StdLib/LibC/CRT/Ia32/llmul.c

/** @file
  64-bit Math Worker Function.
  The 32-bit versions of C compiler generate calls to library routines
  to handle 64-bit math. These functions use non-standard calling conventions.

  Copyright (c) 2009 - 2011, Intel Corporation. All rights reserved.<BR>
  This program and the accompanying materials are licensed and made available
  under the terms and conditions of the BSD License which accompanies this
  distribution.  The full text of the license may be found at
  http://opensource.org/licenses/bsd-license.php.

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

**/

#include <Library/BaseLib.h>

/*
 * Multiplies a 64-bit signed or unsigned value by a 64-bit signed or unsigned value
 * and returns a 64-bit result.
 */
__declspec(naked) void __cdecl _allmul (void)
{
  //
  // Wrapper Implementation over EDKII MultS64x64() routine
  //    INT64
  //    EFIAPI
  //    MultS64x64 (
  //      IN      INT64      Multiplicand,
  //      IN      INT64      Multiplier
  //      )
  //
  _asm {
    ; Original local stack when calling _allmul
    ;               -----------------
    ;               |               |
    ;               |---------------|
    ;               |               |
    ;               |--Multiplier --|
    ;               |               |
    ;               |---------------|
    ;               |               |
    ;               |--Multiplicand-|
    ;               |               |
    ;               |---------------|
    ;               |  ReturnAddr** |
    ;       ESP---->|---------------|
    ;

    ;
    ; Set up the local stack for Multiplicand parameter
    ;
    mov  eax, [esp + 16]
    push eax
    mov  eax, [esp + 16]
    push eax

    ;
    ; Set up the local stack for Multiplier parameter
    ;
    mov  eax, [esp + 16]
    push eax
    mov  eax, [esp + 16]
    push eax

    ;
    ; Call native MulS64x64 of BaseLib
    ;
    call MultS64x64

    ;
    ; Adjust stack
    ;
    add  esp, 16

    ret  16
  }
}