Edward O'Callaghan | 37a6a45 | 2009-08-07 20:30:09 +0000 | [diff] [blame] | 1 | /* ===-- fixdfti.c - Implement __fixdfti -----------------------------------=== |
| 2 | * |
| 3 | * The LLVM Compiler Infrastructure |
| 4 | * |
Howard Hinnant | 9ad441f | 2010-11-16 22:13:33 +0000 | [diff] [blame] | 5 | * This file is dual licensed under the MIT and the University of Illinois Open |
| 6 | * Source Licenses. See LICENSE.TXT for details. |
Edward O'Callaghan | 37a6a45 | 2009-08-07 20:30:09 +0000 | [diff] [blame] | 7 | * |
| 8 | * ===----------------------------------------------------------------------=== |
| 9 | * |
| 10 | * This file implements __fixdfti for the compiler_rt library. |
| 11 | * |
| 12 | * ===----------------------------------------------------------------------=== |
| 13 | */ |
Daniel Dunbar | b3a6901 | 2009-06-26 16:47:03 +0000 | [diff] [blame] | 14 | |
Daniel Dunbar | b3a6901 | 2009-06-26 16:47:03 +0000 | [diff] [blame] | 15 | #include "int_lib.h" |
| 16 | |
Chandler Carruth | 7f2d7c7 | 2012-06-22 21:09:22 +0000 | [diff] [blame^] | 17 | #if __x86_64 |
| 18 | |
Edward O'Callaghan | 37a6a45 | 2009-08-07 20:30:09 +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 | 37a6a45 | 2009-08-07 20:30:09 +0000 | [diff] [blame] | 21 | /* Assumption: double is a IEEE 64 bit floating point type |
| 22 | * su_int is a 32 bit integral type |
| 23 | * value in 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 | 37a6a45 | 2009-08-07 20:30:09 +0000 | [diff] [blame] | 26 | /* seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm */ |
Daniel Dunbar | b3a6901 | 2009-06-26 16:47:03 +0000 | [diff] [blame] | 27 | |
| 28 | ti_int |
| 29 | __fixdfti(double a) |
| 30 | { |
| 31 | double_bits fb; |
| 32 | fb.f = a; |
Edward O'Callaghan | aabd961 | 2009-09-03 09:12:20 +0000 | [diff] [blame] | 33 | int e = ((fb.u.s.high & 0x7FF00000) >> 20) - 1023; |
Daniel Dunbar | b3a6901 | 2009-06-26 16:47:03 +0000 | [diff] [blame] | 34 | if (e < 0) |
| 35 | return 0; |
Edward O'Callaghan | aabd961 | 2009-09-03 09:12:20 +0000 | [diff] [blame] | 36 | ti_int s = (si_int)(fb.u.s.high & 0x80000000) >> 31; |
Daniel Dunbar | b3a6901 | 2009-06-26 16:47:03 +0000 | [diff] [blame] | 37 | ti_int r = 0x0010000000000000uLL | (0x000FFFFFFFFFFFFFuLL & fb.u.all); |
| 38 | if (e > 52) |
| 39 | r <<= (e - 52); |
| 40 | else |
| 41 | r >>= (52 - e); |
| 42 | return (r ^ s) - s; |
| 43 | } |
| 44 | |
| 45 | #endif |