ArmPkg/Library/CompilerIntrinsicsLib/Arm/ashldi3.c

   1 /** @file
   2
   3   Copyright (c) 2008-2009, Apple Inc. All rights reserved.
   4
   5   All rights reserved. This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14 /**
  15   University of Illinois/NCSA
  16   Open Source License
  17
  18   Copyright (c) 2003-2008 University of Illinois at Urbana-Champaign.
  19   All rights reserved.
  20
  21   Developed by:
  22
  23       LLVM Team
  24
  25       University of Illinois at Urbana-Champaign
  26
  27       http://llvm.org
  28
  29   Permission is hereby granted, free of charge, to any person obtaining a copy of
  30   this software and associated documentation files (the "Software"), to deal with
  31   the Software without restriction, including without limitation the rights to
  32   use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
  33   of the Software, and to permit persons to whom the Software is furnished to do
  34   so, subject to the following conditions:
  35
  36       * Redistributions of source code must retain the above copyright notice,
  37         this list of conditions and the following disclaimers.
  38
  39       * Redistributions in binary form must reproduce the above copyright notice,
  40         this list of conditions and the following disclaimers in the
  41         documentation and/or other materials provided with the distribution.
  42
  43       * Neither the names of the LLVM Team, University of Illinois at
  44         Urbana-Champaign, nor the names of its contributors may be used to
  45         endorse or promote products derived from this Software without specific
  46         prior written permission.
  47
  48   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  49   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
  50   FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
  51   CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  52   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  53   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
  54   SOFTWARE.
  55 **/
  56
  57 #include "Llvm_int_lib.h"
  58
  59 // Returns: a << b
  60
  61 // Precondition:  0 <= b < bits_in_dword
  62
  63 INT64
  64 __ashldi3(INT64 a, INT32 b)
  65 {
  66     const int bits_in_word = (int)(sizeof(INT32) * CHAR_BIT);
  67     dwords input;
  68     dwords result;
  69     input.all = a;
  70     if (b & bits_in_word)  // bits_in_word <= b < bits_in_dword
  71     {
  72         result.low = 0;
  73         result.high = input.low << (b - bits_in_word);
  74     }
  75     else  // 0 <= b < bits_in_word
  76     {
  77         if (b == 0)
  78             return a;
  79         result.low  = input.low << b;
  80         result.high = (input.high << b) | (input.low >> (bits_in_word - b));
  81     }
  82     return result.all;
  83 }