arch/.unmaintained/m68k-native/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         .text
  65         .balign 4
  66         .globl  AROS_CDEFNAME(longjmp)
  67         .type   AROS_CDEFNAME(longjmp),@function
  68
  69         .set    FirstArg, 4 /* Skip Return-Adress */
  70         .set    env, FirstArg
  71         .set    val, env+4
  72         .set    retaddr, 0
  73 AROS_CDEFNAME(longjmp):
  74 #ifdef OLDJMP
  75         move.l  env(sp),a0              /* save area pointer */
  76         move.l  val(sp),d0
  77         jne     okret
  78         moveq.l #1,d0                   /* make sure it isn't 0 */
  79 okret:
  80         move.l  4(a0),sp                /* restore SP */
  81         move.l  0(a0),(sp)              /* restore PC */
  82         movem.l 8(a0),d2-d7/a2-a6       /* restore remaining non-scratch regs */
  83         rts
  84 #else
  85         /* New version adapted from libnix instead of ixemul.
  86          * Note the slightly different register save order.
  87          */
  88         addq.w  #4,sp                   /* returns to other address */
  89         move.l  (sp)+,a0                /* get address of jmp_buf */
  90         move.l  (sp)+,d0                /* get return code */
  91         jne     .okret
  92         moveq.l #1,d0                   /* make sure it isn't 0 */
  93 .okret:
  94         move.l  48(a0),sp               /* restore sp */
  95         move.l  (a0)+,(sp)              /* set return address */
  96         movem.l (a0),d2-d7/a2-a6        /* restore all registers except scratch and sp */
  97         rts
  98 #endif
  99
 100 /*
 101         The jmp_buf is filled as follows (d0/d1/a0/a1 are not saved):
 102
 103         _jmp_buf        offset  contents
 104         [0]             0       old pc
 105         [1]             4       d2
 106         [2]             8       d3
 107         [3]             12      d4
 108         [4]             16      d5
 109         [5]             20      d6
 110         [6]             24      d7
 111         [7]             28      a2
 112         [8]             32      a3
 113         [9]             36      a4
 114         [10]            40      a5
 115         [11]            44      a6
 116         [12]            48      old sp
 117 */