StdLib/LibC/CRT/Ia32/llrem.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 signed value by another 64-bit signed value and returns
  22  * the 64-bit signed remainder.
  23  */
  24 __declspec(naked) void __cdecl _allrem(void)
  25 {
  26   //
  27   // Wrapper Implementation over EDKII DivS64x64Remainder() routine
  28   //    UINT64
  29   //    EFIAPI
  30   //    DivS64x64Remainder (
  31   //      IN      UINT64     Dividend,
  32   //      IN      UINT64     Divisor,
  33   //      OUT     UINT64     *Remainder
  34   //      )
  35   //
  36   _asm {
  37     ; Original local stack when calling _allrem
  38     ;               -----------------
  39     ;               |               |
  40     ;               |---------------|
  41     ;               |               |
  42     ;               |--  Divisor  --|
  43     ;               |               |
  44     ;               |---------------|
  45     ;               |               |
  46     ;               |--  Dividend --|
  47     ;               |               |
  48     ;               |---------------|
  49     ;               |  ReturnAddr** |
  50     ;       ESP---->|---------------|
  51     ;
  52
  53     ;
  54     ; Set up the local stack for Reminder pointer
  55     ;
  56     sub  esp, 8
  57     push esp
  58
  59     ;
  60     ; Set up the local stack for Divisor parameter
  61     ;
  62     mov  eax, [esp + 28]
  63     push eax
  64     mov  eax, [esp + 28]
  65     push eax
  66
  67     ;
  68     ; Set up the local stack for Dividend parameter
  69     ;
  70     mov  eax, [esp + 28]
  71     push eax
  72     mov  eax, [esp + 28]
  73     push eax
  74
  75     ;
  76     ; Call native DivS64x64Remainder of BaseLib
  77     ;
  78     call DivS64x64Remainder
  79
  80     ;
  81     ; Put the Reminder in EDX:EAX as return value
  82     ;
  83     mov  eax, [esp + 20]
  84     mov  edx, [esp + 24]
  85
  86     ;
  87     ; Adjust stack
  88     ;
  89     add  esp, 28
  90
  91     ret  16
  92   }
  93 }