StdLib/LibC/CRT/Ia32/lldiv.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 with a 64-bit signed value and returns
  22  * a 64-bit signed result.
  23  */
  24 __declspec(naked) void __cdecl _alldiv (void)
  25 {
  26   //
  27   // Wrapper Implementation over EDKII DivS64x64Remainder() routine
  28   //    INT64
  29   //    EFIAPI
  30   //    DivS64x64Remainder (
  31   //      IN      UINT64     Dividend,
  32   //      IN      UINT64     Divisor,
  33   //      OUT     UINT64     *Remainder  OPTIONAL
  34   //      )
  35   //
  36   _asm {
  37
  38     ;Entry:
  39     ;       Arguments are passed on the stack:
  40     ;               1st pushed: divisor (QWORD)
  41     ;               2nd pushed: dividend (QWORD)
  42     ;
  43     ;Exit:
  44     ;       EDX:EAX contains the quotient (dividend/divisor)
  45     ;       NOTE: this routine removes the parameters from the stack.
  46     ;
  47     ; Original local stack when calling _alldiv
  48     ;               -----------------
  49     ;               |               |
  50     ;               |---------------|
  51     ;               |               |
  52     ;               |--  Divisor  --|
  53     ;               |               |
  54     ;               |---------------|
  55     ;               |               |
  56     ;               |--  Dividend --|
  57     ;               |               |
  58     ;               |---------------|
  59     ;               |  ReturnAddr** |
  60     ;       ESP---->|---------------|
  61     ;
  62
  63     ;
  64     ; Set up the local stack for NULL Reminder pointer
  65     ;
  66     xor  eax, eax
  67     push eax
  68
  69     ;
  70     ; Set up the local stack for Divisor parameter
  71     ;
  72     mov  eax, [esp + 20]
  73     push eax
  74     mov  eax, [esp + 20]
  75     push eax
  76
  77     ;
  78     ; Set up the local stack for Dividend parameter
  79     ;
  80     mov  eax, [esp + 20]
  81     push eax
  82     mov  eax, [esp + 20]
  83     push eax
  84
  85     ;
  86     ; Call native DivS64x64Remainder of BaseLib
  87     ;
  88     call DivS64x64Remainder
  89
  90     ;
  91     ; Adjust stack
  92     ;
  93     add  esp, 20
  94
  95     ret  16
  96   }
  97 }