/*
	AB_list[s] holds the actual base of stack frame  s; this
	is the highest stack pointer of frame  s-1.
	Segments have the following numbers:
		-2			DATA_SEGMENT
		-1			HEAP_SEGMENT
		0, 1, .., curr_frame	stackframes
	Note that  AB_list[s] increases for decreasing s.
*/

/* $Header$ */

#include	"segcheck.h"
#include	"global.h"
#include	"mem.h"
#include	"alloc.h"

#ifdef	SEGCHECK

#define	ABLISTSIZE	100L		/* initial AB_list size */

#define	DATA_SEGMENT	-2
#define	HEAP_SEGMENT	-1

PRIVATE ptr *AB_list;
PRIVATE size frame_limit;
PRIVATE size curr_frame;

init_AB_list() {
	/* Allocate space for AB_list & initialize frame variables */

	frame_limit = ABLISTSIZE;
	curr_frame = 0L;
	AB_list = (ptr *) Malloc(frame_limit * sizeof (ptr), "AB_list");
	AB_list[curr_frame] = AB;
}

push_frame(p)
	ptr p;
{
	if (++curr_frame == frame_limit) {
		frame_limit = allocfrac(frame_limit);
		AB_list = (ptr *) Realloc((char *) AB_list,
				frame_limit * sizeof (ptr), "AB_list");
	}
	AB_list[curr_frame] = p;
}

pop_frames() {
	while (AB_list[curr_frame] < AB) {
		curr_frame--;
	}
}

int ptr2seg(p)
	ptr p;
{
	register int s;

	if (in_gda(p)) {
		s = DATA_SEGMENT;
	}
	else if (!in_stack(p)) {
		s = HEAP_SEGMENT;
	}
	else {
		for (s = curr_frame; s > 0; s--) {
			if (AB_list[s] > p)
				break;
		}
	}
	return s;
}

#else	SEGCHECK

init_AB_list() {}

push_frame() {}

pop_frames() {}

#endif	SEGCHECK