Edward O'Callaghan | 2bf6272 | 2009-08-05 04:02:56 +0000 | [diff] [blame] | 1 | /* ===-- fixxfti.c - Implement __fixxfti -----------------------------------=== |
| 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 __fixxfti for the compiler_rt library. |
| 11 | * |
| 12 | * ===----------------------------------------------------------------------=== |
| 13 | */ |
Daniel Dunbar | b3a6901 | 2009-06-26 16:47:03 +0000 | [diff] [blame] | 14 | |
| 15 | #if __x86_64 |
| 16 | |
| 17 | #include "int_lib.h" |
| 18 | |
Edward O'Callaghan | 2bf6272 | 2009-08-05 04:02:56 +0000 | [diff] [blame] | 19 | /* Returns: convert a to a signed long long, rounding toward zero. */ |
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: long double is an intel 80 bit floating point type padded with 6 bytes |
| 22 | * su_int is a 32 bit integral type |
| 23 | * value in long double is representable in ti_int (no range checking performed) |
| 24 | */ |
Daniel Dunbar | b3a6901 | 2009-06-26 16:47:03 +0000 | [diff] [blame] | 25 | |
Edward O'Callaghan | 2bf6272 | 2009-08-05 04:02:56 +0000 | [diff] [blame] | 26 | /* gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee eeee | |
| 27 | * 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm |
| 28 | */ |
Daniel Dunbar | b3a6901 | 2009-06-26 16:47:03 +0000 | [diff] [blame] | 29 | |
| 30 | ti_int |
| 31 | __fixxfti(long double a) |
| 32 | { |
| 33 | long_double_bits fb; |
| 34 | fb.f = a; |
| 35 | int e = (fb.u.high.low & 0x00007FFF) - 16383; |
| 36 | if (e < 0) |
| 37 | return 0; |
| 38 | ti_int s = -(si_int)((fb.u.high.low & 0x00008000) >> 15); |
| 39 | ti_int r = fb.u.low.all; |
| 40 | if (e > 63) |
| 41 | r <<= (e - 63); |
| 42 | else |
| 43 | r >>= (63 - e); |
| 44 | return (r ^ s) - s; |
| 45 | } |
| 46 | |
Edward O'Callaghan | 8bf1e09 | 2009-08-09 18:41:02 +0000 | [diff] [blame^] | 47 | #endif /* __x86_64 */ |