arch/.unmaintained/m68k-emul/clib/longjmp.s

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: 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 "machine.i"
  63
  64 #define FirstArg        4 /* Skip Return-Adress */
  65 #define env             FirstArg
  66 #define val             FirstArg+4
  67
  68         .text
  69         .balign 16
  70         .globl  AROS_CDEFNAME(longjmp)
  71         .type   AROS_CDEFNAME(longjmp),@function
  72 AROS_CDEFNAME(longjmp):
  73         move.l  env(%sp),%a0            /* save area pointer */
  74         move.l  val(%sp),%d0
  75         jbne    .okret
  76         moveq.l #1,%d0                  /* make sure it isn't 0 */
  77 .okret:
  78         move.l  4(%a0),%sp              /* restore SP */
  79         move.l  0(%a0),(%sp)            /* restore PC */
  80         movem.l 8(%a0),%d2-%d7/%a2-%a6  /* restore remaining non-scratch regs */
  81         rts
  82
  83 /*
  84         The jmp_buf is filled as follows (d0/d1/a0/a1 are not saved):
  85
  86         _jmp_buf        offset  contents
  87         [0]             0       old pc
  88         [1]             4       old sp
  89         [2]             8       d2
  90         [3]             12      d3
  91         [4]             16      d4
  92         [5]             20      d5
  93         [6]             24      d6
  94         [7]             28      d7
  95         [8]             32      a2
  96         [9]             36      a3
  97         [10]            40      a4
  98         [11]            44      a5
  99         [12]            48      a6
 100 */