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      1 /* ===-- fixxfdi.c - Implement __fixxfdi -----------------------------------===
      2  *
      3  *      	       The LLVM Compiler Infrastructure
      4  *
      5  * This file is dual licensed under the MIT and the University of Illinois Open
      6  * Source Licenses. See LICENSE.TXT for details.
      7  *
      8  * ===----------------------------------------------------------------------===
      9  *
     10  * This file implements __fixxfdi for the compiler_rt library.
     11  *
     12  * ===----------------------------------------------------------------------===
     13  */
     14 
     15 #if !_ARCH_PPC
     16 
     17 #include "int_lib.h"
     18 
     19 /* Returns: convert a to a signed long long, rounding toward zero. */
     20 
     21 /* Assumption: long double is an intel 80 bit floating point type padded with 6 bytes
     22  *             di_int is a 64 bit integral type
     23  *             value in long double is representable in di_int (no range checking performed)
     24  */
     25 
     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  */
     29 
     30 COMPILER_RT_ABI di_int
     31 __fixxfdi(long double a)
     32 {
     33     const di_int di_max = (di_int)((~(du_int)0) / 2);
     34     const di_int di_min = -di_max - 1;
     35     long_double_bits fb;
     36     fb.f = a;
     37     int e = (fb.u.high.s.low & 0x00007FFF) - 16383;
     38     if (e < 0)
     39         return 0;
     40     if ((unsigned)e >= sizeof(di_int) * CHAR_BIT)
     41         return a > 0 ? di_max : di_min;
     42     di_int s = -(si_int)((fb.u.high.s.low & 0x00008000) >> 15);
     43     di_int r = fb.u.low.all;
     44     r = (du_int)r >> (63 - e);
     45     return (r ^ s) - s;
     46 }
     47 
     48 #endif /* !_ARCH_PPC */
     49