[CRT:MATH] Import frexp from musl

This commit is contained in:
Timo Kreuzer 2025-05-26 21:54:47 +03:00
parent b734e3ba63
commit c507b701ab

View file

@ -1,29 +1,33 @@
#include <math.h>
#include <stdlib.h>
#include <internal/ieee.h>
/*
* @implemented
* PROJECT: ReactOS CRT
* LICENSE: MIT (https://spdx.org/licenses/MIT)
* PURPOSE: Implementation of frexp
* COPYRIGHT: Imported from musl libc
* https://git.musl-libc.org/cgit/musl/tree/src/math/frexp.c
* blob: 27b6266ed0c1d7c5dadd06ecc186a994fdcd1c52
* See https://git.musl-libc.org/cgit/musl/tree/COPYRIGHT
*/
double
frexp(double __x, int *exptr)
#include <math.h>
#include <stdint.h>
double frexp(double x, int *e)
{
union
{
double* __x;
double_s* x;
} x;
union { double d; uint64_t i; } y = { x };
int ee = y.i>>52 & 0x7ff;
x.__x = &__x;
if (!ee) {
if (x) {
x = frexp(x*0x1p64, e);
*e -= 64;
} else *e = 0;
return x;
} else if (ee == 0x7ff) {
return x;
}
if ( exptr != NULL )
*exptr = x.x->exponent - 0x3FE;
x.x->exponent = 0x3FE;
return __x;
*e = ee - 0x3fe;
y.i &= 0x800fffffffffffffull;
y.i |= 0x3fe0000000000000ull;
return y.d;
}