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