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
  17
  18 /**
  19   Multiples a 64-bit unsigned integer by a 64-bit unsigned integer
  20   and generates a 64-bit unsigned result.
  21
  22   This function multiples the 64-bit unsigned value Multiplicand by the 64-bit
  23   unsigned value Multiplier and generates a 64-bit unsigned result. This 64-
  24   bit unsigned result is returned.
  25
  26   @param  Multiplicand  A 64-bit unsigned value.
  27   @param  Multiplier    A 64-bit unsigned value.
  28
  29   @return Multiplicand * Multiplier
  30
  31 **/
  32 UINT64
  33 EFIAPI
  34 InternalMathMultU64x64 (
  35   IN      UINT64                    Multiplicand,
  36   IN      UINT64                    Multiplier
  37   )
  38 {
  39   _asm {
  40     mov     ebx, dword ptr [Multiplicand + 0]
  41     mov     edx, dword ptr [Multiplier + 0]
  42     mov     ecx, ebx
  43     mov     eax, edx
  44     imul    ebx, dword ptr [Multiplier + 4]
  45     imul    edx, dword ptr [Multiplicand + 4]
  46     add     ebx, edx
  47     mul     ecx
  48     add     edx, ebx
  49   }
  50 }
  51