1#include <math.h>
 2#include <stdint.h>
 3
 4float copysignf(float x, float y)
 5{
 6	union {float f; uint32_t i;} ux={x}, uy={y};
 7	ux.i &= 0x7fffffff;
 8	ux.i |= uy.i & 0x80000000;
 9	return ux.f;
10}