StdLib/LibC/CRT/Ia32/ulldvrm.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 result and the 64-bit signed remainder.
  23  */
  24 __declspec(naked) void __cdecl _aulldvrm(void)
  25 {
  26   //
  27   // Wrapper Implementation over EDKII DivU64x64Remainder() routine
  28   //    UINT64
  29   //    EFIAPI
  30   //    DivU64x64Remainder (
  31   //      IN      UINT64     Dividend,
  32   //      IN      UINT64     Divisor,
  33   //      OUT     UINT64     *Remainder
  34   //      )
  35   //
  36   _asm {
  37     ; Original local stack when calling _aulldvrm
  38     ;               -----------------
  39     ;               |               |
  40     ;               |---------------|
  41     ;               |               |
  42     ;               |--  Divisor  --|
  43     ;               |               |
  44     ;               |---------------|
  45     ;               |               |
  46     ;               |--  Dividend --|
  47     ;               |               |
  48     ;               |---------------|
  49     ;               |  ReturnAddr** |
  50     ;       ESP---->|---------------|
  51     ;
  52     ;
  53     ; On Exit:
  54     ;       EDX:EAX contains the quotient (dividend/divisor)
  55     ;       EBX:ECX contains the remainder (divided % divisor)
  56     ;       NOTE: this routine removes the parameters from the stack.
  57     ;
  58
  59     ;
  60     ; Set up the local stack for Remainder pointer
  61     ;
  62     sub  esp, 8
  63     push esp
  64
  65     ;
  66     ; Set up the local stack for Divisor parameter
  67     ;
  68     mov  eax, [esp + 28]
  69     push eax
  70     mov  eax, [esp + 28]
  71     push eax
  72
  73     ;
  74     ; Set up the local stack for Dividend parameter
  75     ;
  76     mov  eax, [esp + 28]
  77     push eax
  78     mov  eax, [esp + 28]
  79     push eax
  80
  81     ;
  82     ; Call native DivU64x64Remainder of BaseLib
  83     ;
  84     call DivU64x64Remainder
  85
  86     ;
  87     ; EDX:EAX contains the quotient (dividend/divisor)
  88     ; Put the Remainder in EBX:ECX
  89     ;
  90     mov  ecx, [esp + 20]
  91     mov  ebx, [esp + 24]
  92
  93     ;
  94     ; Adjust stack
  95     ;
  96     add  esp, 28
  97
  98     ret  16
  99   }
 100 }