Daniel Dunbar | b3a6901 | 2009-06-26 16:47:03 +0000 | [diff] [blame^] | 1 | //===-- fixunssfdi.c - Implement __fixunssfdi -----------------------------===// |
| 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 __fixunssfdi for the compiler_rt library. |
| 11 | // |
| 12 | //===----------------------------------------------------------------------===// |
| 13 | |
| 14 | #include "int_lib.h" |
| 15 | |
| 16 | // Returns: convert a to a unsigned long long, rounding toward zero. |
| 17 | // Negative values all become zero. |
| 18 | |
| 19 | // Assumption: float is a IEEE 32 bit floating point type |
| 20 | // du_int is a 64 bit integral type |
| 21 | // value in float is representable in du_int or is negative |
| 22 | // (no range checking performed) |
| 23 | |
| 24 | // seee eeee emmm mmmm mmmm mmmm mmmm mmmm |
| 25 | |
| 26 | du_int |
| 27 | __fixunssfdi(float a) |
| 28 | { |
| 29 | float_bits fb; |
| 30 | fb.f = a; |
| 31 | int e = ((fb.u & 0x7F800000) >> 23) - 127; |
| 32 | if (e < 0 || (fb.u & 0x80000000)) |
| 33 | return 0; |
| 34 | du_int r = (fb.u & 0x007FFFFF) | 0x00800000; |
| 35 | if (e > 23) |
| 36 | r <<= (e - 23); |
| 37 | else |
| 38 | r >>= (23 - e); |
| 39 | return r; |
| 40 | } |