base_conv_mem_init.c

基于组件方式开发操作系统的OSKIT源代码

/*
 * Copyright (c) 1997-1999 University of Utah and the Flux Group.
 * All rights reserved.
 * 
 * This file is part of the Flux OSKit.  The OSKit is free software, also known
 * as "open source;" you can redistribute it and/or modify it under the terms
 * of the GNU General Public License (GPL), version 2, as published by the Free
 * Software Foundation (FSF).  To explore alternate licensing terms, contact
 * the University of Utah at [e-mail] or [phone].
 * 
 * The OSKit 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 GPL for more details.  You should have
 * received a copy of the GPL along with the OSKit; see the file COPYING.  If
 * not, write to the FSF, 59 Temple Place #330, Boston, MA 02111-1307, USA.
 */

#include <oskit/debug.h>
#include <oskit/c/stdio.h>
#include <oskit/x86/base_vm.h>
#include <oskit/x86/base_trap.h>
#include <oskit/x86/pc/phys_lmm.h>
#include <oskit/x86/pc/base_real.h>

void base_conv_mem_init(void)
{
	extern char _start[], _end[];
	struct trap_state ts;
	unsigned mem_size;
	unsigned start_pa = kvtophys(_start);
	unsigned end_pa = kvtophys(_end);

	/* Ask the BIOS for the size of conventional memory */
	ts.trapno = 0x12;
	ts.eflags = 0;
	base_real_int(&ts);

	mem_size = (ts.eax & 0xffff) * 1024;
	assert(mem_size >= 64*1024);
	assert(mem_size <= 640*1024);
	printf("Conventional memory: %dK\n", mem_size / 1024);

	/* Add the memory to our LMM pool */
#ifndef KNIT
	phys_lmm_init();
#endif
	if (start_pa >= mem_size) {
		phys_lmm_add(0x500, mem_size - 0x500);
	} else {
		if (start_pa > 0x500)
			phys_lmm_add(0x500, start_pa - 0x500);
		if (end_pa < mem_size)
			phys_lmm_add(end_pa, mem_size - end_pa);
	}
}