arch/.unmaintained/m68k-emul/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 #define FirstArg        4 /* Skip Return-Address */
  62 #define env             FirstArg
  63 #define retaddr         0
  64
  65         .text
  66         .balign 16
  67         .globl  AROS_CDEFNAME(setjmp)
  68         .type   AROS_CDEFNAME(setjmp),@function
  69 AROS_CDEFNAME(setjmp):
  70         move.l  env(%sp),%a0            /* save area pointer */
  71         move.l  retaddr(%sp),(%a0)+     /* save old PC */
  72         lea.l   env(%sp),%a1            /* adjust saved SP since we won't rts */
  73         move.l  %a1,(%a0)+              /* save old SP */
  74         movem.l %d2-%d7/%a2-%a6,(%a0)   /* save remaining non-scratch regs */
  75         clr.l   %d0                     /* return 0 */
  76         rts
  77
  78 /*
  79         The jmp_buf is filled as follows (d0/d1/a0/a1 are not saved):
  80
  81         _jmp_buf        offset  contents
  82         [0]             0       old pc
  83         [1]             4       old sp
  84         [2]             8       d2
  85         [3]             12      d3
  86         [4]             16      d4
  87         [5]             20      d5
  88         [6]             24      d6
  89         [7]             28      d7
  90         [8]             32      a2
  91         [9]             36      a3
  92         [10]            40      a4
  93         [11]            44      a5
  94         [12]            48      a6
  95 */