summaryrefslogtreecommitdiff
path: root/src/math/scalbnf.c
blob: 0b62c3c71f85d4b72a21a9b39752fb77ce0caf10 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
#include <math.h>
#include <stdint.h>

float scalbnf(float x, int n)
{
	union {float f; uint32_t i;} u;
	float_t y = x;

	if (n > 127) {
		y *= 0x1p127f;
		n -= 127;
		if (n > 127) {
			y *= 0x1p127f;
			n -= 127;
			if (n > 127)
				n = 127;
		}
	} else if (n < -126) {
		y *= 0x1p-126f;
		n += 126;
		if (n < -126) {
			y *= 0x1p-126f;
			n += 126;
			if (n < -126)
				n = -126;
		}
	}
	u.i = (uint32_t)(0x7f+n)<<23;
	x = y * u.f;
	return x;
}