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