\f
-#include <stdio.h>
+#include <string.h>
+
#include "libguile/_scm.h"
#include "libguile/root.h"
#include "libguile/stackchk.h"
+#include "libguile/smob.h"
+#include "libguile/ports.h"
+#include "libguile/dynwind.h"
+#include "libguile/values.h"
+
#ifdef DEBUG_EXTENSIONS
#include "libguile/debug.h"
#endif
-#include "libguile/dynwind.h"
+#include "libguile/validate.h"
#include "libguile/continuations.h"
\f
/* {Continuations}
*/
-static char s_cont[] = "continuation";
+scm_bits_t scm_tc16_continuation;
-static void scm_dynthrow (SCM, SCM);
+static SCM
+continuation_mark (SCM obj)
+{
+ scm_contregs *continuation = SCM_CONTREGS (obj);
+ scm_gc_mark (continuation->throw_value);
+ scm_mark_locations (continuation->stack, continuation->num_stack_items);
+ return continuation->dynenv;
+}
-#ifndef CHEAP_CONTINUATIONS
+static scm_sizet
+continuation_free (SCM obj)
+{
+ scm_contregs *continuation = SCM_CONTREGS (obj);
+ /* stack array size is 1 if num_stack_items is 0 (rootcont). */
+ scm_sizet extra_items = (continuation->num_stack_items > 0)
+ ? (continuation->num_stack_items - 1)
+ : 0;
+ scm_sizet bytes_free = sizeof (scm_contregs)
+ + extra_items * sizeof (SCM_STACKITEM);
+
+ scm_must_free (continuation);
+ return bytes_free;
+}
+static int
+continuation_print (SCM obj, SCM port, scm_print_state *state)
+{
+ scm_contregs *continuation = SCM_CONTREGS (obj);
+
+ scm_puts ("#<continuation ", port);
+ scm_intprint (continuation->num_stack_items, 10, port);
+ scm_puts (" @ ", port);
+ scm_intprint (SCM_CELL_WORD_1 (obj), 16, port);
+ scm_putc ('>', port);
+ return 1;
+}
+/* this may return more than once: the first time with the escape
+ procedure, then subsequently with the value to be passed to the
+ continuation. */
+#define FUNC_NAME "scm_make_continuation"
SCM
-scm_make_cont (SCM *answer)
+scm_make_continuation (int *first)
{
- long j;
- SCM cont;
+ volatile SCM cont;
+ scm_contregs *continuation;
+ scm_contregs *rootcont = SCM_CONTREGS (scm_rootcont);
+ long stack_size;
SCM_STACKITEM * src;
- SCM_STACKITEM * dst;
- SCM_NEWCELL (cont);
- *answer = cont;
SCM_ENTER_A_SECTION;
SCM_FLUSH_REGISTER_WINDOWS;
- j = scm_stack_size (SCM_BASE (scm_rootcont));
- SCM_SET_CONTREGS (cont,
- scm_must_malloc (sizeof (scm_contregs)
- + j * sizeof (SCM_STACKITEM),
- s_cont));
- 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_SETLENGTH (cont, j, scm_tc7_contin);
- SCM_EXIT_A_SECTION;
-#ifndef SCM_STACK_GROWS_UP
- src -= SCM_LENGTH (cont);
-#endif /* ndef SCM_STACK_GROWS_UP */
- dst = (SCM_STACKITEM *) (SCM_CHARS (cont) + sizeof (scm_contregs));
-
- /* memcpy should be safe: src and dst will never overlap */
- memcpy (dst, src, sizeof (SCM_STACKITEM) * SCM_LENGTH (cont));
-
+ stack_size = scm_stack_size (rootcont->base);
+ continuation = scm_must_malloc (sizeof (scm_contregs)
+ + (stack_size - 1) * sizeof (SCM_STACKITEM),
+ FUNC_NAME);
+ continuation->num_stack_items = stack_size;
+ continuation->dynenv = scm_dynwinds;
+ continuation->throw_value = SCM_EOL;
+ continuation->base = src = rootcont->base;
+ continuation->seq = rootcont->seq;
#ifdef DEBUG_EXTENSIONS
- SCM_DFRAME (cont) = scm_last_debug_frame;
+ continuation->dframe = scm_last_debug_frame;
#endif
+ SCM_NEWSMOB (cont, scm_tc16_continuation, continuation);
+ SCM_EXIT_A_SECTION;
- return cont;
+#ifndef SCM_STACK_GROWS_UP
+ src -= stack_size;
+#endif
+ memcpy (continuation->stack, src, sizeof (SCM_STACKITEM) * stack_size);
+
+ if (setjmp (continuation->jmpbuf))
+ {
+ *first = 0;
+ return continuation->throw_value;
+ }
+ else
+ {
+ *first = 1;
+ return cont;
+ }
}
+#undef FUNC_NAME
+static void scm_dynthrow (SCM, SCM);
/* Grow the stack by a fixed amount to provide space to copy in the
* continuation. Possibly this function has to be called several times
* own frame are overwritten. Thus, memcpy can be used for best performance.
*/
static void
-copy_stack_and_call (SCM cont, SCM val,
- SCM_STACKITEM * src, SCM_STACKITEM * dst)
+copy_stack_and_call (scm_contregs *continuation, SCM val,
+ SCM_STACKITEM * dst)
{
- /* memcpy should be safe: src and dst will never overlap */
- memcpy (dst, src, sizeof (SCM_STACKITEM) * SCM_LENGTH (cont));
+ memcpy (dst, continuation->stack,
+ sizeof (SCM_STACKITEM) * continuation->num_stack_items);
#ifdef DEBUG_EXTENSIONS
- scm_last_debug_frame = SCM_DFRAME (cont);
+ scm_last_debug_frame = continuation->dframe;
#endif
- SCM_THROW_VALUE (cont) = val;
- longjmp (SCM_JMPBUF (cont), 1);
+ continuation->throw_value = val;
+ longjmp (continuation->jmpbuf, 1);
}
static void
scm_dynthrow (SCM cont, SCM val)
{
- SCM_STACKITEM * src;
+ scm_contregs *continuation = SCM_CONTREGS (cont);
SCM_STACKITEM * dst = SCM_BASE (scm_rootcont);
SCM_STACKITEM stack_top_element;
#ifdef SCM_STACK_GROWS_UP
- if (SCM_PTR_GE (dst + SCM_LENGTH (cont), & stack_top_element))
+ if (SCM_PTR_GE (dst + continuation->num_stack_items, &stack_top_element))
grow_stack (cont, val);
#else
- dst -= SCM_LENGTH (cont);
- if (SCM_PTR_LE (dst, & stack_top_element))
+ dst -= continuation->num_stack_items;
+ if (SCM_PTR_LE (dst, &stack_top_element))
grow_stack (cont, val);
#endif /* def SCM_STACK_GROWS_UP */
- SCM_FLUSH_REGISTER_WINDOWS;
- src = (SCM_STACKITEM *) (SCM_CHARS (cont) + sizeof (scm_contregs));
- copy_stack_and_call (cont, val, src, dst);
-}
-
-
-#else /* ifndef CHEAP_CONTINUATIONS */
-
-/* Dirk:FIXME:: It seems that nobody has ever tried to use this code, since it
- * contains syntactic errors and thus would not have compiled anyway.
- */
-
-
-SCM
-scm_make_cont (SCM *answer)
-{
- SCM cont;
-
- SCM_NEWCELL (cont);
- *answer = cont;
- SCM_ENTER_A_SECTION;
- SCM_SET_CONTREGS (cont, scm_must_malloc (sizeof (scm_contregs), s_cont));
- SCM_DYNENV (cont) = scm_dynwinds;
- SCM_THROW_VALUE = SCM_EOL;
- SCM_BASE (cont) = SCM_BASE (rootcont);
- SCM_SEQ (cont) = SCM_SEQ (rootcont);
- SCM_SETCAR (cont, scm_tc7_contin);
- SCM_EXIT_A_SECTION;
-
-#ifdef DEBUG_EXTENSIONS
- SCM_DFRAME (cont) = scm_last_debug_frame;
-#endif
-
- return cont;
-}
-
-static void
-scm_dynthrow (SCM cont, SCM val)
-{
-#ifdef DEBUG_EXTENSIONS
- scm_last_debug_frame = SCM_DFRAME (cont);
-#endif
- SCM_THROW_VALUE (cont) = val;
- longjmp (SCM_JMPBUF (cont), 1);
+ SCM_FLUSH_REGISTER_WINDOWS;
+ copy_stack_and_call (continuation, val, dst);
}
-#endif
-
-
-SCM
-scm_call_continuation (SCM cont, SCM val)
+static SCM
+continuation_apply (SCM cont, SCM args)
+#define FUNC_NAME "continuation_apply"
{
- 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_contregs *continuation = SCM_CONTREGS (cont);
+ scm_contregs *rootcont = SCM_CONTREGS (scm_rootcont);
+
+ if (continuation->seq != rootcont->seq
+ /* this base comparison isn't needed */
+ || continuation->base != rootcont->base)
+ {
+ SCM_MISC_ERROR ("continuation from wrong top level: ~S",
+ SCM_LIST1 (cont));
+ }
- scm_dowinds (SCM_DYNENV (cont),
- scm_ilength (scm_dynwinds) - scm_ilength (SCM_DYNENV (cont)));
+ scm_dowinds (continuation->dynenv,
+ scm_ilength (scm_dynwinds)
+ - scm_ilength (continuation->dynenv));
- scm_dynthrow (cont, val);
+ scm_dynthrow (cont, scm_values (args));
return SCM_UNSPECIFIED; /* not reached */
}
+#undef FUNC_NAME
void
scm_init_continuations ()
{
+ scm_tc16_continuation = scm_make_smob_type ("continuation", 0);
+ scm_set_smob_mark (scm_tc16_continuation, continuation_mark);
+ scm_set_smob_free (scm_tc16_continuation, continuation_free);
+ scm_set_smob_print (scm_tc16_continuation, continuation_print);
+ scm_set_smob_apply (scm_tc16_continuation, continuation_apply, 0, 0, 1);
+#ifndef SCM_MAGIC_SNARFER
#include "libguile/continuations.x"
+#endif
}
-
/*
Local Variables:
c-file-style: "gnu"
HCoop / bpt / guile.git / blobdiff