/*- * Copyright (c) 2007-2008 *      Bill Paul <wpaul@windriver.com>.  All rights reserved. * * 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 Bill Paul. * 4. Neither the name of the author nor the names of any co-contributors *    may be used to endorse or promote products derived from this software *    without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``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 Bill Paul OR THE VOICES IN HIS HEAD * 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. */#define _ASM#include "data.h"/* * Bootstrap code, enter protected mode. */	.globl	boot	.textboot:	.code16	cli	cld	/* Clear segment registers */        ljmp    $0, $setcssetcs:        xor     %ax, %ax        mov     %ax, %ds        mov     %ax, %ss        /* Set up a temporary stack. */        mov     $boot, %sp#ifdef notdef	/*         * See if BIOS supports 'fast' A20 method.         * Note: this BIOS call, at least on my laptop, has been	 * seen to cause a small amount of memory corruption.	 * Until I can figure out why, we'll skip the shortcut	 * method and always use the keyboard controller	 * method.	 */	mov	$0x2403, %ax	int	$0x15	jc	no_fast	cmp	$0, %ah	jne	no_fast	and	$2, %bx	je	no_fast	/* Attempt to set A20 line. */	inb	$0x92, %al	testb	$2, %al	jnz	A20alreadyset	orb	$2, %al	and	$0xFE, %al	outb	%al, $0x92	jmp	A20alreadysetno_fast:#endif	/* Issue command to read output port. */	call	kbd_wait	mov	$0xD0, %al	outb	%al, $0x64	/* Wait until output data ready. */no_output:	inb	$0x64, %al	test	$1, %al	jz	no_output	/* Read data */	inb	$0x60, %al	/* Set A20 enable bit */	or	$2, %al	mov	%al, %ah	/* Issue command to write output port */	call	kbd_wait	mov	$0xD1, %al	outb	%al, $0x64	/* Write command to enable A20. */	call	kbd_wait	mov	%ah, %al	outb	%al, $0x60	/* Wait for completion. */	call	kbd_waitA20alreadyset:	/* Clear segment registers */	xor	%ax, %ax	mov	%ax, %es	mov	%ax, %fs	mov	%ax, %gs	/* Save BIOS disk device info */	mov	%dl, EXT(bios_disk)	/* Load GDT */	lgdtw	%fs:EXT(GDESC)	/* Set PE bit in CR0 and enable the cache */	mov	%cr0, %eax	or	$CR0_PE, %eax	and	$~CR0_CD, %eax	mov	%eax, %cr0	/* Do a jump to flush the instruction pipe */	jmp	s1s1:	/* Load segments for protected mode */	mov	$GDT_PDATA, %ax	mov	%ax, %ds	mov	%ax, %es	mov	%ax, %fs	mov	%ax, %gs	mov	%ax, %ss	/* Do a long jump to enter protected mode (sets %cs). */	ljmp	$GDT_PCODE, $s2s2:	/* Now we're in protected mode */	.code32	/* Initialize the stack */	mov	$STACK_PROT, %esp	/* Jump to C entry point. */	call	FUNC(_main)#ifndef SILENT	/* If the main routine returns, reboot the system. */	push	$reboot	call	FUNC(printf)#endif	/* Try to do a powerdown first. */	call	FUNC(bios_apm_shutdown)	/*	 * If that didn't work, triple fault the CPU to reset.	 * Load an empty IDT and then trigger an illegal instruction         * interrupt.	 */	sti	lidt	EXT(IDESC)	int	$0x6	/* If that didn't work, just hang. */stop:	hlt	jmp	stop/* * Wait until i8042 keyboard controller is * ready to accept a command or data byte */	.code16delay0:	jmp	d1d1:	inb	$0x60, %alkbd_wait:	jmp	d2d2:	inb	$0x64, %al	test	$1, %al	jnz	delay0	test	$2, %al	jnz	kbd_wait	ret	.code32#ifndef SILENT	.datareboot:	.string "Rebooting...\n"#endif