ArmPkg/Library/CompilerIntrinsicsLib/Arm/divsi3.c

   1 /** @file
   2   Compiler intrinsic for 32--bit unsigned division, ported from LLVM code.
   3
   4
   5   Copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
   6
   7   SPDX-License-Identifier: BSD-2-Clause-Patent
   8
   9 **/
  10 /**
  11   University of Illinois/NCSA
  12   Open Source License
  13
  14   Copyright (c) 2003-2008 University of Illinois at Urbana-Champaign.
  15   All rights reserved.
  16
  17   Developed by:
  18
  19       LLVM Team
  20
  21       University of Illinois at Urbana-Champaign
  22
  23       http://llvm.org
  24
  25   Permission is hereby granted, free of charge, to any person obtaining a copy of
  26   this software and associated documentation files (the "Software"), to deal with
  27   the Software without restriction, including without limitation the rights to
  28   use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
  29   of the Software, and to permit persons to whom the Software is furnished to do
  30   so, subject to the following conditions:
  31
  32       * Redistributions of source code must retain the above copyright notice,
  33         this list of conditions and the following disclaimers.
  34
  35       * Redistributions in binary form must reproduce the above copyright notice,
  36         this list of conditions and the following disclaimers in the
  37         documentation and/or other materials provided with the distribution.
  38
  39       * Neither the names of the LLVM Team, University of Illinois at
  40         Urbana-Champaign, nor the names of its contributors may be used to
  41         endorse or promote products derived from this Software without specific
  42         prior written permission.
  43
  44   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  45   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
  46   FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
  47   CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  48   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  49   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
  50   SOFTWARE.
  51 **/
  52
  53
  54 #include "Llvm_int_lib.h"
  55
  56 UINT32 __udivsi3(UINT32 n, UINT32 d);
  57
  58 // Returns: a / b
  59
  60 INT32
  61 __divsi3(INT32 a, INT32 b)
  62 {
  63     const int bits_in_word_m1 = (int)(sizeof(INT32) * CHAR_BIT) - 1;
  64     INT32 s_a = a >> bits_in_word_m1;           // s_a = a < 0 ? -1 : 0
  65     INT32 s_b = b >> bits_in_word_m1;           // s_b = b < 0 ? -1 : 0
  66     a = (a ^ s_a) - s_a;                         // negate if s_a == -1
  67     b = (b ^ s_b) - s_b;                         // negate if s_b == -1
  68     s_a ^= s_b;                                  // sign of quotient
  69     return (__udivsi3(a, b) ^ s_a) - s_a;        // negate if s_a == -1
  70 }
  71
  72