audk/ArmPkg/Library/CompilerIntrinsicsLib/Arm/muldi3.c

/** @file

  Copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
  
  This program and the accompanying materials
  are licensed and made available under the terms and conditions of the BSD License
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  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

**/
/**
  University of Illinois/NCSA
  Open Source License
  
  Copyright (c) 2003-2008 University of Illinois at Urbana-Champaign.
  All rights reserved.
  
  Developed by:
  
      LLVM Team
  
      University of Illinois at Urbana-Champaign
  
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**/

#include <Base.h>
#include "Llvm_int_lib.h"


// Returns: a * b

static
INT64
__muldsi3(UINT32 a, UINT32 b)
{
    dwords r;
    const int bits_in_word_2 = (int)(sizeof(INT32) * CHAR_BIT) / 2;
    const UINT32 lower_mask = (UINT32)~0 >> bits_in_word_2;
    r.low = (a & lower_mask) * (b & lower_mask);
    UINT32 t = r.low >> bits_in_word_2;
    r.low &= lower_mask;
    t += (a >> bits_in_word_2) * (b & lower_mask);
    r.low += (t & lower_mask) << bits_in_word_2;
    r.high = t >> bits_in_word_2;
    t = r.low >> bits_in_word_2;
    r.low &= lower_mask;
    t += (b >> bits_in_word_2) * (a & lower_mask);
    r.low += (t & lower_mask) << bits_in_word_2;
    r.high += t >> bits_in_word_2;
    r.high += (a >> bits_in_word_2) * (b >> bits_in_word_2);
    return r.all;
}

// Returns: a * b

INT64
__muldi3(INT64 a, INT64 b)
{
    dwords x;
    x.all = a;
    dwords y;
    y.all = b;
    dwords r;
    r.all = __muldsi3(x.low, y.low);
    r.high += x.high * y.low + x.low * y.high;
    return r.all;
}