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|
/*
* Ported from a work by Andreas Grabher for Previous, NeXT Computer Emulator,
* derived from NetBSD M68040 FPSP functions,
* derived from release 2a of the SoftFloat IEC/IEEE Floating-point Arithmetic
* Package. Those parts of the code (and some later contributions) are
* provided under that license, as detailed below.
* It has subsequently been modified by contributors to the QEMU Project,
* so some portions are provided under:
* the SoftFloat-2a license
* the BSD license
* GPL-v2-or-later
*
* Any future contributions to this file will be taken to be licensed under
* the Softfloat-2a license unless specifically indicated otherwise.
*/
/* Portions of this work are licensed under the terms of the GNU GPL,
* version 2 or later. See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "softfloat.h"
#include "fpu/softfloat-macros.h"
static floatx80 propagateFloatx80NaNOneArg(floatx80 a, float_status *status)
{
if (floatx80_is_signaling_nan(a, status)) {
float_raise(float_flag_invalid, status);
}
if (status->default_nan_mode) {
return floatx80_default_nan(status);
}
return floatx80_maybe_silence_nan(a, status);
}
/*----------------------------------------------------------------------------
| Returns the modulo remainder of the extended double-precision floating-point
| value `a' with respect to the corresponding value `b'.
*----------------------------------------------------------------------------*/
floatx80 floatx80_mod(floatx80 a, floatx80 b, float_status *status)
{
flag aSign, zSign;
int32_t aExp, bExp, expDiff;
uint64_t aSig0, aSig1, bSig;
uint64_t qTemp, term0, term1;
aSig0 = extractFloatx80Frac(a);
aExp = extractFloatx80Exp(a);
aSign = extractFloatx80Sign(a);
bSig = extractFloatx80Frac(b);
bExp = extractFloatx80Exp(b);
if (aExp == 0x7FFF) {
if ((uint64_t) (aSig0 << 1)
|| ((bExp == 0x7FFF) && (uint64_t) (bSig << 1))) {
return propagateFloatx80NaN(a, b, status);
}
goto invalid;
}
if (bExp == 0x7FFF) {
if ((uint64_t) (bSig << 1)) {
return propagateFloatx80NaN(a, b, status);
}
return a;
}
if (bExp == 0) {
if (bSig == 0) {
invalid:
float_raise(float_flag_invalid, status);
return floatx80_default_nan(status);
}
normalizeFloatx80Subnormal(bSig, &bExp, &bSig);
}
if (aExp == 0) {
if ((uint64_t) (aSig0 << 1) == 0) {
return a;
}
normalizeFloatx80Subnormal(aSig0, &aExp, &aSig0);
}
bSig |= LIT64(0x8000000000000000);
zSign = aSign;
expDiff = aExp - bExp;
aSig1 = 0;
if (expDiff < 0) {
return a;
}
qTemp = (bSig <= aSig0);
if (qTemp) {
aSig0 -= bSig;
}
expDiff -= 64;
while (0 < expDiff) {
qTemp = estimateDiv128To64(aSig0, aSig1, bSig);
qTemp = (2 < qTemp) ? qTemp - 2 : 0;
mul64To128(bSig, qTemp, &term0, &term1);
sub128(aSig0, aSig1, term0, term1, &aSig0, &aSig1);
shortShift128Left(aSig0, aSig1, 62, &aSig0, &aSig1);
}
expDiff += 64;
if (0 < expDiff) {
qTemp = estimateDiv128To64(aSig0, aSig1, bSig);
qTemp = (2 < qTemp) ? qTemp - 2 : 0;
qTemp >>= 64 - expDiff;
mul64To128(bSig, qTemp << (64 - expDiff), &term0, &term1);
sub128(aSig0, aSig1, term0, term1, &aSig0, &aSig1);
shortShift128Left(0, bSig, 64 - expDiff, &term0, &term1);
while (le128(term0, term1, aSig0, aSig1)) {
++qTemp;
sub128(aSig0, aSig1, term0, term1, &aSig0, &aSig1);
}
}
return
normalizeRoundAndPackFloatx80(
80, zSign, bExp + expDiff, aSig0, aSig1, status);
}
/*----------------------------------------------------------------------------
| Returns the mantissa of the extended double-precision floating-point
| value `a'.
*----------------------------------------------------------------------------*/
floatx80 floatx80_getman(floatx80 a, float_status *status)
{
flag aSign;
int32_t aExp;
uint64_t aSig;
aSig = extractFloatx80Frac(a);
aExp = extractFloatx80Exp(a);
aSign = extractFloatx80Sign(a);
if (aExp == 0x7FFF) {
if ((uint64_t) (aSig << 1)) {
return propagateFloatx80NaNOneArg(a , status);
}
float_raise(float_flag_invalid , status);
return floatx80_default_nan(status);
}
if (aExp == 0) {
if (aSig == 0) {
return packFloatx80(aSign, 0, 0);
}
normalizeFloatx80Subnormal(aSig, &aExp, &aSig);
}
return roundAndPackFloatx80(status->floatx80_rounding_precision, aSign,
0x3FFF, aSig, 0, status);
}
/*----------------------------------------------------------------------------
| Returns the exponent of the extended double-precision floating-point
| value `a' as an extended double-precision value.
*----------------------------------------------------------------------------*/
floatx80 floatx80_getexp(floatx80 a, float_status *status)
{
flag aSign;
int32_t aExp;
uint64_t aSig;
aSig = extractFloatx80Frac(a);
aExp = extractFloatx80Exp(a);
aSign = extractFloatx80Sign(a);
if (aExp == 0x7FFF) {
if ((uint64_t) (aSig << 1)) {
return propagateFloatx80NaNOneArg(a , status);
}
float_raise(float_flag_invalid , status);
return floatx80_default_nan(status);
}
if (aExp == 0) {
if (aSig == 0) {
return packFloatx80(aSign, 0, 0);
}
normalizeFloatx80Subnormal(aSig, &aExp, &aSig);
}
return int32_to_floatx80(aExp - 0x3FFF, status);
}
/*----------------------------------------------------------------------------
| Scales extended double-precision floating-point value in operand `a' by
| value `b'. The function truncates the value in the second operand 'b' to
| an integral value and adds that value to the exponent of the operand 'a'.
| The operation performed according to the IEC/IEEE Standard for Binary
| Floating-Point Arithmetic.
*----------------------------------------------------------------------------*/
floatx80 floatx80_scale(floatx80 a, floatx80 b, float_status *status)
{
flag aSign, bSign;
int32_t aExp, bExp, shiftCount;
uint64_t aSig, bSig;
aSig = extractFloatx80Frac(a);
aExp = extractFloatx80Exp(a);
aSign = extractFloatx80Sign(a);
bSig = extractFloatx80Frac(b);
bExp = extractFloatx80Exp(b);
bSign = extractFloatx80Sign(b);
if (bExp == 0x7FFF) {
if ((uint64_t) (bSig << 1) ||
((aExp == 0x7FFF) && (uint64_t) (aSig << 1))) {
return propagateFloatx80NaN(a, b, status);
}
float_raise(float_flag_invalid , status);
return floatx80_default_nan(status);
}
if (aExp == 0x7FFF) {
if ((uint64_t) (aSig << 1)) {
return propagateFloatx80NaN(a, b, status);
}
return packFloatx80(aSign, floatx80_infinity.high,
floatx80_infinity.low);
}
if (aExp == 0) {
if (aSig == 0) {
return packFloatx80(aSign, 0, 0);
}
if (bExp < 0x3FFF) {
return a;
}
normalizeFloatx80Subnormal(aSig, &aExp, &aSig);
}
if (bExp < 0x3FFF) {
return a;
}
if (0x400F < bExp) {
aExp = bSign ? -0x6001 : 0xE000;
return roundAndPackFloatx80(status->floatx80_rounding_precision,
aSign, aExp, aSig, 0, status);
}
shiftCount = 0x403E - bExp;
bSig >>= shiftCount;
aExp = bSign ? (aExp - bSig) : (aExp + bSig);
return roundAndPackFloatx80(status->floatx80_rounding_precision,
aSign, aExp, aSig, 0, status);
}
|
