
parent 247d1f2190
commit 4f251cfd52
2 changed files with 82 additions and 89 deletions
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168
fpu/softfloat-specialize.h
View file

@ -501,10 +501,10 @@ static float32 commonNaNToFloat32(commonNaNT a, float_status *status)
| tie-break rule.
*----------------------------------------------------------------------------*/
#if defined(TARGET_ARM)
static int pickNaN(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN,
static int pickNaN(FloatClass a_cls, FloatClass b_cls,
flag aIsLargerSignificand)
{
#if defined(TARGET_ARM) || defined(TARGET_MIPS) || defined(TARGET_HPPA)
/* ARM mandated NaN propagation rules (see FPProcessNaNs()), take
* the first of:
* 1. A if it is signaling
@ -513,20 +513,6 @@ static int pickNaN(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN,
* 4. B (quiet)
* A signaling NaN is always quietened before returning it.
*/
if (aIsSNaN) {
return 0;
} else if (bIsSNaN) {
return 1;
} else if (aIsQNaN) {
return 0;
} else {
return 1;
}
}
#elif defined(TARGET_MIPS) || defined(TARGET_HPPA)
static int pickNaN(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN,
flag aIsLargerSignificand)
{
/* According to MIPS specifications, if one of the two operands is
* a sNaN, a new qNaN has to be generated. This is done in
* floatXX_silence_nan(). For qNaN inputs the specifications
@ -540,35 +526,21 @@ static int pickNaN(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN,
* 4. B (quiet)
* A signaling NaN is always silenced before returning it.
*/
if (aIsSNaN) {
if (is_snan(a_cls)) {
return 0;
} else if (bIsSNaN) {
} else if (is_snan(b_cls)) {
return 1;
} else if (aIsQNaN) {
} else if (is_qnan(a_cls)) {
return 0;
} else {
return 1;
}
}
#elif defined(TARGET_PPC) || defined(TARGET_XTENSA)
static int pickNaN(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN,
flag aIsLargerSignificand)
{
#elif defined(TARGET_PPC) || defined(TARGET_XTENSA) || defined(TARGET_M68K)
/* PowerPC propagation rules:
* 1. A if it sNaN or qNaN
* 2. B if it sNaN or qNaN
* A signaling NaN is always silenced before returning it.
*/
if (aIsSNaN || aIsQNaN) {
return 0;
} else {
return 1;
}
}
#elif defined(TARGET_M68K)
static int pickNaN(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN,
flag aIsLargerSignificand)
{
/* M68000 FAMILY PROGRAMMER'S REFERENCE MANUAL
* 3.4 FLOATING-POINT INSTRUCTION DETAILS
* If either operand, but not both operands, of an operation is a
@ -583,16 +555,12 @@ static int pickNaN(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN,
* a nonsignaling NaN. The operation then continues as described in the
* preceding paragraph for nonsignaling NaNs.
*/
if (aIsQNaN || aIsSNaN) { /* a is the destination operand */
return 0; /* return the destination operand */
if (is_nan(a_cls)) {
return 0;
} else {
return 1; /* return b */
return 1;
}
}
#else
static int pickNaN(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN,
flag aIsLargerSignificand)
{
/* This implements x87 NaN propagation rules:
* SNaN + QNaN => return the QNaN
* two SNaNs => return the one with the larger significand, silenced
@ -603,13 +571,13 @@ static int pickNaN(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN,
* If we get down to comparing significands and they are the same,
* return the NaN with the positive sign bit (if any).
*/
if (aIsSNaN) {
if (bIsSNaN) {
if (is_snan(a_cls)) {
if (is_snan(b_cls)) {
return aIsLargerSignificand ? 0 : 1;
}
return bIsQNaN ? 1 : 0;
} else if (aIsQNaN) {
if (bIsSNaN || !bIsQNaN) {
return is_qnan(b_cls) ? 1 : 0;
} else if (is_qnan(a_cls)) {
if (is_snan(b_cls) || !is_qnan(b_cls)) {
return 0;
} else {
return aIsLargerSignificand ? 0 : 1;
@ -617,8 +585,8 @@ static int pickNaN(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN,
} else {
return 1;
}
}
#endif
}
/*----------------------------------------------------------------------------
| Select which NaN to propagate for a three-input operation.
@ -752,18 +720,26 @@ static int pickNaNMulAdd(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN,
static float32 propagateFloat32NaN(float32 a, float32 b, float_status *status)
{
flag aIsQuietNaN, aIsSignalingNaN, bIsQuietNaN, bIsSignalingNaN;
flag aIsLargerSignificand;
uint32_t av, bv;
FloatClass a_cls, b_cls;
/* This is not complete, but is good enough for pickNaN. */
a_cls = (!float32_is_any_nan(a)
? float_class_normal
: float32_is_signaling_nan(a, status)
? float_class_snan
: float_class_qnan);
b_cls = (!float32_is_any_nan(b)
? float_class_normal
: float32_is_signaling_nan(b, status)
? float_class_snan
: float_class_qnan);
aIsQuietNaN = float32_is_quiet_nan(a, status);
aIsSignalingNaN = float32_is_signaling_nan(a, status);
bIsQuietNaN = float32_is_quiet_nan(b, status);
bIsSignalingNaN = float32_is_signaling_nan(b, status);
av = float32_val(a);
bv = float32_val(b);
if (aIsSignalingNaN | bIsSignalingNaN) {
if (is_snan(a_cls) || is_snan(b_cls)) {
float_raise(float_flag_invalid, status);
}
@ -779,14 +755,13 @@ static float32 propagateFloat32NaN(float32 a, float32 b, float_status *status)
aIsLargerSignificand = (av < bv) ? 1 : 0;
}
if (pickNaN(aIsQuietNaN, aIsSignalingNaN, bIsQuietNaN, bIsSignalingNaN,
aIsLargerSignificand)) {
if (bIsSignalingNaN) {
if (pickNaN(a_cls, b_cls, aIsLargerSignificand)) {
if (is_snan(b_cls)) {
return float32_silence_nan(b, status);
}
return b;
} else {
if (aIsSignalingNaN) {
if (is_snan(a_cls)) {
return float32_silence_nan(a, status);
}
return a;
@ -908,18 +883,26 @@ static float64 commonNaNToFloat64(commonNaNT a, float_status *status)
static float64 propagateFloat64NaN(float64 a, float64 b, float_status *status)
{
flag aIsQuietNaN, aIsSignalingNaN, bIsQuietNaN, bIsSignalingNaN;
flag aIsLargerSignificand;
uint64_t av, bv;
FloatClass a_cls, b_cls;
/* This is not complete, but is good enough for pickNaN. */
a_cls = (!float64_is_any_nan(a)
? float_class_normal
: float64_is_signaling_nan(a, status)
? float_class_snan
: float_class_qnan);
b_cls = (!float64_is_any_nan(b)
? float_class_normal
: float64_is_signaling_nan(b, status)
? float_class_snan
: float_class_qnan);
aIsQuietNaN = float64_is_quiet_nan(a, status);
aIsSignalingNaN = float64_is_signaling_nan(a, status);
bIsQuietNaN = float64_is_quiet_nan(b, status);
bIsSignalingNaN = float64_is_signaling_nan(b, status);
av = float64_val(a);
bv = float64_val(b);
if (aIsSignalingNaN | bIsSignalingNaN) {
if (is_snan(a_cls) || is_snan(b_cls)) {
float_raise(float_flag_invalid, status);
}
@ -935,14 +918,13 @@ static float64 propagateFloat64NaN(float64 a, float64 b, float_status *status)
aIsLargerSignificand = (av < bv) ? 1 : 0;
}
if (pickNaN(aIsQuietNaN, aIsSignalingNaN, bIsQuietNaN, bIsSignalingNaN,
aIsLargerSignificand)) {
if (bIsSignalingNaN) {
if (pickNaN(a_cls, b_cls, aIsLargerSignificand)) {
if (is_snan(b_cls)) {
return float64_silence_nan(b, status);
}
return b;
} else {
if (aIsSignalingNaN) {
if (is_snan(a_cls)) {
return float64_silence_nan(a, status);
}
return a;
@ -1075,15 +1057,22 @@ static floatx80 commonNaNToFloatx80(commonNaNT a, float_status *status)
floatx80 propagateFloatx80NaN(floatx80 a, floatx80 b, float_status *status)
{
flag aIsQuietNaN, aIsSignalingNaN, bIsQuietNaN, bIsSignalingNaN;
flag aIsLargerSignificand;
FloatClass a_cls, b_cls;
aIsQuietNaN = floatx80_is_quiet_nan(a, status);
aIsSignalingNaN = floatx80_is_signaling_nan(a, status);
bIsQuietNaN = floatx80_is_quiet_nan(b, status);
bIsSignalingNaN = floatx80_is_signaling_nan(b, status);
/* This is not complete, but is good enough for pickNaN. */
a_cls = (!floatx80_is_any_nan(a)
? float_class_normal
: floatx80_is_signaling_nan(a, status)
? float_class_snan
: float_class_qnan);
b_cls = (!floatx80_is_any_nan(b)
? float_class_normal
: floatx80_is_signaling_nan(b, status)
? float_class_snan
: float_class_qnan);
if (aIsSignalingNaN | bIsSignalingNaN) {
if (is_snan(a_cls) || is_snan(b_cls)) {
float_raise(float_flag_invalid, status);
}
@ -1099,14 +1088,13 @@ floatx80 propagateFloatx80NaN(floatx80 a, floatx80 b, float_status *status)
aIsLargerSignificand = (a.high < b.high) ? 1 : 0;
}
if (pickNaN(aIsQuietNaN, aIsSignalingNaN, bIsQuietNaN, bIsSignalingNaN,
aIsLargerSignificand)) {
if (bIsSignalingNaN) {
if (pickNaN(a_cls, b_cls, aIsLargerSignificand)) {
if (is_snan(b_cls)) {
return floatx80_silence_nan(b, status);
}
return b;
} else {
if (aIsSignalingNaN) {
if (is_snan(a_cls)) {
return floatx80_silence_nan(a, status);
}
return a;
@ -1217,15 +1205,22 @@ static float128 commonNaNToFloat128(commonNaNT a, float_status *status)
static float128 propagateFloat128NaN(float128 a, float128 b,
float_status *status)
{
flag aIsQuietNaN, aIsSignalingNaN, bIsQuietNaN, bIsSignalingNaN;
flag aIsLargerSignificand;
FloatClass a_cls, b_cls;
aIsQuietNaN = float128_is_quiet_nan(a, status);
aIsSignalingNaN = float128_is_signaling_nan(a, status);
bIsQuietNaN = float128_is_quiet_nan(b, status);
bIsSignalingNaN = float128_is_signaling_nan(b, status);
/* This is not complete, but is good enough for pickNaN. */
a_cls = (!float128_is_any_nan(a)
? float_class_normal
: float128_is_signaling_nan(a, status)
? float_class_snan
: float_class_qnan);
b_cls = (!float128_is_any_nan(b)
? float_class_normal
: float128_is_signaling_nan(b, status)
? float_class_snan
: float_class_qnan);
if (aIsSignalingNaN | bIsSignalingNaN) {
if (is_snan(a_cls) || is_snan(b_cls)) {
float_raise(float_flag_invalid, status);
}
@ -1241,14 +1236,13 @@ static float128 propagateFloat128NaN(float128 a, float128 b,
aIsLargerSignificand = (a.high < b.high) ? 1 : 0;
}
if (pickNaN(aIsQuietNaN, aIsSignalingNaN, bIsQuietNaN, bIsSignalingNaN,
aIsLargerSignificand)) {
if (bIsSignalingNaN) {
if (pickNaN(a_cls, b_cls, aIsLargerSignificand)) {
if (is_snan(b_cls)) {
return float128_silence_nan(b, status);
}
return b;
} else {
if (aIsSignalingNaN) {
if (is_snan(a_cls)) {
return float128_silence_nan(a, status);
}
return a;

3
fpu/softfloat.c
View file

@ -580,8 +580,7 @@ static FloatParts pick_nan(FloatParts a, FloatParts b, float_status *s)
if (s->default_nan_mode) {
return parts_default_nan(s);
} else {
if (pickNaN(is_qnan(a.cls), is_snan(a.cls),
is_qnan(b.cls), is_snan(b.cls),
if (pickNaN(a.cls, b.cls,
a.frac > b.frac ||
(a.frac == b.frac && a.sign < b.sign))) {
a = b;