glibc/sysdeps/vax/__longjmp.c

/* Copyright (C) 1991, 1992, 1994, 1997 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
 
   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  

   Derived from @(#)_setjmp.s	5.7 (Berkeley) 6/27/88,
   Copyright (C) 1980 Regents of the University of California.
   All rights reserved.

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:

   1. Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
   2. Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
   4. Neither the name of the University nor the names of its contributors
      may be used to endorse or promote products derived from this software
      without specific prior written permission.
   
   THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   SUCH DAMAGE.*/

#include <setjmp.h>

#ifndef	__GNUC__
  #error This file uses GNU C extensions; you must compile with GCC.
#endif


#define	REI	02	/* Vax `rei' opcode.  */

/* Jump to the position specified by ENV, causing the
   setjmp call there to return VAL, or 1 if VAL is 0.  */
__NORETURN
void
__longjmp (env, val)
     const __jmp_buf env;
     int val;
{
  register long int *fp asm("fp");
  long int *regsave;
  unsigned long int flags;

  if (env.__fp == NULL)
    __libc_fatal("longjmp: Invalid ENV argument.\n");

  if (val == 0)
    val = 1;

  asm volatile("loop:");

  flags = *(long int *) (6 + (char *) fp);
  regsave = (long int *) (20 + (char *) fp);
  if (flags & 1)
    /* R0 was saved by the caller.
       Store VAL where it will be restored from.  */
    *regsave++ = val;
  if (flags & 2)
    /* R1 was saved by the caller.
       Store ENV where it will be restored from.  */
    *regsave = env;

  /* Was the FP saved in the last call the same one in ENV?  */
  asm volatile("cmpl %0, 12(fp);"
	       /* Yes, return to it.  */
	       "beql done;"
	       /* The FP in ENV is less than the one saved in the last call.
		  This means we have already returned from the function that
		  called `setjmp' with ENV!  */
	       "blssu latejump;" : /* No outputs.  */ : "g" (env.__fp));

  /* We are more than one level below the state in ENV.
     Return to where we will pop another stack frame.  */
  asm volatile("movl $loop, 16(fp);"
	       "ret");

  asm volatile("done:");
  {
    char return_insn asm("*16(fp)");
    if (return_insn == REI)
      /* We're returning with an `rei' instruction.
	 Do a return with PSL-PC pop.  */
      asm volatile("movab 0f, 16(fp)");
    else
      /* Do a standard return.  */
      asm volatile("movab 1f, 16(fp)");

    /* Return.  */
    asm volatile("ret");
  }

  asm volatile("0:"	/* `rei' return.  */
	       /* Compensate for PSL-PC push.  */
	       "addl2 %0, sp;"
	       "1:"	/* Standard return.  */
	       /* Return to saved PC.  */
	       "jmp %1" : /* No outputs.  */ :
	       "g" (8), "g" (env.__pc));

  /* Jump here when the FP saved in ENV points
     to a function that has already returned.  */
  asm volatile("latejump:");
  __libc_fatal("longjmp: Attempt to jump to a function that has returned.\n");
}