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      1 /* ===-- fixdfdi.c - Implement __fixdfdi -----------------------------------===
      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 __fixdfdi for the compiler_rt library.
     11  *
     12  * ===----------------------------------------------------------------------===
     13  */
     14 
     15 #include "int_lib.h"
     16 
     17 /* Returns: convert a to a signed long long, rounding toward zero. */
     18 
     19 /* Assumption: double is a IEEE 64 bit floating point type
     20  *            su_int is a 32 bit integral type
     21  *            value in double is representable in di_int (no range checking performed)
     22  */
     23 
     24 /* seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm */
     25 
     26 ARM_EABI_FNALIAS(d2lz, fixdfdi)
     27 
     28 COMPILER_RT_ABI di_int
     29 __fixdfdi(double a)
     30 {
     31     double_bits fb;
     32     fb.f = a;
     33     int e = ((fb.u.s.high & 0x7FF00000) >> 20) - 1023;
     34     if (e < 0)
     35         return 0;
     36     di_int s = (si_int)(fb.u.s.high & 0x80000000) >> 31;
     37     dwords r;
     38     r.s.high = (fb.u.s.high & 0x000FFFFF) | 0x00100000;
     39     r.s.low = fb.u.s.low;
     40     if (e > 52)
     41         r.all <<= (e - 52);
     42     else
     43         r.all >>= (52 - e);
     44     return (r.all ^ s) - s;
     45 }
     46