start_pxe.S revision 1.2 
1/*	$NetBSD: start_pxe.S,v 1.2 2003/10/09 10:36:26 dsl Exp $	*/
2
3/*
4 * Copyright 2001 Wasabi Systems, Inc.
5 * All rights reserved.
6 *
7 * Written by Jason R. Thorpe for Wasabi Systems, Inc.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 *    must display the following acknowledgement:
19 *	This product includes software developed for the NetBSD Project by
20 *	Wasabi Systems, Inc.
21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse
22 *    or promote products derived from this software without specific prior
23 *    written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35 * POSSIBILITY OF SUCH DAMAGE.
36 */
37
38/*
39 * PXE startup
40 * parts from sys/arch/i386/stand/lib/crt/bootsect/start_bootsect.S
41 *
42 * See PXE SPEC 4.4.5 (pdf page 88)
43 */
44
45#include <machine/asm.h>
46#include <sys/bootblock.h>
47
48	.text
49ENTRY(start)
50	.code16
51	/* Boot parameter area in same format as boot and bootxx */
52	jmp	1f
53	.balign 4
54	.long	X86_BOOT_MAGIC_PXE
55bootparams:
56	.long	1f - bootparams
57#include <boot_params.S>
58	.space	4 * 4			/* some spare */
591:
60	# start is loaded at 0x0:0x7c00 but we want 0x7c0:0x0
61	# ljmp to the next instruction to adjust %cs
62	ljmp	$0x7c0, $2f
632:
64	# set up %ds
65	xorl	%eax, %eax
66	mov	%cs, %ax
67	mov	%ax, %ds
68
69	# set up %ss and %esp
70	mov	%ax, %ss
71	movl	$0xfffc, %esp		/* stack at top of 64k segment */
72
73	call	gdt_fixup
74
75	/* change to protected mode */
76	calll	_C_LABEL(real_to_prot)
77	.code32
78
79	/* clear bss */
80	xorl	%eax, %eax
81	movl	$_C_LABEL(edata), %edi
82	movl	$_C_LABEL(end), %ecx
83	subl	%edi, %ecx
84	cld
85	rep
86	stosb
87
88	/* ...and call main()! */
89	call	_C_LABEL(main)
90
91	.globl	_C_LABEL(exit)
92_C_LABEL(exit):
93	call	_C_LABEL(prot_to_real)
94	.code16
95	movw	$efail, %si
96	call	message
97
98#ifdef notyet
99	/* sleep for 3s = 0x2dc6c0 us */
100	movb	$0x86, %ah
101	mov	$0x002d, %cx
102	mov	$0xc6c0, %dx
103	int	$0x15
104
105	/* call ROM BASIC */
106	int	$0x18
107#else
10810:
109	cli
110	hlt
111	jmp	10b
112#endif
113
114efail:	.asciz		"Boot fail\r\n"
115