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/* Copyright (C) 1995,1996 Free Software Foundation, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this software; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*
* As a special exception, the Free Software Foundation gives permission
* for additional uses of the text contained in its release of GUILE.
*
* The exception is that, if you link the GUILE library with other files
* to produce an executable, this does not by itself cause the
* resulting executable to be covered by the GNU General Public License.
* Your use of that executable is in no way restricted on account of
* linking the GUILE library code into it.
*
* This exception does not however invalidate any other reasons why
* the executable file might be covered by the GNU General Public License.
*
* This exception applies only to the code released by the
* Free Software Foundation under the name GUILE. If you copy
* code from other Free Software Foundation releases into a copy of
* GUILE, as the General Public License permits, the exception does
* not apply to the code that you add in this way. To avoid misleading
* anyone as to the status of such modified files, you must delete
* this exception notice from them.
*
* If you write modifications of your own for GUILE, it is your choice
* whether to permit this exception to apply to your modifications.
* If you do not wish that, delete this exception notice.
*/
#include <stdio.h>
#include "_scm.h"
/* {Continuations}
*/
static char s_cont[] = "continuation";
#ifdef __STDC__
SCM
scm_make_cont (SCM * answer)
#else
SCM
scm_make_cont (answer)
SCM * answer;
#endif
{
long j;
SCM cont;
#ifdef CHEAP_CONTINUATIONS
SCM_NEWCELL (cont);
*answer = cont;
SCM_DEFER_INTS;
SCM_SETJMPBUF (cont, scm_must_malloc ((long) sizeof (regs), s_cont));
SCM_CAR (cont) = scm_tc7_contin;
SCM_DYNENV (cont) = dynwinds;
SCM_THROW_VALUE = SCM_EOL;
SCM_BASE (cont) = SCM_BASE (rootcont);
SCM_SEQ (cont) = SCM_SEQ (rootcont);
SCM_ALLOW_INTS;
#else
register SCM_STACKITEM *src, *dst;
{
SCM winds;
for (winds = scm_dynwinds; winds != SCM_EOL; winds = SCM_CDR (winds))
{
#if 0
if (SCM_INUMP (SCM_CAR (winds)))
{
scm_relocate_chunk_to_heap (SCM_CAR (winds));
}
#endif
}
}
SCM_NEWCELL (cont);
*answer = cont;
SCM_DEFER_INTS;
SCM_FLUSH_REGISTER_WINDOWS;
j = scm_stack_size (SCM_BASE (scm_rootcont));
SCM_SETJMPBUF (cont,
scm_must_malloc ((long) (sizeof (regs) + j * sizeof (SCM_STACKITEM)),
s_cont));
SCM_SETLENGTH (cont, j, scm_tc7_contin);
SCM_DYNENV (cont) = scm_dynwinds;
SCM_THROW_VALUE (cont) = SCM_EOL;
src = SCM_BASE (cont) = SCM_BASE (scm_rootcont);
SCM_SEQ (cont) = SCM_SEQ (scm_rootcont);
SCM_ALLOW_INTS;
#ifndef SCM_STACK_GROWS_UP
src -= SCM_LENGTH (cont);
#endif /* ndef SCM_STACK_GROWS_UP */
dst = (SCM_STACKITEM *) (SCM_CHARS (cont) + sizeof (regs));
for (j = SCM_LENGTH (cont); 0 <= --j;)
*dst++ = *src++;
#endif /* def CHEAP_CONTINUATIONS */
#ifdef DEBUG_EXTENSIONS
SCM_DFRAME (cont) = last_debug_info_frame;
#endif
return cont;
}
void scm_dynthrow SCM_P ((SCM *a));
/* Grow the stack so that there is room */
/* to copy in the continuation. Then */
#ifndef CHEAP_CONTINUATIONS
#ifdef __STDC__
static void
grow_throw (SCM *a)
#else
static void
grow_throw (a)
SCM *a;
#endif
{ /* retry the throw. */
SCM growth[100];
growth[0] = a[0];
growth[1] = a[1];
growth[2] = a[2] + 1;
growth[3] = (SCM) a;
scm_dynthrow (growth);
}
#endif /* ndef CHEAP_CONTINUATIONS */
#ifdef __STDC__
void
scm_dynthrow (SCM *a)
#else
void
scm_dynthrow (a)
SCM *a;
#endif
{
SCM cont = a[0], val = a[1];
#ifndef CHEAP_CONTINUATIONS
register long j;
register SCM_STACKITEM *src, *dst = SCM_BASE (scm_rootcont);
#ifdef SCM_STACK_GROWS_UP
if (a[2] && (a - ((SCM *) a[3]) < 100))
#else
if (a[2] && (((SCM *) a[3]) - a < 100))
#endif
fputs ("grow_throw: check if SCM growth[100]; being optimized out\n",
stderr);
/* if (a[2]) fprintf(stderr, " ct = %ld, dist = %ld\n",
a[2], (((SCM *)a[3]) - a)); */
#ifdef SCM_STACK_GROWS_UP
if (SCM_PTR_GE (dst + SCM_LENGTH (cont), (SCM_STACKITEM *) & a))
grow_throw (a);
#else
dst -= SCM_LENGTH (cont);
if (SCM_PTR_LE (dst, (SCM_STACKITEM *) & a))
grow_throw (a);
#endif /* def SCM_STACK_GROWS_UP */
SCM_FLUSH_REGISTER_WINDOWS;
src = (SCM_STACKITEM *) (SCM_CHARS (cont) + sizeof (regs));
for (j = SCM_LENGTH (cont); 0 <= --j;)
*dst++ = *src++;
#ifdef sparc /* clear out stack up to this stackframe */
/* maybe this would help, maybe not */
/* bzero((void *)&a, sizeof(SCM_STACKITEM) * (((SCM_STACKITEM *)&a) -
(dst - SCM_LENGTH(cont)))) */
#endif
#endif /* ndef CHEAP_CONTINUATIONS */
#ifdef DEBUG_EXTENSIONS
last_debug_info_frame = SCM_DFRAME (cont);
#endif
SCM_THROW_VALUE(cont) = val;
longjmp (SCM_JMPBUF (cont), 1);
}
#ifdef __STDC__
SCM
scm_call_continuation (SCM cont, SCM val)
#else
SCM
scm_call_continuation (cont, val)
SCM cont;
SCM val;
#endif
{
SCM a[3];
a[0] = cont;
a[1] = val;
a[2] = 0;
if ( (SCM_SEQ (cont) != SCM_SEQ (scm_rootcont))
|| (SCM_BASE (cont) != SCM_BASE (scm_rootcont))) /* base compare not needed */
scm_wta (cont, "continuation from wrong top level", s_cont);
scm_dowinds (SCM_DYNENV (cont),
scm_ilength (scm_dynwinds) - scm_ilength (SCM_DYNENV (cont)));
scm_dynthrow (a);
return SCM_UNSPECIFIED; /* not reached */
}
#ifdef __STDC__
void
scm_init_continuations (void)
#else
void
scm_init_continuations ()
#endif
{
#include "continuations.x"
}
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