ocaml/byterun/stacks.c

102 lines
3.3 KiB
C

/***********************************************************************/
/* */
/* Objective Caml */
/* */
/* Xavier Leroy, projet Cristal, INRIA Rocquencourt */
/* */
/* Copyright 1996 Institut National de Recherche en Informatique et */
/* en Automatique. All rights reserved. This file is distributed */
/* under the terms of the GNU Library General Public License. */
/* */
/***********************************************************************/
/* $Id$ */
/* To initialize and resize the stacks */
#include <string.h>
#include "config.h"
#include "fail.h"
#include "misc.h"
#include "mlvalues.h"
#include "stacks.h"
value * stack_low;
value * stack_high;
value * stack_threshold;
value * extern_sp;
value * trapsp;
value * trap_barrier;
value global_data;
unsigned long max_stack_size; /* also used in gc_ctrl.c */
void init_stack (long unsigned int initial_max_size)
{
stack_low = (value *) stat_alloc(Stack_size);
stack_high = stack_low + Stack_size / sizeof (value);
stack_threshold = stack_low + Stack_threshold / sizeof (value);
extern_sp = stack_high;
trapsp = stack_high;
trap_barrier = stack_high + 1;
max_stack_size = initial_max_size;
gc_message (0x08, "Initial stack limit: %luk bytes\n",
max_stack_size / 1024 * sizeof (value));
}
void realloc_stack(asize_t required_space)
{
asize_t size;
value * new_low, * new_high, * new_sp;
value * p;
Assert(extern_sp >= stack_low);
size = stack_high - stack_low;
do {
if (size >= max_stack_size) raise_stack_overflow();
size *= 2;
} while (size < stack_high - extern_sp + required_space);
gc_message (0x08, "Growing stack to %luk bytes\n",
(unsigned long) size * sizeof(value) / 1024);
new_low = (value *) stat_alloc(size * sizeof(value));
new_high = new_low + size;
#define shift(ptr) \
((char *) new_high - ((char *) stack_high - (char *) (ptr)))
new_sp = (value *) shift(extern_sp);
memmove((char *) new_sp,
(char *) extern_sp,
(stack_high - extern_sp) * sizeof(value));
stat_free(stack_low);
trapsp = (value *) shift(trapsp);
trap_barrier = (value *) shift(trap_barrier);
for (p = trapsp; p < new_high; p = Trap_link(p))
Trap_link(p) = (value *) shift(Trap_link(p));
stack_low = new_low;
stack_high = new_high;
stack_threshold = stack_low + Stack_threshold / sizeof (value);
extern_sp = new_sp;
#undef shift
}
value ensure_stack_capacity(value required_space) /* ML */
{
asize_t req = Long_val(required_space);
if (extern_sp - req < stack_low) realloc_stack(req);
return Val_unit;
}
void change_max_stack_size (long unsigned int new_max_size)
{
asize_t size = stack_high - extern_sp + Stack_threshold / sizeof (value);
if (new_max_size < size) new_max_size = size;
if (new_max_size != max_stack_size){
gc_message (0x08, "Changing stack limit to %luk bytes\n",
new_max_size * sizeof (value) / 1024);
}
max_stack_size = new_max_size;
}