/*
 * Copyright (c) 1986 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */
#include "param.h"
#include "user.h"
#include "proc.h"
#include "vm.h"
#include "systm.h"

void
brk()
{
	struct a {
		int naddr;
	};
	register int newsize, d;

	/* set newsize to new data size */
	newsize = ((struct a*)u.u_arg)->naddr - u.u_procp->p_daddr;
	if (newsize < 0)
		newsize = 0;
	if (u.u_tsize + newsize + u.u_ssize > MAXMEM) {
		u.u_error = ENOMEM;
		return;
	}

	u.u_procp->p_dsize = newsize;

	/* set d to (new - old) */
	d = newsize - u.u_dsize;
//printf ("brk: new size %u bytes, incremented by %d\n", newsize, d);
	if (d > 0)
		bzero ((void*) (u.u_procp->p_daddr + u.u_dsize), d);
	u.u_dsize = newsize;
        u.u_rval = u.u_procp->p_daddr + u.u_dsize;
}