arch/.unmaintained/m68k-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 "machine.i"
  60
  61         .text
  62         .balign 4
  63         .globl  AROS_CDEFNAME(setjmp)
  64         .type   AROS_CDEFNAME(setjmp),@function
  65
  66         .set    FirstArg, 4 /* Skip Return-Adress */
  67         .set    env, FirstArg
  68         .set    retaddr, 0
  69
  70 AROS_CDEFNAME(setjmp):
  71 #if OLDJMP
  72         move.l  env(sp),a0              /* save area pointer */
  73         move.l  retaddr(sp),(a0)+       /* save old PC (return address) */
  74         lea     env(sp),a1              /* adjust saved SP since we won't rts */
  75         move.l  a1,(a0)+                /* save old SP */
  76         movem.l d2-d7/a2-a6,(a0)        /* save remaining non-scratch regs */
  77         clr.l   d0                      /* return 0 */
  78         rts
  79 #else
  80         /* New version adapted from libnix instead of ixemul.
  81          * Note the slightly different register save order.
  82          */
  83         move.l  4(sp),a0                /* get address of jmp_buf */
  84         move.l  (sp),(a0)+              /* store return address */
  85         movem.l d2-d7/a2-a6/sp,(a0)     /* store all registers except scratch */
  86         moveq.l #0,d0                   /* return 0 */
  87         rts
  88 #endif
  89
  90 /*
  91         The jmp_buf is filled as follows (d0/d1/a0/a1 are not saved):
  92
  93         _jmp_buf        offset  contents
  94         [0]             0       old pc
  95         [1]             4       d2
  96         [2]             8       d3
  97         [3]             12      d4
  98         [4]             16      d5
  99         [5]             20      d6
 100         [6]             24      d7
 101         [7]             28      a2
 102         [8]             32      a3
 103         [9]             36      a4
 104         [10]            40      a5
 105         [11]            44      a6
 106         [12]            48      old sp
 107 */