sysdeps/i386/__longjmp.c

   1 /* Copyright (C) 1991, 1992, 1994, 1995 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 Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 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 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #ifndef __GNUC__
  20   #error This file uses GNU C extensions; you must compile with GCC.
  21 #endif
  22
  23 /* Put these global register declarations first, because we get an error if
  24    they come after any function definition, including inlines which might
  25    be in some header.  */
  26
  27 #define REGS \
  28   REG (bx);\
  29   REG (si);\
  30   REG (di);\
  31   REG (bp);\
  32   REG (sp)
  33
  34 #define REG(xx) register long int xx asm (#xx)
  35 REGS;
  36 #undef  REG
  37
  38 #include <ansidecl.h>
  39 #include <errno.h>
  40 #include <setjmp.h>
  41 #include <stdlib.h>
  42
  43 /* Jump to the position specified by ENV, causing the
  44    setjmp call there to return VAL, or 1 if VAL is 0.  */
  45 void
  46 DEFUN(__longjmp, (env, val),
  47       __jmp_buf env AND int val)
  48 {
  49   /* We specify explicit registers because, when not optimizing,
  50      the compiler will generate code that uses the frame pointer
  51      after it's been munged.  */
  52
  53   register CONST __typeof (env[0]) *e asm ("cx");
  54   register int v asm ("ax");
  55
  56   e = env;
  57   v = val == 0 ? 1 : val;
  58
  59 #define REG(xx) xx = (long int) e->__##xx
  60   REGS;
  61
  62   asm volatile ("jmp %*%0" : : "g" (e->__pc), "a" (v));
  63
  64   /* NOTREACHED */
  65   abort ();
  66 }