lib/builtins/fixunssfdi.c

   1 /* ===-- fixunssfdi.c - Implement __fixunssfdi -----------------------------===
   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 __fixunssfdi for the compiler_rt library.
  11  *
  12  * ===----------------------------------------------------------------------===
  13  */
  14
  15 #include "int_lib.h"
  16 /* Returns: convert a to a unsigned long long, rounding toward zero.
  17  *          Negative values all become zero.
  18  */
  19
  20 /* Assumption: float is a IEEE 32 bit floating point type
  21  *             du_int is a 64 bit integral type
  22  *             value in float is representable in du_int or is negative
  23  *                 (no range checking performed)
  24  */
  25
  26 /* seee eeee emmm mmmm mmmm mmmm mmmm mmmm */
  27
  28 ARM_EABI_FNALIAS(f2ulz, fixunssfdi)
  29
  30 COMPILER_RT_ABI du_int
  31 __fixunssfdi(float a)
  32 {
  33     float_bits fb;
  34     fb.f = a;
  35     int e = ((fb.u & 0x7F800000) >> 23) - 127;
  36     if (e < 0 || (fb.u & 0x80000000))
  37         return 0;
  38     du_int r = (fb.u & 0x007FFFFF) | 0x00800000;
  39     if (e > 23)
  40         r <<= (e - 23);
  41     else
  42         r >>= (23 - e);
  43     return r;
  44 }