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authorRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
committerRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
commit28f540f45bbacd939bfd07f213bcad2bf730b1bf (patch)
tree15f07c4c43d635959c6afee96bde71fb1b3614ee /sysdeps/vax/__longjmp.c
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+/* Copyright (C) 1991, 1992, 1994 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");
+}