common/memory.c

/*
 * memory.c
 *
 * Copyright (c) 2011 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <common.h>

/*
 * Begin and End of memory area for malloc(), and current "brk"
 */
static unsigned long malloc_start;
static unsigned long malloc_end;
static unsigned long malloc_brk;

unsigned long mem_malloc_start(void)
{
	return malloc_start;
}

unsigned long mem_malloc_end(void)
{
	return malloc_end;
}

void mem_malloc_init(void *start, void *end)
{
	malloc_start = (unsigned long)start;
	malloc_end = (unsigned long)end;
	malloc_brk = malloc_start;
}

static void *sbrk_no_zero(ptrdiff_t increment)
{
	unsigned long old = malloc_brk;
	unsigned long new = old + increment;

	if ((new < malloc_start) || (new > malloc_end))
		return NULL;

	malloc_brk = new;

	return (void *)old;
}

void *sbrk(ptrdiff_t increment)
{
	void *old = sbrk_no_zero(increment);

	/* Only clear increment, if valid address was returned */
	if (old != NULL)
		memset(old, 0, increment);

	return old;
}