1#include <math.h>
2#include <stdint.h>
3
4float fmodf(float x, float y)
5{
6	union {float f; uint32_t i;} ux = {x}, uy = {y};
7	int ex = ux.i>>23 & 0xff;
8	int ey = uy.i>>23 & 0xff;
9	uint32_t sx = ux.i & 0x80000000;
10	uint32_t i;
11	uint32_t uxi = ux.i;
12
13	if (uy.i<<1 == 0 || isnan(y) || ex == 0xff)
14		return (x*y)/(x*y);
15	if (uxi<<1 <= uy.i<<1) {
16		if (uxi<<1 == uy.i<<1)
17			return 0*x;
18		return x;
19	}
20
21	/* normalize x and y */
22	if (!ex) {
23		for (i = uxi<<9; i>>31 == 0; ex--, i <<= 1);
24		uxi <<= -ex + 1;
25	} else {
26		uxi &= -1U >> 9;
27		uxi |= 1U << 23;
28	}
29	if (!ey) {
30		for (i = uy.i<<9; i>>31 == 0; ey--, i <<= 1);
31		uy.i <<= -ey + 1;
32	} else {
33		uy.i &= -1U >> 9;
34		uy.i |= 1U << 23;
35	}
36
37	/* x mod y */
38	for (; ex > ey; ex--) {
39		i = uxi - uy.i;
40		if (i >> 31 == 0) {
41			if (i == 0)
42				return 0*x;
43			uxi = i;
44		}
45		uxi <<= 1;
46	}
47	i = uxi - uy.i;
48	if (i >> 31 == 0) {
49		if (i == 0)
50			return 0*x;
51		uxi = i;
52	}
53	for (; uxi>>23 == 0; uxi <<= 1, ex--);
54
55	/* scale result up */
56	if (ex > 0) {
57		uxi -= 1U << 23;
58		uxi |= (uint32_t)ex << 23;
59	} else {
60		uxi >>= -ex + 1;
61	}
62	uxi |= sx;
63	ux.i = uxi;
64	return ux.f;
65}
66