Edward O'Callaghan | 2bf6272 | 2009-08-05 04:02:56 +0000 | [diff] [blame] | 1 | /* ===-- fixunssfsi.c - Implement __fixunssfsi -----------------------------=== |
| 2 | * |
| 3 | * The LLVM Compiler Infrastructure |
| 4 | * |
| 5 | * This file is distributed under the University of Illinois Open Source |
| 6 | * License. See LICENSE.TXT for details. |
| 7 | * |
| 8 | * ===----------------------------------------------------------------------=== |
| 9 | * |
| 10 | * This file implements __fixunssfsi for the compiler_rt library. |
| 11 | * |
| 12 | * ===----------------------------------------------------------------------=== |
| 13 | */ |
Daniel Dunbar | b3a6901 | 2009-06-26 16:47:03 +0000 | [diff] [blame] | 14 | |
| 15 | #include "int_lib.h" |
| 16 | |
Edward O'Callaghan | 2bf6272 | 2009-08-05 04:02:56 +0000 | [diff] [blame] | 17 | /* Returns: convert a to a unsigned int, rounding toward zero. |
| 18 | * Negative values all become zero. |
| 19 | */ |
Daniel Dunbar | b3a6901 | 2009-06-26 16:47:03 +0000 | [diff] [blame] | 20 | |
Edward O'Callaghan | 2bf6272 | 2009-08-05 04:02:56 +0000 | [diff] [blame] | 21 | /* Assumption: float is a IEEE 32 bit floating point type |
| 22 | * su_int is a 32 bit integral type |
| 23 | * value in float is representable in su_int or is negative |
| 24 | * (no range checking performed) |
| 25 | */ |
Daniel Dunbar | b3a6901 | 2009-06-26 16:47:03 +0000 | [diff] [blame] | 26 | |
Edward O'Callaghan | 2bf6272 | 2009-08-05 04:02:56 +0000 | [diff] [blame] | 27 | /* seee eeee emmm mmmm mmmm mmmm mmmm mmmm */ |
Daniel Dunbar | b3a6901 | 2009-06-26 16:47:03 +0000 | [diff] [blame] | 28 | |
| 29 | su_int |
| 30 | __fixunssfsi(float a) |
| 31 | { |
| 32 | float_bits fb; |
| 33 | fb.f = a; |
| 34 | int e = ((fb.u & 0x7F800000) >> 23) - 127; |
| 35 | if (e < 0 || (fb.u & 0x80000000)) |
| 36 | return 0; |
| 37 | su_int r = (fb.u & 0x007FFFFF) | 0x00800000; |
| 38 | if (e > 23) |
| 39 | r <<= (e - 23); |
| 40 | else |
| 41 | r >>= (23 - e); |
| 42 | return r; |
| 43 | } |