memmap.c

MIPS处理器的bootloader,龙芯就是用的修改过的PMON2

/* $Id: memmap.c,v 1.2 2003/08/10 11:15:26 pefo Exp $ */

/*
 * Copyright (c) 2001-2003 Opsycon AB  (www.opsycon.se / www.opsycon.com)
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by Opsycon AB, Sweden.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */
#include <pmon.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>

void	*kmemtop;
void	*memtop;
long	totalmemsize;

extern char     end[];
char           *allocp1 = end;
char           *heaptop = end + 65536;

MemDesc mem_root;

int
chg_heaptop (name, value)
	char *name, *value;
{
	u_int32_t top;

	if (atob (&top, value, 16)) {
		if(top < (u_int32_t)allocp1) {
			printf ("%x: heap is already above this point\n", top);
			return 0;
		}
		heaptop = (char *) top;
		return 1;
	}
	printf ("%s: invalid address\n", value);
	return 0;
}


char *
sbrk (n)
	int n;
{
	char *top;

	top = heaptop;
	if (!top) {
		top = (char *) CLIENTPC;
	}

	if ((allocp1 + n) <= top) {
		allocp1 += n;
		return (allocp1 - n);
	}

	return (0);
}

void
register_mem(void *start, void *end, int type, char *desc)
{
	MemDesc *cur = &mem_root;
	MemDesc *new, *prev;

	cur->start = (void *)0;
	cur->end = (void *)-1;

	new = malloc(sizeof(MemDesc));
	new->start = start;
	new->end = end;
	new->type = type;
	new->desc = desc;
	new->next = NULL;
	new->sub = NULL;

	do {
		/* Subsegment of current? */
		if (new->start >= cur->start && new->end <= cur->end) {
			if (cur->sub == NULL) {
				cur->sub = new;		/* First sub */
				return;
			}
			else if (cur->sub->start > new->end) {
				new->next = cur->sub;
				cur->sub = new;
				return;
			}
			else {
				cur = cur->sub;
			}
		}
		else {
			prev = cur;
			if (new->start > cur->end &&
			    cur->next && new->end < cur->next->start)
				break;

			cur = cur->next;
		}
	} while (cur);

	new->next = prev->next;
	prev->next = new;
}