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Edward O'Callaghan2bf62722009-08-05 04:02:56 +00001/* ===-- fixxfti.c - Implement __fixxfti -----------------------------------===
2 *
3 * The LLVM Compiler Infrastructure
4 *
Howard Hinnant9ad441f2010-11-16 22:13:33 +00005 * This file is dual licensed under the MIT and the University of Illinois Open
6 * Source Licenses. See LICENSE.TXT for details.
Edward O'Callaghan2bf62722009-08-05 04:02:56 +00007 *
8 * ===----------------------------------------------------------------------===
9 *
10 * This file implements __fixxfti for the compiler_rt library.
11 *
12 * ===----------------------------------------------------------------------===
13 */
Daniel Dunbarb3a69012009-06-26 16:47:03 +000014
Daniel Dunbarb3a69012009-06-26 16:47:03 +000015#include "int_lib.h"
16
Chandler Carruth7f2d7c72012-06-22 21:09:22 +000017#if __x86_64
18
Edward O'Callaghan2bf62722009-08-05 04:02:56 +000019/* Returns: convert a to a signed long long, rounding toward zero. */
Daniel Dunbarb3a69012009-06-26 16:47:03 +000020
Edward O'Callaghan2bf62722009-08-05 04:02:56 +000021/* 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 Dunbarb3a69012009-06-26 16:47:03 +000025
Edward O'Callaghan2bf62722009-08-05 04:02:56 +000026/* 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 Dunbarb3a69012009-06-26 16:47:03 +000029
30ti_int
31__fixxfti(long double a)
32{
33 long_double_bits fb;
34 fb.f = a;
Edward O'Callaghanaabd9612009-09-03 09:12:20 +000035 int e = (fb.u.high.s.low & 0x00007FFF) - 16383;
Daniel Dunbarb3a69012009-06-26 16:47:03 +000036 if (e < 0)
37 return 0;
Edward O'Callaghanaabd9612009-09-03 09:12:20 +000038 ti_int s = -(si_int)((fb.u.high.s.low & 0x00008000) >> 15);
Daniel Dunbarb3a69012009-06-26 16:47:03 +000039 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'Callaghan8bf1e092009-08-09 18:41:02 +000047#endif /* __x86_64 */