old code was correct only if the result was stored (without the
excess precision) or musl was compiled with -ffloat-store.
now we use STRICT_ASSIGN to work around the issue.
(see note 160 in c11 section 6.8.6.4)
-#include <math.h>
-#include <stdint.h>
double modf(double x, double *iptr)
{
double modf(double x, double *iptr)
{
}
u.n &= ~mask;
*iptr = u.x;
}
u.n &= ~mask;
*iptr = u.x;
+ STRICT_ASSIGN(double, x, x - *iptr);
+ return x;
-#include <math.h>
-#include <stdint.h>
float modff(float x, float *iptr)
{
float modff(float x, float *iptr)
{
}
u.n &= ~mask;
*iptr = u.x;
}
u.n &= ~mask;
*iptr = u.x;
+ STRICT_ASSIGN(float, x, x - *iptr);
+ return x;
double scalbn(double x, int n)
{
double scalbn(double x, int n)
{
- /* make sure result is stored as double on overflow or underflow */
- volatile double z;
double scale;
if (n > 1023) {
double scale;
if (n > 1023) {
x *= 0x1p1023;
n -= 1023;
if (n > 1023) {
x *= 0x1p1023;
n -= 1023;
if (n > 1023) {
- z = x * 0x1p1023;
- return z;
+ STRICT_ASSIGN(double, x, x * 0x1p1023);
+ return x;
}
}
} else if (n < -1022) {
}
}
} else if (n < -1022) {
x *= 0x1p-1022;
n += 1022;
if (n < -1022) {
x *= 0x1p-1022;
n += 1022;
if (n < -1022) {
- z = x * 0x1p-1022;
- return z;
+ STRICT_ASSIGN(double, x, x * 0x1p-1022);
+ return x;
}
}
}
INSERT_WORDS(scale, (uint32_t)(0x3ff+n)<<20, 0);
}
}
}
INSERT_WORDS(scale, (uint32_t)(0x3ff+n)<<20, 0);
- z = x * scale;
- return z;
+ STRICT_ASSIGN(double, x, x * scale);
+ return x;
float scalbnf(float x, int n)
{
float scalbnf(float x, int n)
{
- /* make sure result is stored as double on overflow or underflow */
- volatile float z;
float scale;
if (n > 127) {
float scale;
if (n > 127) {
x *= 0x1p127f;
n -= 127;
if (n > 127) {
x *= 0x1p127f;
n -= 127;
if (n > 127) {
- z = x * 0x1p127f;
- return z;
+ STRICT_ASSIGN(float, x, x * 0x1p127f);
+ return x;
}
}
} else if (n < -126) {
}
}
} else if (n < -126) {
x *= 0x1p-126f;
n += 126;
if (n < -126) {
x *= 0x1p-126f;
n += 126;
if (n < -126) {
- z = x * 0x1p-126f;
- return z;
+ STRICT_ASSIGN(float, x, x * 0x1p-126f);
+ return x;
}
}
}
SET_FLOAT_WORD(scale, (uint32_t)(0x7f+n)<<23);
}
}
}
SET_FLOAT_WORD(scale, (uint32_t)(0x7f+n)<<23);
- z = x * scale;
- return z;
+ STRICT_ASSIGN(float, x, x * scale);
+ return x;