arch/m68k-all/clib/setjmp.s

   1 /*
   2     Copyright © 1995-2007, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: setjmp
   6     Lang: english
   7 */
   8
   9 /******************************************************************************
  10
  11     NAME
  12 #include <setjmp.h>
  13
  14         int setjmp (jmp_buf env);
  15
  16     FUNCTION
  17         Save the current context so that you can return to it later.
  18
  19     INPUTS
  20         env - The context/environment is saved here for later restoring
  21
  22     RESULT
  23         0 if it returns from setjmp() and 1 when it returns from longjmp().
  24
  25     NOTES
  26
  27     EXAMPLE
  28         jmp_buf env;
  29
  30         ... some code ...
  31
  32         if (!setjmp (env))
  33         {
  34             ... this code is executed after setjmp() returns ...
  35
  36             // This is no good example on how to use this function
  37             // You should not do that
  38             if (error)
  39                 longjmp (env, 5);
  40
  41             ... some code ...
  42         }
  43         else
  44         {
  45             ... this code is executed if you call longjmp(env) ...
  46         }
  47
  48     BUGS
  49
  50     SEE ALSO
  51         longjmp()
  52
  53     INTERNALS
  54
  55     HISTORY
  56
  57 ******************************************************************************/
  58
  59         #include "aros/m68k/asm.h"
  60
  61         .text
  62         .balign 4
  63         .globl  setjmp
  64
  65         .set    FirstArg, 4 /* Skip Return-Adress */
  66         .set    env, FirstArg
  67         .set    retaddr, 0
  68
  69 setjmp:
  70         /* New version adapted from libnix instead of ixemul.
  71          * Note the slightly different register save order.
  72          */
  73         move.l  4(%sp),%a0              /* get address of jmp_buf */
  74         move.l  (%sp),(%a0)+            /* store return address */
  75         movem.l %d2-%d7/%a2-%a6/%sp,(%a0)       /* store all registers except scratch */
  76         moveq.l #0,%d0                  /* return 0 */
  77         rts
  78
  79 /*
  80         The jmp_buf is filled as follows (d0/d1/a0/a1 are not saved):
  81
  82         _jmp_buf        offset  contents
  83         [0]             0       old pc
  84         [1]             4       d2
  85         [2]             8       d3
  86         [3]             12      d4
  87         [4]             16      d5
  88         [5]             20      d6
  89         [6]             24      d7
  90         [7]             28      a2
  91         [8]             32      a3
  92         [9]             36      a4
  93         [10]            40      a5
  94         [11]            44      a6
  95         [12]            48      old sp
  96 */