StdLib/LibC/CRT/Ia32/ulldiv.c

   1 /** @file
   2   64-bit Math Worker Function.
   3   The 32-bit versions of C compiler generate calls to library routines
   4   to handle 64-bit math. These functions use non-standard calling conventions.
   5
   6   Copyright (c) 2009 - 2011, Intel Corporation. All rights reserved.<BR>
   7   This program and the accompanying materials are licensed and made available
   8   under the terms and conditions of the BSD License which accompanies this
   9   distribution.  The full text of the license may be found at
  10   http://opensource.org/licenses/bsd-license.php.
  11
  12   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  13   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  14
  15 **/
  16
  17 #include <Library/BaseLib.h>
  18
  19
  20 /*
  21  * Divides a 64-bit unsigned value with a 64-bit unsigned value and returns
  22  * a 64-bit unsigned result.
  23  */
  24 __declspec(naked) void __cdecl _aulldiv (void)
  25 {
  26   //
  27   // Wrapper Implementation over EDKII DivU64x64Reminder() routine
  28   //    UINT64
  29   //    EFIAPI
  30   //    DivU64x64Remainder (
  31   //      IN      UINT64     Dividend,
  32   //      IN      UINT64     Divisor,
  33   //      OUT     UINT64     *Remainder  OPTIONAL
  34   //      )
  35   //
  36   _asm {
  37
  38     ; Original local stack when calling _aulldiv
  39     ;               -----------------
  40     ;               |               |
  41     ;               |---------------|
  42     ;               |               |
  43     ;               |--  Divisor  --|
  44     ;               |               |
  45     ;               |---------------|
  46     ;               |               |
  47     ;               |--  Dividend --|
  48     ;               |               |
  49     ;               |---------------|
  50     ;               |  ReturnAddr** |
  51     ;       ESP---->|---------------|
  52     ;
  53
  54     ;
  55     ; Set up the local stack for NULL Reminder pointer
  56     ;
  57     xor  eax, eax
  58     push eax
  59
  60     ;
  61     ; Set up the local stack for Divisor parameter
  62     ;
  63     mov  eax, [esp + 20]
  64     push eax
  65     mov  eax, [esp + 20]
  66     push eax
  67
  68     ;
  69     ; Set up the local stack for Dividend parameter
  70     ;
  71     mov  eax, [esp + 20]
  72     push eax
  73     mov  eax, [esp + 20]
  74     push eax
  75
  76     ;
  77     ; Call native DivU64x64Remainder of BaseLib
  78     ;
  79     call DivU64x64Remainder
  80
  81     ;
  82     ; Adjust stack
  83     ;
  84     add  esp, 20
  85
  86     ret  16
  87   }
  88 }