fixxfti.c revision 222656 
192108Sphk/* ===-- fixxfti.c - Implement __fixxfti -----------------------------------===
292108Sphk *
392108Sphk *      	       The LLVM Compiler Infrastructure
492108Sphk *
592108Sphk * This file is dual licensed under the MIT and the University of Illinois Open
692108Sphk * Source Licenses. See LICENSE.TXT for details.
792108Sphk *
892108Sphk * ===----------------------------------------------------------------------===
992108Sphk *
1092108Sphk * This file implements __fixxfti for the compiler_rt library.
1192108Sphk *
1292108Sphk * ===----------------------------------------------------------------------===
1392108Sphk */
1492108Sphk
1592108Sphk#if __x86_64
1692108Sphk
1792108Sphk#include "int_lib.h"
1892108Sphk
1992108Sphk/* Returns: convert a to a signed long long, rounding toward zero. */
2092108Sphk
2192108Sphk/* Assumption: long double is an intel 80 bit floating point type padded with 6 bytes
2292108Sphk *             su_int is a 32 bit integral type
2392108Sphk *             value in long double is representable in ti_int (no range checking performed)
2492108Sphk */
2592108Sphk
2692108Sphk/* gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee eeee |
2792108Sphk * 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm
2892108Sphk */
2992108Sphk
3092108Sphkti_int
3192108Sphk__fixxfti(long double a)
3292108Sphk{
3392108Sphk    long_double_bits fb;
3492108Sphk    fb.f = a;
3592108Sphk    int e = (fb.u.high.s.low & 0x00007FFF) - 16383;
3692108Sphk    if (e < 0)
3792108Sphk        return 0;
3892108Sphk    ti_int s = -(si_int)((fb.u.high.s.low & 0x00008000) >> 15);
3992108Sphk    ti_int r = fb.u.low.all;
4092108Sphk    if (e > 63)
41116196Sobrien        r <<= (e - 63);
42116196Sobrien    else
43116196Sobrien        r >>= (63 - e);
4492108Sphk    return (r ^ s) - s;
4592108Sphk}
4692108Sphk
4792108Sphk#endif /* __x86_64 */
4892108Sphk