1#define _GNU_SOURCE
2#include "libc.h"
3#include <math.h>
4#include <stdint.h>
5
6float exp10f(float x) {
7    static const float p10[] = {1e-7f, 1e-6f, 1e-5f, 1e-4f, 1e-3f, 1e-2f, 1e-1f, 1,
8                                1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7};
9    float n, y = modff(x, &n);
10    union {
11        float f;
12        uint32_t i;
13    } u = {n};
14    /* fabsf(n) < 8 without raising invalid on nan */
15    if ((u.i >> 23 & 0xff) < 0x7f + 3) {
16        if (!y)
17            return p10[(int)n + 7];
18        y = exp2f(3.32192809488736234787031942948939f * y);
19        return y * p10[(int)n + 7];
20    }
21    return exp2(3.32192809488736234787031942948939 * x);
22}
23
24weak_alias(exp10f, pow10f);
25