mirror of
git://git.musl-libc.org/musl
synced 2025-04-04 23:30:14 +00:00
c4359e0130
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)
34 lines
551 B
C
34 lines
551 B
C
#include "libm.h"
|
|
|
|
double scalbn(double x, int n)
|
|
{
|
|
double scale;
|
|
|
|
if (n > 1023) {
|
|
x *= 0x1p1023;
|
|
n -= 1023;
|
|
if (n > 1023) {
|
|
x *= 0x1p1023;
|
|
n -= 1023;
|
|
if (n > 1023) {
|
|
STRICT_ASSIGN(double, x, x * 0x1p1023);
|
|
return x;
|
|
}
|
|
}
|
|
} else if (n < -1022) {
|
|
x *= 0x1p-1022;
|
|
n += 1022;
|
|
if (n < -1022) {
|
|
x *= 0x1p-1022;
|
|
n += 1022;
|
|
if (n < -1022) {
|
|
STRICT_ASSIGN(double, x, x * 0x1p-1022);
|
|
return x;
|
|
}
|
|
}
|
|
}
|
|
INSERT_WORDS(scale, (uint32_t)(0x3ff+n)<<20, 0);
|
|
STRICT_ASSIGN(double, x, x * scale);
|
|
return x;
|
|
}
|