MdePkg/Library/BaseLib/Ia32/MultU64x32.c

   1 /** @file
   2   Calculate the product of a 64-bit integer and a 32-bit integer
   3
   4   Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
   5   SPDX-License-Identifier: BSD-2-Clause-Patent
   6
   7 **/
   8
   9 /**
  10   Multiples a 64-bit unsigned integer by a 32-bit unsigned integer
  11   and generates a 64-bit unsigned result.
  12
  13   This function multiples the 64-bit unsigned value Multiplicand by the 32-bit
  14   unsigned value Multiplier and generates a 64-bit unsigned result. This 64-
  15   bit unsigned result is returned.
  16
  17   @param  Multiplicand  A 64-bit unsigned value.
  18   @param  Multiplier    A 32-bit unsigned value.
  19
  20   @return Multiplicand * Multiplier
  21
  22 **/
  23 UINT64
  24 EFIAPI
  25 InternalMathMultU64x32 (
  26   IN      UINT64  Multiplicand,
  27   IN      UINT32  Multiplier
  28   )
  29 {
  30   _asm {
  31     mov     ecx, Multiplier
  32     mov     eax, ecx
  33     imul    ecx, dword ptr [Multiplicand + 4]  // overflow not detectable
  34     mul     dword ptr [Multiplicand + 0]
  35     add     edx, ecx
  36   }
  37 }