bertos/emul/switch_i386.S

   1 /*!
   2  * \file
   3  * <!--
   4  * Copyright 2004 Develer S.r.l. (http://www.develer.com/)
   5  * Copyright 1999,2000,2001 Bernardo Innocenti <bernie@develer.com>
   6  * This file is part of DevLib - See devlib/README for information.
   7  * -->
   8  *
   9  * \brief i386 context switch
  10  *
  11  * \version $Id$
  12  *
  13  * \author Bernardo Innocenti <bernie@develer.com>
  14  */
  15
  16
  17
  18 #ifdef __APPLE__
  19     //This workaround is necessary to compile under OS X assembler.
  20     #define SWITCH_CONTEXT _asm_switch_context
  21     #define SWITCH_VERSION _asm_switch_version
  22 #else
  23     #define SWITCH_CONTEXT asm_switch_context
  24     #define SWITCH_VERSION asm_switch_version
  25 #endif
  26
  27 /* void asm_switch_context(void ** new_sp, void ** save_sp) */
  28 .globl SWITCH_CONTEXT
  29 SWITCH_CONTEXT:
  30         pushl   %eax
  31         pushl   %ebx
  32         pushl   %ecx
  33         pushl   %edx
  34         pushl   %esi
  35         pushl   %edi
  36         pushl   %ebp
  37         movl    0x24(%esp),%ebp         /* ebp = save_sp */
  38         movl    %esp,(%ebp)             /* *save_sp = esp */
  39         movl    0x20(%esp),%ebp         /* ebp = new_sp */
  40         movl    (%ebp),%esp             /* esp = *new_sp */
  41         popl    %ebp
  42         popl    %edi
  43         popl    %esi
  44         popl    %edx
  45         popl    %ecx
  46         popl    %ebx
  47         popl    %eax
  48         ret
  49
  50 /* int asm_switch_version(void) */
  51 .globl SWITCH_VERSION
  52 SWITCH_VERSION:
  53         mov     $1,%eax
  54         ret
  55