lib/builtins/fixunssfsi.c

   1 /* ===-- fixunssfsi.c - Implement __fixunssfsi -----------------------------===
   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 __fixunssfsi for the compiler_rt library.
  11  *
  12  * ===----------------------------------------------------------------------===
  13  */
  14
  15 #include "int_lib.h"
  16
  17 /* Returns: convert a to a unsigned int, rounding toward zero.
  18  *          Negative values all become zero.
  19  */
  20
  21 /* Assumption: float is a IEEE 32 bit floating point type
  22  *             su_int is a 32 bit integral type
  23  *             value in float is representable in su_int or is negative
  24  *                 (no range checking performed)
  25  */
  26
  27 /* seee eeee emmm mmmm mmmm mmmm mmmm mmmm */
  28
  29 ARM_EABI_FNALIAS(f2uiz, fixunssfsi)
  30
  31 COMPILER_RT_ABI su_int
  32 __fixunssfsi(float a)
  33 {
  34     float_bits fb;
  35     fb.f = a;
  36     int e = ((fb.u & 0x7F800000) >> 23) - 127;
  37     if (e < 0 || (fb.u & 0x80000000))
  38         return 0;
  39     su_int r = (fb.u & 0x007FFFFF) | 0x00800000;
  40     if (e > 23)
  41         r <<= (e - 23);
  42     else
  43         r >>= (23 - e);
  44     return r;
  45 }