MdePkg/Library/BaseLib/Ia32/DivU64x32.c

   1 /** @file
   2   Calculate the quotient of a 64-bit integer by a 32-bit integer
   3
   4   Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
   5   SPDX-License-Identifier: BSD-2-Clause-Patent
   6
   7 **/
   8
   9
  10
  11
  12 /**
  13   Divides a 64-bit unsigned integer by a 32-bit unsigned integer and
  14   generates a 64-bit unsigned result.
  15
  16   This function divides the 64-bit unsigned value Dividend by the 32-bit
  17   unsigned value Divisor and generates a 64-bit unsigned quotient. This
  18   function returns the 64-bit unsigned quotient.
  19
  20   @param  Dividend  A 64-bit unsigned value.
  21   @param  Divisor   A 32-bit unsigned value.
  22
  23   @return Dividend / Divisor
  24
  25 **/
  26 UINT64
  27 EFIAPI
  28 InternalMathDivU64x32 (
  29   IN      UINT64                    Dividend,
  30   IN      UINT32                    Divisor
  31   )
  32 {
  33   _asm {
  34     mov     eax, dword ptr [Dividend + 4]
  35     mov     ecx, Divisor
  36     xor     edx, edx
  37     div     ecx
  38     push    eax                     ; save quotient on stack
  39     mov     eax, dword ptr [Dividend]
  40     div     ecx
  41     pop     edx                     ; restore high-order dword of the quotient
  42   }
  43 }
  44