| Rich Felker | f681975 | 2012-04-30 03:26:53 -0400 | [diff] [blame] | 1 | #define _GNU_SOURCE |
| 2 | #include <math.h> |
| Szabolcs Nagy | 18daae3 | 2014-09-18 17:02:24 +0200 | [diff] [blame] | 3 | #include <stdint.h> |
| Rich Felker | a917c03 | 2012-05-01 00:07:37 -0400 | [diff] [blame] | 4 | #include "libc.h" |
| Rich Felker | f681975 | 2012-04-30 03:26:53 -0400 | [diff] [blame] | 5 | |
| 6 | float exp10f(float x) |
| 7 | { |
| 8 | static const float p10[] = { |
| Szabolcs Nagy | a764db9 | 2012-11-18 03:52:29 +0100 | [diff] [blame] | 9 | 1e-7f, 1e-6f, 1e-5f, 1e-4f, 1e-3f, 1e-2f, 1e-1f, |
| Rich Felker | f681975 | 2012-04-30 03:26:53 -0400 | [diff] [blame] | 10 | 1, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7 |
| 11 | }; |
| 12 | float n, y = modff(x, &n); |
| Szabolcs Nagy | 18daae3 | 2014-09-18 17:02:24 +0200 | [diff] [blame] | 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) { |
| Rich Felker | f681975 | 2012-04-30 03:26:53 -0400 | [diff] [blame] | 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 | } |
| Rich Felker | a917c03 | 2012-05-01 00:07:37 -0400 | [diff] [blame] | 22 | |
| 23 | weak_alias(exp10f, pow10f); |