| 1 | #include <math.h> |
| 2 | #include <stdint.h> |
| 3 | |
| 4 | float scalbnf(float x, int n) |
| 5 | { |
| 6 | union {float f; uint32_t i;} u; |
| 7 | float_t y = x; |
| 8 | |
| 9 | if (n > 127) { |
| 10 | y *= 0x1p127f; |
| 11 | n -= 127; |
| 12 | if (n > 127) { |
| 13 | y *= 0x1p127f; |
| 14 | n -= 127; |
| 15 | if (n > 127) |
| 16 | n = 127; |
| 17 | } |
| 18 | } else if (n < -126) { |
| 19 | y *= 0x1p-126f * 0x1p24f; |
| 20 | n += 126 - 24; |
| 21 | if (n < -126) { |
| 22 | y *= 0x1p-126f * 0x1p24f; |
| 23 | n += 126 - 24; |
| 24 | if (n < -126) |
| 25 | n = -126; |
| 26 | } |
| 27 | } |
| 28 | u.i = (uint32_t)(0x7f+n)<<23; |
| 29 | x = y * u.f; |
| 30 | return x; |
| 31 | } |