arch/i386-all/clib/longjmp.s

   1 /*
   2     Copyright © 1995-2011, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: ANSI C function longjmp()
   6     Lang: english
   7 */
   8
   9 /******************************************************************************
  10
  11     NAME
  12 #include <setjmp.h>
  13
  14         void longjmp (jmp_buf env, int val);
  15
  16     FUNCTION
  17         Save the current context so that you can return to it later.
  18
  19     INPUTS
  20         env - The context/environment to restore
  21         val - This value is returned by setjmp() when you return to the
  22                 saved context. You cannot return 0. If val is 0, then
  23                 setjmp() returns with 1.
  24
  25     RESULT
  26         This function doesn't return.
  27
  28     NOTES
  29
  30     EXAMPLE
  31         jmp_buf env;
  32
  33         ... some code ...
  34
  35         if (!setjmp (env))
  36         {
  37             ... this code is executed after setjmp() returns ...
  38
  39             // This is no good example on how to use this function
  40             // You should not do that
  41             if (error)
  42                 longjmp (env, 5);
  43
  44             ... some code ...
  45         }
  46         else
  47         {
  48             ... this code is executed if you call longjmp(env) ...
  49         }
  50
  51     BUGS
  52
  53     SEE ALSO
  54         setjmp()
  55
  56     INTERNALS
  57
  58     HISTORY
  59
  60 ******************************************************************************/
  61
  62         #include "aros/i386/asm.h"
  63
  64         .text
  65         _ALIGNMENT
  66         .globl  AROS_CDEFNAME(longjmp)
  67         _FUNCTION(AROS_CDEFNAME(longjmp))
  68
  69         .set    FirstArg, 4 /* Skip Return-Adress */
  70         .set    env, FirstArg
  71         .set    val, env+4
  72
  73 AROS_CDEFNAME(longjmp):
  74         /* Fetch the address of the env-structure off the stack.
  75             The address is stored in %eax which is not preserved
  76             because it's contents are overwritten anyway by the
  77             return code */
  78         movl env(%esp),%eax
  79
  80         /* Read return value into %ebx and make sure it's not 0 */
  81         movl val(%esp),%ebx
  82         cmpl $0,%ebx
  83         jne  1f
  84
  85         movl $1,%ebx
  86 1:
  87         /* Restore stack pointer and all registers from env */
  88         movl 28(%eax),%esp /* Restore original stack */
  89
  90         movl 0(%eax),%ecx
  91         movl %ecx,retaddr(%esp) /* Restore return address */
  92
  93         pushl %ebx /* Save return value on new stack */
  94
  95         /* Restore all registers */
  96         movl 4(%eax),%ebx /* %ebx */
  97         movl 8(%eax),%ecx /* %ecx */
  98         movl 12(%eax),%edx /* %edx */
  99         movl 16(%eax),%esi /* %esi */
 100         movl 20(%eax),%edi /* %edi */
 101         movl 24(%eax),%ebp /* %ebp */
 102
 103         popl %eax /* Fetch return value */
 104         ret