glibc/sysdeps/vax/__longjmp.c
1992-03-11 23:10:37 +00:00

101 lines
3.1 KiB
C

/* Copyright (C) 1991, 1992 Free Software Foundation, Inc.
Derived from @(#)_setjmp.s 5.7 (Berkeley) 6/27/88,
Copyright (c) 1980 Regents of the University of California.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <ansidecl.h>
#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
DEFUN(__longjmp, (env, val), CONST jmp_buf env AND 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");
}