nsz
8051e08e10
The old scalbn.c was wrong and slow, the new one is just slow. (scalbn(0x1p+1023,-2097) should give 0x1p-1074, but the old code gave 0)
29 lines
441 B
C
29 lines
441 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)
|
|
return x * 0x1p1023;
|
|
}
|
|
} else if (n < -1022) {
|
|
x *= 0x1p-1022;
|
|
n += 1022;
|
|
if (n < -1022) {
|
|
x *= 0x1p-1022;
|
|
n += 1022;
|
|
if (n < -1022)
|
|
return x * 0x1p-1022;
|
|
}
|
|
}
|
|
INSERT_WORDS(scale, (uint32_t)(0x3ff+n)<<20, 0);
|
|
return x * scale;
|
|
}
|