sysdeps/vax/__longjmp.c

   1 /* Copyright (C) 1991, 1992, 1994, 1997 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.
  18
  19    Derived from @(#)_setjmp.s   5.7 (Berkeley) 6/27/88,
  20    Copyright (C) 1980 Regents of the University of California.
  21    All rights reserved.
  22
  23    Redistribution and use in source and binary forms, with or without
  24    modification, are permitted provided that the following conditions
  25    are met:
  26
  27    1. Redistributions of source code must retain the above copyright
  28       notice, this list of conditions and the following disclaimer.
  29    2. Redistributions in binary form must reproduce the above copyright
  30       notice, this list of conditions and the following disclaimer in the
  31       documentation and/or other materials provided with the distribution.
  32    4. Neither the name of the University nor the names of its contributors
  33       may be used to endorse or promote products derived from this software
  34       without specific prior written permission.
  35
  36    THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  37    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  38    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  39    ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  40    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  41    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  42    OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  43    HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  44    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  45    OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  46    SUCH DAMAGE.*/
  47
  48 #include <setjmp.h>
  49
  50 #ifndef __GNUC__
  51   #error This file uses GNU C extensions; you must compile with GCC.
  52 #endif
  53
  54
  55 #define REI     02      /* Vax `rei' opcode.  */
  56
  57 /* Jump to the position specified by ENV, causing the
  58    setjmp call there to return VAL, or 1 if VAL is 0.  */
  59 __NORETURN
  60 void
  61 __longjmp (env, val)
  62      const __jmp_buf env;
  63      int val;
  64 {
  65   register long int *fp asm("fp");
  66   long int *regsave;
  67   unsigned long int flags;
  68
  69   if (env.__fp == NULL)
  70     __libc_fatal("longjmp: Invalid ENV argument.\n");
  71
  72   if (val == 0)
  73     val = 1;
  74
  75   asm volatile("loop:");
  76
  77   flags = *(long int *) (6 + (char *) fp);
  78   regsave = (long int *) (20 + (char *) fp);
  79   if (flags & 1)
  80     /* R0 was saved by the caller.
  81        Store VAL where it will be restored from.  */
  82     *regsave++ = val;
  83   if (flags & 2)
  84     /* R1 was saved by the caller.
  85        Store ENV where it will be restored from.  */
  86     *regsave = env;
  87
  88   /* Was the FP saved in the last call the same one in ENV?  */
  89   asm volatile("cmpl %0, 12(fp);"
  90                /* Yes, return to it.  */
  91                "beql done;"
  92                /* The FP in ENV is less than the one saved in the last call.
  93                   This means we have already returned from the function that
  94                   called `setjmp' with ENV!  */
  95                "blssu latejump;" : /* No outputs.  */ : "g" (env.__fp));
  96
  97   /* We are more than one level below the state in ENV.
  98      Return to where we will pop another stack frame.  */
  99   asm volatile("movl $loop, 16(fp);"
 100                "ret");
 101
 102   asm volatile("done:");
 103   {
 104     char return_insn asm("*16(fp)");
 105     if (return_insn == REI)
 106       /* We're returning with an `rei' instruction.
 107          Do a return with PSL-PC pop.  */
 108       asm volatile("movab 0f, 16(fp)");
 109     else
 110       /* Do a standard return.  */
 111       asm volatile("movab 1f, 16(fp)");
 112
 113     /* Return.  */
 114     asm volatile("ret");
 115   }
 116
 117   asm volatile("0:"     /* `rei' return.  */
 118                /* Compensate for PSL-PC push.  */
 119                "addl2 %0, sp;"
 120                "1:"     /* Standard return.  */
 121                /* Return to saved PC.  */
 122                "jmp %1" : /* No outputs.  */ :
 123                "g" (8), "g" (env.__pc));
 124
 125   /* Jump here when the FP saved in ENV points
 126      to a function that has already returned.  */
 127   asm volatile("latejump:");
 128   __libc_fatal("longjmp: Attempt to jump to a function that has returned.\n");
 129 }