xref: /netbsd-src/sys/arch/ews4800mips/stand/common/start.S (revision 8ac07aec990b9d2e483062509d0a9fa5b4f57cf2)
1/*	$NetBSD: start.S,v 1.1 2005/12/29 15:20:09 tsutsui Exp $	*/
2
3/*-
4 * Copyright (c) 2004 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by UCHIYAMA Yasushi.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 *    must display the following acknowledgement:
20 *        This product includes software developed by the NetBSD
21 *        Foundation, Inc. and its contributors.
22 * 4. Neither the name of The NetBSD Foundation nor the names of its
23 *    contributors may be used to endorse or promote products derived
24 *    from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38
39#include <mips/regdef.h>
40
41	.set	noreorder
42	.set	mips3
43	.align	2
44	.text
45/*
46 * Entry point.
47 */
48	.globl	start
49start:
50	nop
51	nop
52	nop
53	nop
54	la	sp, _ftext
55
56	mfc0	t0, $12
57	lui	t1, 0x0040	/* BEV : use IPL's exception vector. */
58	and	t0, t0, t1
59	mtc0	t0, $12
60	nop
61	la	t0, main
62	move	a1, v0
63	jr	t0
64	 move	a2, v1		/* v1 = mainfo */
651:	b	1b
66	 nop
67	/* NOTREACHED */
68
69#if 0 /* ROM putc test */
70	li	a0, 50		/* x-pos */
712:	li	a2, 90		/* 'Z' */
72	lui	v0, 0xbfc0
73	ori	v0, 0xff60
74	li	a1, 50		/* y-pos */
75	jal	v0
76	 nop
77	b	2b
78	 addiu	a0, a0, 12
79	/* NOTREACHED */
80#endif
81#if 0 /* Frame buffer (TLB kseg2 mapped by IPL) test */
82	move	a3, zero
83	xori	a3, a3, 0x00
843:	sll	v0, a3, 0x18
85	sra	a2, v0, 0x18
86	lui	a0, 0xf000
87	move	v1, zero
88	lui	a1, 0x1
89	ori	a1, a1, 0xffff
902:	sb	a2, 0(a0)
91	addiu	v1, v1, 1
92	slt	v0, a1, v1
93	addiu	a0, a0, 1
94	beqz	v0, 2b
95	 nop
96	xori	a3, a3, 0xff
97	j	3b
98	 nop
99	/* NOTREACHED */
100#endif
101
102/*
103 * void tlb_read(int index, void *)
104 */
105	.global	tlb_read
106	.ent	tlb_read
107tlb_read:
108	mtc0	a0, $0		/* Index Register */
109	nop; nop; nop; nop;
110	tlbr
111	nop; nop; nop; nop;
112	mfc0	t0, $5		/* PageMask */
113	nop; nop; nop; nop;
114	mfc0	t1, $10		/* EntryHi */
115	nop; nop; nop; nop;
116	mfc0	t2, $2		/* EntryLo0 */
117	nop; nop; nop; nop;
118	mfc0	t3, $3		/* EntryLo1 */
119	nop; nop; nop; nop;
120	sw	t0,  0(a1)
121	sw	t1,  4(a1)
122	sw	t2,  8(a1)
123	sw	t3, 12(a1)
124	jr	ra
125	 nop
126	.end	tlb_read
127