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guile/libguile/continuations.h
Andy Wingo bfffd2583c make call/cc capture and restore the vm stacks
* libguile/continuations.c (scm_make_continuation): Capture VM
  continuations as well, as their stack is outside the C stack.
  (copy_stack): Reinstate VM stacks with the C stack.

* libguile/continuations.h (scm_t_contregs): Add a pointer for VM stacks.
  A binary-incompatible change -- hopefully not too many people were
  messing around with this struct, though.

* libguile/vm-engine.c (vm_run): Add a note about possibly maintaining a
  stack of vms.

* libguile/vm.c (struct scm_vm_cont): New struct, distinct from scm_vm.
  (vm_cont_mark, vm_cont_free, capture_vm_cont, reinstate_vm_cont):
  Reorder some code, and fix some bad assumptions about what part of the
  stack to copy; obviously this code was never used.

* libguile/vm.h:
* libguile/vm.c (scm_vm_capture_continuations)
  (scm_vm_reinstate_continuations): New public functions, used by
  continuations.c.
2008-09-24 17:04:14 +02:00

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/* classes: h_files */
#ifndef SCM_CONTINUATIONS_H
#define SCM_CONTINUATIONS_H
/* Copyright (C) 1995,1996,2000,2001, 2006, 2008 Free Software Foundation, Inc.
*
* This 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.
*
* This 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 this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libguile/__scm.h"
#ifdef __ia64__
#include <signal.h>
#include <ucontext.h>
#endif /* __ia64__ */
/* a continuation SCM is a non-immediate pointing to a heap cell with:
word 0: bits 0-15: smob type tag: scm_tc16_continuation.
bits 16-31: unused.
word 1: malloc block containing an scm_t_contregs structure with a
tail array of SCM_STACKITEM. the size of the array is stored
in the num_stack_items field of the structure.
*/
SCM_API scm_t_bits scm_tc16_continuation;
typedef struct
{
SCM throw_value;
jmp_buf jmpbuf;
SCM dynenv;
#ifdef __ia64__
void *backing_store;
unsigned long backing_store_size;
#endif /* __ia64__ */
size_t num_stack_items; /* size of the saved stack. */
SCM root; /* continuation root identifier. */
SCM vm_conts; /* vm continuations (they use separate stacks) */
/* The offset from the live stack location to this copy. This is
used to adjust pointers from within the copied stack to the stack
itself.
Thus, when you read a pointer from the copied stack that points
into the live stack, you need to add OFFSET so that it points
into the copy.
*/
scm_t_ptrdiff offset;
/* The most recently created debug frame on the live stack, before
it was saved. This needs to be adjusted with OFFSET, above.
*/
struct scm_t_debug_frame *dframe;
SCM_STACKITEM stack[1]; /* copied stack of size num_stack_items. */
} scm_t_contregs;
#define SCM_CONTINUATIONP(x) SCM_TYP16_PREDICATE (scm_tc16_continuation, x)
#define SCM_CONTREGS(x) ((scm_t_contregs *) SCM_CELL_WORD_1 (x))
#define SCM_CONTINUATION_LENGTH(x) (SCM_CONTREGS (x)->num_stack_items)
#define SCM_SET_CONTINUATION_LENGTH(x, n)\
(SCM_CONTREGS (x)->num_stack_items = (n))
#define SCM_JMPBUF(x) ((SCM_CONTREGS (x))->jmpbuf)
#define SCM_DYNENV(x) ((SCM_CONTREGS (x))->dynenv)
#define SCM_THROW_VALUE(x) ((SCM_CONTREGS (x))->throw_value)
#define SCM_CONTINUATION_ROOT(x) ((SCM_CONTREGS (x))->root)
#define SCM_DFRAME(x) ((SCM_CONTREGS (x))->dframe)
SCM_API SCM scm_make_continuation (int *first);
SCM_API void *scm_c_with_continuation_barrier (void *(*func)(void*), void *);
SCM_API SCM scm_with_continuation_barrier (SCM proc);
SCM_INTERNAL SCM
scm_i_with_continuation_barrier (scm_t_catch_body body,
void *body_data,
scm_t_catch_handler handler,
void *handler_data,
scm_t_catch_handler pre_unwind_handler,
void *pre_unwind_handler_data);
SCM_INTERNAL void scm_init_continuations (void);
#endif /* SCM_CONTINUATIONS_H */
/*
Local Variables:
c-file-style: "gnu"
End:
*/