arch/.unmaintained/m68k-pp-native/clib/setjmp.s

   1 /*
   2     Copyright © 1995-2001, 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 "../include/aros/machine.i"
  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 #if OLDJMP
  71         move.l  env(%sp),%a0            /* save area pointer */
  72         move.l  retaddr(%sp),(%a0)+     /* save old PC (return address) */
  73         lea     env(%sp),%a1            /* adjust saved SP since we won't rts */
  74         move.l  %a1,(%a0)+              /* save old SP */
  75         movem.l %d2-%d7/%a2-%a6,(%a0)   /* save remaining non-scratch regs */
  76         clr.l   %d0                     /* return 0 */
  77         rts
  78 #else
  79         /* New version adapted from libnix instead of ixemul.
  80          * Note the slightly different register save order.
  81          */
  82         move.l  4(%sp),%a0              /* get address of jmp_buf */
  83         move.l  (%sp),(%a0)+            /* store return address */
  84         movem.l %d2-%d7/%a2-%a6/%sp,(%a0)       /* store all registers except scratch */
  85         moveq.l #0,%d0                  /* return 0 */
  86         rts
  87 #endif
  88
  89 /*
  90         The jmp_buf is filled as follows (d0/d1/a0/a1 are not saved):
  91
  92         _jmp_buf        offset  contents
  93         [0]             0       old pc
  94         [1]             4       d2
  95         [2]             8       d3
  96         [3]             12      d4
  97         [4]             16      d5
  98         [5]             20      d6
  99         [6]             24      d7
 100         [7]             28      a2
 101         [8]             32      a3
 102         [9]             36      a4
 103         [10]            40      a5
 104         [11]            44      a6
 105         [12]            48      old sp
 106 */