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softfloat: Implement fused multiply-add

Implement fused multiply-add as a softfloat primitive. This implements
"a+b*c" as a single step without any intermediate rounding; it is
specified in IEEE 754-2008 and implemented in a number of CPUs.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Peter Maydell 2011-10-19 16:14:06 +00:00
parent b8b8ea05c4
commit 369be8f618
3 changed files with 619 additions and 0 deletions

View File

@ -419,6 +419,82 @@ static int pickNaN(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN,
}
#endif
/*----------------------------------------------------------------------------
| Select which NaN to propagate for a three-input operation.
| For the moment we assume that no CPU needs the 'larger significand'
| information.
| Return values : 0 : a; 1 : b; 2 : c; 3 : default-NaN
*----------------------------------------------------------------------------*/
#if defined(TARGET_ARM)
static int pickNaNMulAdd(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN,
flag cIsQNaN, flag cIsSNaN, flag infzero STATUS_PARAM)
{
/* For ARM, the (inf,zero,qnan) case sets InvalidOp and returns
* the default NaN
*/
if (infzero && cIsQNaN) {
float_raise(float_flag_invalid STATUS_VAR);
return 3;
}
/* This looks different from the ARM ARM pseudocode, because the ARM ARM
* puts the operands to a fused mac operation (a*b)+c in the order c,a,b.
*/
if (cIsSNaN) {
return 2;
} else if (aIsSNaN) {
return 0;
} else if (bIsSNaN) {
return 1;
} else if (cIsQNaN) {
return 2;
} else if (aIsQNaN) {
return 0;
} else {
return 1;
}
}
#elif defined(TARGET_PPC)
static int pickNaNMulAdd(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN,
flag cIsQNaN, flag cIsSNaN, flag infzero STATUS_PARAM)
{
/* For PPC, the (inf,zero,qnan) case sets InvalidOp, but we prefer
* to return an input NaN if we have one (ie c) rather than generating
* a default NaN
*/
if (infzero) {
float_raise(float_flag_invalid STATUS_VAR);
return 2;
}
/* If fRA is a NaN return it; otherwise if fRB is a NaN return it;
* otherwise return fRC. Note that muladd on PPC is (fRA * fRC) + frB
*/
if (aIsSNaN || aIsQNaN) {
return 0;
} else if (cIsSNaN || cIsQNaN) {
return 2;
} else {
return 1;
}
}
#else
/* A default implementation: prefer a to b to c.
* This is unlikely to actually match any real implementation.
*/
static int pickNaNMulAdd(flag aIsQNaN, flag aIsSNaN, flag bIsQNaN, flag bIsSNaN,
flag cIsQNaN, flag cIsSNaN, flag infzero STATUS_PARAM)
{
if (aIsSNaN || aIsQNaN) {
return 0;
} else if (bIsSNaN || bIsQNaN) {
return 1;
} else {
return 2;
}
}
#endif
/*----------------------------------------------------------------------------
| Takes two single-precision floating-point values `a' and `b', one of which
| is a NaN, and returns the appropriate NaN result. If either `a' or `b' is a
@ -459,6 +535,57 @@ static float32 propagateFloat32NaN( float32 a, float32 b STATUS_PARAM)
}
}
/*----------------------------------------------------------------------------
| Takes three single-precision floating-point values `a', `b' and `c', one of
| which is a NaN, and returns the appropriate NaN result. If any of `a',
| `b' or `c' is a signaling NaN, the invalid exception is raised.
| The input infzero indicates whether a*b was 0*inf or inf*0 (in which case
| obviously c is a NaN, and whether to propagate c or some other NaN is
| implementation defined).
*----------------------------------------------------------------------------*/
static float32 propagateFloat32MulAddNaN(float32 a, float32 b,
float32 c, flag infzero STATUS_PARAM)
{
flag aIsQuietNaN, aIsSignalingNaN, bIsQuietNaN, bIsSignalingNaN,
cIsQuietNaN, cIsSignalingNaN;
int which;
aIsQuietNaN = float32_is_quiet_nan(a);
aIsSignalingNaN = float32_is_signaling_nan(a);
bIsQuietNaN = float32_is_quiet_nan(b);
bIsSignalingNaN = float32_is_signaling_nan(b);
cIsQuietNaN = float32_is_quiet_nan(c);
cIsSignalingNaN = float32_is_signaling_nan(c);
if (aIsSignalingNaN | bIsSignalingNaN | cIsSignalingNaN) {
float_raise(float_flag_invalid STATUS_VAR);
}
which = pickNaNMulAdd(aIsQuietNaN, aIsSignalingNaN,
bIsQuietNaN, bIsSignalingNaN,
cIsQuietNaN, cIsSignalingNaN, infzero STATUS_VAR);
if (STATUS(default_nan_mode)) {
/* Note that this check is after pickNaNMulAdd so that function
* has an opportunity to set the Invalid flag.
*/
return float32_default_nan;
}
switch (which) {
case 0:
return float32_maybe_silence_nan(a);
case 1:
return float32_maybe_silence_nan(b);
case 2:
return float32_maybe_silence_nan(c);
case 3:
default:
return float32_default_nan;
}
}
/*----------------------------------------------------------------------------
| Returns 1 if the double-precision floating-point value `a' is a quiet
| NaN; otherwise returns 0.
@ -595,6 +722,57 @@ static float64 propagateFloat64NaN( float64 a, float64 b STATUS_PARAM)
}
}
/*----------------------------------------------------------------------------
| Takes three double-precision floating-point values `a', `b' and `c', one of
| which is a NaN, and returns the appropriate NaN result. If any of `a',
| `b' or `c' is a signaling NaN, the invalid exception is raised.
| The input infzero indicates whether a*b was 0*inf or inf*0 (in which case
| obviously c is a NaN, and whether to propagate c or some other NaN is
| implementation defined).
*----------------------------------------------------------------------------*/
static float64 propagateFloat64MulAddNaN(float64 a, float64 b,
float64 c, flag infzero STATUS_PARAM)
{
flag aIsQuietNaN, aIsSignalingNaN, bIsQuietNaN, bIsSignalingNaN,
cIsQuietNaN, cIsSignalingNaN;
int which;
aIsQuietNaN = float64_is_quiet_nan(a);
aIsSignalingNaN = float64_is_signaling_nan(a);
bIsQuietNaN = float64_is_quiet_nan(b);
bIsSignalingNaN = float64_is_signaling_nan(b);
cIsQuietNaN = float64_is_quiet_nan(c);
cIsSignalingNaN = float64_is_signaling_nan(c);
if (aIsSignalingNaN | bIsSignalingNaN | cIsSignalingNaN) {
float_raise(float_flag_invalid STATUS_VAR);
}
which = pickNaNMulAdd(aIsQuietNaN, aIsSignalingNaN,
bIsQuietNaN, bIsSignalingNaN,
cIsQuietNaN, cIsSignalingNaN, infzero STATUS_VAR);
if (STATUS(default_nan_mode)) {
/* Note that this check is after pickNaNMulAdd so that function
* has an opportunity to set the Invalid flag.
*/
return float64_default_nan;
}
switch (which) {
case 0:
return float64_maybe_silence_nan(a);
case 1:
return float64_maybe_silence_nan(b);
case 2:
return float64_maybe_silence_nan(c);
case 3:
default:
return float64_default_nan;
}
}
/*----------------------------------------------------------------------------
| Returns 1 if the extended double-precision floating-point value `a' is a
| quiet NaN; otherwise returns 0. This slightly differs from the same

View File

@ -2117,6 +2117,213 @@ float32 float32_rem( float32 a, float32 b STATUS_PARAM )
}
/*----------------------------------------------------------------------------
| Returns the result of multiplying the single-precision floating-point values
| `a' and `b' then adding 'c', with no intermediate rounding step after the
| multiplication. The operation is performed according to the IEC/IEEE
| Standard for Binary Floating-Point Arithmetic 754-2008.
| The flags argument allows the caller to select negation of the
| addend, the intermediate product, or the final result. (The difference
| between this and having the caller do a separate negation is that negating
| externally will flip the sign bit on NaNs.)
*----------------------------------------------------------------------------*/
float32 float32_muladd(float32 a, float32 b, float32 c, int flags STATUS_PARAM)
{
flag aSign, bSign, cSign, zSign;
int aExp, bExp, cExp, pExp, zExp, expDiff;
uint32_t aSig, bSig, cSig;
flag pInf, pZero, pSign;
uint64_t pSig64, cSig64, zSig64;
uint32_t pSig;
int shiftcount;
flag signflip, infzero;
a = float32_squash_input_denormal(a STATUS_VAR);
b = float32_squash_input_denormal(b STATUS_VAR);
c = float32_squash_input_denormal(c STATUS_VAR);
aSig = extractFloat32Frac(a);
aExp = extractFloat32Exp(a);
aSign = extractFloat32Sign(a);
bSig = extractFloat32Frac(b);
bExp = extractFloat32Exp(b);
bSign = extractFloat32Sign(b);
cSig = extractFloat32Frac(c);
cExp = extractFloat32Exp(c);
cSign = extractFloat32Sign(c);
infzero = ((aExp == 0 && aSig == 0 && bExp == 0xff && bSig == 0) ||
(aExp == 0xff && aSig == 0 && bExp == 0 && bSig == 0));
/* It is implementation-defined whether the cases of (0,inf,qnan)
* and (inf,0,qnan) raise InvalidOperation or not (and what QNaN
* they return if they do), so we have to hand this information
* off to the target-specific pick-a-NaN routine.
*/
if (((aExp == 0xff) && aSig) ||
((bExp == 0xff) && bSig) ||
((cExp == 0xff) && cSig)) {
return propagateFloat32MulAddNaN(a, b, c, infzero STATUS_VAR);
}
if (infzero) {
float_raise(float_flag_invalid STATUS_VAR);
return float32_default_nan;
}
if (flags & float_muladd_negate_c) {
cSign ^= 1;
}
signflip = (flags & float_muladd_negate_result) ? 1 : 0;
/* Work out the sign and type of the product */
pSign = aSign ^ bSign;
if (flags & float_muladd_negate_product) {
pSign ^= 1;
}
pInf = (aExp == 0xff) || (bExp == 0xff);
pZero = ((aExp | aSig) == 0) || ((bExp | bSig) == 0);
if (cExp == 0xff) {
if (pInf && (pSign ^ cSign)) {
/* addition of opposite-signed infinities => InvalidOperation */
float_raise(float_flag_invalid STATUS_VAR);
return float32_default_nan;
}
/* Otherwise generate an infinity of the same sign */
return packFloat32(cSign ^ signflip, 0xff, 0);
}
if (pInf) {
return packFloat32(pSign ^ signflip, 0xff, 0);
}
if (pZero) {
if (cExp == 0) {
if (cSig == 0) {
/* Adding two exact zeroes */
if (pSign == cSign) {
zSign = pSign;
} else if (STATUS(float_rounding_mode) == float_round_down) {
zSign = 1;
} else {
zSign = 0;
}
return packFloat32(zSign ^ signflip, 0, 0);
}
/* Exact zero plus a denorm */
if (STATUS(flush_to_zero)) {
float_raise(float_flag_output_denormal STATUS_VAR);
return packFloat32(cSign ^ signflip, 0, 0);
}
}
/* Zero plus something non-zero : just return the something */
return c ^ (signflip << 31);
}
if (aExp == 0) {
normalizeFloat32Subnormal(aSig, &aExp, &aSig);
}
if (bExp == 0) {
normalizeFloat32Subnormal(bSig, &bExp, &bSig);
}
/* Calculate the actual result a * b + c */
/* Multiply first; this is easy. */
/* NB: we subtract 0x7e where float32_mul() subtracts 0x7f
* because we want the true exponent, not the "one-less-than"
* flavour that roundAndPackFloat32() takes.
*/
pExp = aExp + bExp - 0x7e;
aSig = (aSig | 0x00800000) << 7;
bSig = (bSig | 0x00800000) << 8;
pSig64 = (uint64_t)aSig * bSig;
if ((int64_t)(pSig64 << 1) >= 0) {
pSig64 <<= 1;
pExp--;
}
zSign = pSign ^ signflip;
/* Now pSig64 is the significand of the multiply, with the explicit bit in
* position 62.
*/
if (cExp == 0) {
if (!cSig) {
/* Throw out the special case of c being an exact zero now */
shift64RightJamming(pSig64, 32, &pSig64);
pSig = pSig64;
return roundAndPackFloat32(zSign, pExp - 1,
pSig STATUS_VAR);
}
normalizeFloat32Subnormal(cSig, &cExp, &cSig);
}
cSig64 = (uint64_t)cSig << (62 - 23);
cSig64 |= LIT64(0x4000000000000000);
expDiff = pExp - cExp;
if (pSign == cSign) {
/* Addition */
if (expDiff > 0) {
/* scale c to match p */
shift64RightJamming(cSig64, expDiff, &cSig64);
zExp = pExp;
} else if (expDiff < 0) {
/* scale p to match c */
shift64RightJamming(pSig64, -expDiff, &pSig64);
zExp = cExp;
} else {
/* no scaling needed */
zExp = cExp;
}
/* Add significands and make sure explicit bit ends up in posn 62 */
zSig64 = pSig64 + cSig64;
if ((int64_t)zSig64 < 0) {
shift64RightJamming(zSig64, 1, &zSig64);
} else {
zExp--;
}
} else {
/* Subtraction */
if (expDiff > 0) {
shift64RightJamming(cSig64, expDiff, &cSig64);
zSig64 = pSig64 - cSig64;
zExp = pExp;
} else if (expDiff < 0) {
shift64RightJamming(pSig64, -expDiff, &pSig64);
zSig64 = cSig64 - pSig64;
zExp = cExp;
zSign ^= 1;
} else {
zExp = pExp;
if (cSig64 < pSig64) {
zSig64 = pSig64 - cSig64;
} else if (pSig64 < cSig64) {
zSig64 = cSig64 - pSig64;
zSign ^= 1;
} else {
/* Exact zero */
zSign = signflip;
if (STATUS(float_rounding_mode) == float_round_down) {
zSign ^= 1;
}
return packFloat32(zSign, 0, 0);
}
}
--zExp;
/* Normalize to put the explicit bit back into bit 62. */
shiftcount = countLeadingZeros64(zSig64) - 1;
zSig64 <<= shiftcount;
zExp -= shiftcount;
}
shift64RightJamming(zSig64, 32, &zSig64);
return roundAndPackFloat32(zSign, zExp, zSig64 STATUS_VAR);
}
/*----------------------------------------------------------------------------
| Returns the square root of the single-precision floating-point value `a'.
| The operation is performed according to the IEC/IEEE Standard for Binary
@ -3464,6 +3671,226 @@ float64 float64_rem( float64 a, float64 b STATUS_PARAM )
}
/*----------------------------------------------------------------------------
| Returns the result of multiplying the double-precision floating-point values
| `a' and `b' then adding 'c', with no intermediate rounding step after the
| multiplication. The operation is performed according to the IEC/IEEE
| Standard for Binary Floating-Point Arithmetic 754-2008.
| The flags argument allows the caller to select negation of the
| addend, the intermediate product, or the final result. (The difference
| between this and having the caller do a separate negation is that negating
| externally will flip the sign bit on NaNs.)
*----------------------------------------------------------------------------*/
float64 float64_muladd(float64 a, float64 b, float64 c, int flags STATUS_PARAM)
{
flag aSign, bSign, cSign, zSign;
int aExp, bExp, cExp, pExp, zExp, expDiff;
uint64_t aSig, bSig, cSig;
flag pInf, pZero, pSign;
uint64_t pSig0, pSig1, cSig0, cSig1, zSig0, zSig1;
int shiftcount;
flag signflip, infzero;
a = float64_squash_input_denormal(a STATUS_VAR);
b = float64_squash_input_denormal(b STATUS_VAR);
c = float64_squash_input_denormal(c STATUS_VAR);
aSig = extractFloat64Frac(a);
aExp = extractFloat64Exp(a);
aSign = extractFloat64Sign(a);
bSig = extractFloat64Frac(b);
bExp = extractFloat64Exp(b);
bSign = extractFloat64Sign(b);
cSig = extractFloat64Frac(c);
cExp = extractFloat64Exp(c);
cSign = extractFloat64Sign(c);
infzero = ((aExp == 0 && aSig == 0 && bExp == 0x7ff && bSig == 0) ||
(aExp == 0x7ff && aSig == 0 && bExp == 0 && bSig == 0));
/* It is implementation-defined whether the cases of (0,inf,qnan)
* and (inf,0,qnan) raise InvalidOperation or not (and what QNaN
* they return if they do), so we have to hand this information
* off to the target-specific pick-a-NaN routine.
*/
if (((aExp == 0x7ff) && aSig) ||
((bExp == 0x7ff) && bSig) ||
((cExp == 0x7ff) && cSig)) {
return propagateFloat64MulAddNaN(a, b, c, infzero STATUS_VAR);
}
if (infzero) {
float_raise(float_flag_invalid STATUS_VAR);
return float64_default_nan;
}
if (flags & float_muladd_negate_c) {
cSign ^= 1;
}
signflip = (flags & float_muladd_negate_result) ? 1 : 0;
/* Work out the sign and type of the product */
pSign = aSign ^ bSign;
if (flags & float_muladd_negate_product) {
pSign ^= 1;
}
pInf = (aExp == 0x7ff) || (bExp == 0x7ff);
pZero = ((aExp | aSig) == 0) || ((bExp | bSig) == 0);
if (cExp == 0x7ff) {
if (pInf && (pSign ^ cSign)) {
/* addition of opposite-signed infinities => InvalidOperation */
float_raise(float_flag_invalid STATUS_VAR);
return float64_default_nan;
}
/* Otherwise generate an infinity of the same sign */
return packFloat64(cSign ^ signflip, 0x7ff, 0);
}
if (pInf) {
return packFloat64(pSign ^ signflip, 0x7ff, 0);
}
if (pZero) {
if (cExp == 0) {
if (cSig == 0) {
/* Adding two exact zeroes */
if (pSign == cSign) {
zSign = pSign;
} else if (STATUS(float_rounding_mode) == float_round_down) {
zSign = 1;
} else {
zSign = 0;
}
return packFloat64(zSign ^ signflip, 0, 0);
}
/* Exact zero plus a denorm */
if (STATUS(flush_to_zero)) {
float_raise(float_flag_output_denormal STATUS_VAR);
return packFloat64(cSign ^ signflip, 0, 0);
}
}
/* Zero plus something non-zero : just return the something */
return c ^ ((uint64_t)signflip << 63);
}
if (aExp == 0) {
normalizeFloat64Subnormal(aSig, &aExp, &aSig);
}
if (bExp == 0) {
normalizeFloat64Subnormal(bSig, &bExp, &bSig);
}
/* Calculate the actual result a * b + c */
/* Multiply first; this is easy. */
/* NB: we subtract 0x3fe where float64_mul() subtracts 0x3ff
* because we want the true exponent, not the "one-less-than"
* flavour that roundAndPackFloat64() takes.
*/
pExp = aExp + bExp - 0x3fe;
aSig = (aSig | LIT64(0x0010000000000000))<<10;
bSig = (bSig | LIT64(0x0010000000000000))<<11;
mul64To128(aSig, bSig, &pSig0, &pSig1);
if ((int64_t)(pSig0 << 1) >= 0) {
shortShift128Left(pSig0, pSig1, 1, &pSig0, &pSig1);
pExp--;
}
zSign = pSign ^ signflip;
/* Now [pSig0:pSig1] is the significand of the multiply, with the explicit
* bit in position 126.
*/
if (cExp == 0) {
if (!cSig) {
/* Throw out the special case of c being an exact zero now */
shift128RightJamming(pSig0, pSig1, 64, &pSig0, &pSig1);
return roundAndPackFloat64(zSign, pExp - 1,
pSig1 STATUS_VAR);
}
normalizeFloat64Subnormal(cSig, &cExp, &cSig);
}
/* Shift cSig and add the explicit bit so [cSig0:cSig1] is the
* significand of the addend, with the explicit bit in position 126.
*/
cSig0 = cSig << (126 - 64 - 52);
cSig1 = 0;
cSig0 |= LIT64(0x4000000000000000);
expDiff = pExp - cExp;
if (pSign == cSign) {
/* Addition */
if (expDiff > 0) {
/* scale c to match p */
shift128RightJamming(cSig0, cSig1, expDiff, &cSig0, &cSig1);
zExp = pExp;
} else if (expDiff < 0) {
/* scale p to match c */
shift128RightJamming(pSig0, pSig1, -expDiff, &pSig0, &pSig1);
zExp = cExp;
} else {
/* no scaling needed */
zExp = cExp;
}
/* Add significands and make sure explicit bit ends up in posn 126 */
add128(pSig0, pSig1, cSig0, cSig1, &zSig0, &zSig1);
if ((int64_t)zSig0 < 0) {
shift128RightJamming(zSig0, zSig1, 1, &zSig0, &zSig1);
} else {
zExp--;
}
shift128RightJamming(zSig0, zSig1, 64, &zSig0, &zSig1);
return roundAndPackFloat64(zSign, zExp, zSig1 STATUS_VAR);
} else {
/* Subtraction */
if (expDiff > 0) {
shift128RightJamming(cSig0, cSig1, expDiff, &cSig0, &cSig1);
sub128(pSig0, pSig1, cSig0, cSig1, &zSig0, &zSig1);
zExp = pExp;
} else if (expDiff < 0) {
shift128RightJamming(pSig0, pSig1, -expDiff, &pSig0, &pSig1);
sub128(cSig0, cSig1, pSig0, pSig1, &zSig0, &zSig1);
zExp = cExp;
zSign ^= 1;
} else {
zExp = pExp;
if (lt128(cSig0, cSig1, pSig0, pSig1)) {
sub128(pSig0, pSig1, cSig0, cSig1, &zSig0, &zSig1);
} else if (lt128(pSig0, pSig1, cSig0, cSig1)) {
sub128(cSig0, cSig1, pSig0, pSig1, &zSig0, &zSig1);
zSign ^= 1;
} else {
/* Exact zero */
zSign = signflip;
if (STATUS(float_rounding_mode) == float_round_down) {
zSign ^= 1;
}
return packFloat64(zSign, 0, 0);
}
}
--zExp;
/* Do the equivalent of normalizeRoundAndPackFloat64() but
* starting with the significand in a pair of uint64_t.
*/
if (zSig0) {
shiftcount = countLeadingZeros64(zSig0) - 1;
shortShift128Left(zSig0, zSig1, shiftcount, &zSig0, &zSig1);
if (zSig1) {
zSig0 |= 1;
}
zExp -= shiftcount;
} else {
shiftcount = countLeadingZeros64(zSig1) - 1;
zSig0 = zSig1 << shiftcount;
zExp -= (shiftcount + 64);
}
return roundAndPackFloat64(zSign, zExp, zSig0 STATUS_VAR);
}
}
/*----------------------------------------------------------------------------
| Returns the square root of the double-precision floating-point value `a'.
| The operation is performed according to the IEC/IEEE Standard for Binary

View File

@ -211,6 +211,18 @@ void set_floatx80_rounding_precision(int val STATUS_PARAM);
*----------------------------------------------------------------------------*/
void float_raise( int8 flags STATUS_PARAM);
/*----------------------------------------------------------------------------
| Options to indicate which negations to perform in float*_muladd()
| Using these differs from negating an input or output before calling
| the muladd function in that this means that a NaN doesn't have its
| sign bit inverted before it is propagated.
*----------------------------------------------------------------------------*/
enum {
float_muladd_negate_c = 1,
float_muladd_negate_product = 2,
float_muladd_negate_result = 3,
};
/*----------------------------------------------------------------------------
| Software IEC/IEEE integer-to-floating-point conversion routines.
*----------------------------------------------------------------------------*/
@ -269,6 +281,7 @@ float32 float32_sub( float32, float32 STATUS_PARAM );
float32 float32_mul( float32, float32 STATUS_PARAM );
float32 float32_div( float32, float32 STATUS_PARAM );
float32 float32_rem( float32, float32 STATUS_PARAM );
float32 float32_muladd(float32, float32, float32, int STATUS_PARAM);
float32 float32_sqrt( float32 STATUS_PARAM );
float32 float32_exp2( float32 STATUS_PARAM );
float32 float32_log2( float32 STATUS_PARAM );
@ -375,6 +388,7 @@ float64 float64_sub( float64, float64 STATUS_PARAM );
float64 float64_mul( float64, float64 STATUS_PARAM );
float64 float64_div( float64, float64 STATUS_PARAM );
float64 float64_rem( float64, float64 STATUS_PARAM );
float64 float64_muladd(float64, float64, float64, int STATUS_PARAM);
float64 float64_sqrt( float64 STATUS_PARAM );
float64 float64_log2( float64 STATUS_PARAM );
int float64_eq( float64, float64 STATUS_PARAM );