MdePkg/Library/BaseLib/Ia32/MultU64x64.c

   1 /** @file
   2   Calculate the product of a 64-bit integer and another 64-bit integer
   3
   4   Copyright (c) 2006 - 2007, Intel Corporation<BR>
   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 //
  16 // Include common header file for this module.
  17 //
  18
  19
  20 /**
  21   Multiples a 64-bit unsigned integer by a 64-bit unsigned integer
  22   and generates a 64-bit unsigned result.
  23
  24   This function multiples the 64-bit unsigned value Multiplicand by the 64-bit
  25   unsigned value Multiplier and generates a 64-bit unsigned result. This 64-
  26   bit unsigned result is returned.
  27
  28   @param  Multiplicand  A 64-bit unsigned value.
  29   @param  Multiplier    A 64-bit unsigned value.
  30
  31   @return Multiplicand * Multiplier
  32
  33 **/
  34 UINT64
  35 EFIAPI
  36 InternalMathMultU64x64 (
  37   IN      UINT64                    Multiplicand,
  38   IN      UINT64                    Multiplier
  39   )
  40 {
  41   _asm {
  42     mov     ebx, dword ptr [Multiplicand + 0]
  43     mov     edx, dword ptr [Multiplier + 0]
  44     mov     ecx, ebx
  45     mov     eax, edx
  46     imul    ebx, dword ptr [Multiplier + 4]
  47     imul    edx, dword ptr [Multiplicand + 4]
  48     add     ebx, edx
  49     mul     ecx
  50     add     edx, ebx
  51   }
  52 }
  53