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start.S revision 1.1.76.1 
      1 /*	$NetBSD: start.S,v 1.1.76.1 2008/06/02 13:22:06 mjf 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  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <mips/regdef.h>
     33 
     34 	.set	noreorder
     35 	.set	mips3
     36 	.align	2
     37 	.text
     38 /*
     39  * Entry point.
     40  */
     41 	.globl	start
     42 start:
     43 	nop
     44 	nop
     45 	nop
     46 	nop
     47 	la	sp, _ftext
     48 
     49 	mfc0	t0, $12
     50 	lui	t1, 0x0040	/* BEV : use IPL's exception vector. */
     51 	and	t0, t0, t1
     52 	mtc0	t0, $12
     53 	nop
     54 	la	t0, main
     55 	move	a1, v0
     56 	jr	t0
     57 	 move	a2, v1		/* v1 = mainfo */
     58 1:	b	1b
     59 	 nop
     60 	/* NOTREACHED */
     61 
     62 #if 0 /* ROM putc test */
     63 	li	a0, 50		/* x-pos */
     64 2:	li	a2, 90		/* 'Z' */
     65 	lui	v0, 0xbfc0
     66 	ori	v0, 0xff60
     67 	li	a1, 50		/* y-pos */
     68 	jal	v0
     69 	 nop
     70 	b	2b
     71 	 addiu	a0, a0, 12
     72 	/* NOTREACHED */
     73 #endif
     74 #if 0 /* Frame buffer (TLB kseg2 mapped by IPL) test */
     75 	move	a3, zero
     76 	xori	a3, a3, 0x00
     77 3:	sll	v0, a3, 0x18
     78 	sra	a2, v0, 0x18
     79 	lui	a0, 0xf000
     80 	move	v1, zero
     81 	lui	a1, 0x1
     82 	ori	a1, a1, 0xffff
     83 2:	sb	a2, 0(a0)
     84 	addiu	v1, v1, 1
     85 	slt	v0, a1, v1
     86 	addiu	a0, a0, 1
     87 	beqz	v0, 2b
     88 	 nop
     89 	xori	a3, a3, 0xff
     90 	j	3b
     91 	 nop
     92 	/* NOTREACHED */
     93 #endif
     94 
     95 /*
     96  * void tlb_read(int index, void *)
     97  */
     98 	.global	tlb_read
     99 	.ent	tlb_read
    100 tlb_read:
    101 	mtc0	a0, $0		/* Index Register */
    102 	nop; nop; nop; nop;
    103 	tlbr
    104 	nop; nop; nop; nop;
    105 	mfc0	t0, $5		/* PageMask */
    106 	nop; nop; nop; nop;
    107 	mfc0	t1, $10		/* EntryHi */
    108 	nop; nop; nop; nop;
    109 	mfc0	t2, $2		/* EntryLo0 */
    110 	nop; nop; nop; nop;
    111 	mfc0	t3, $3		/* EntryLo1 */
    112 	nop; nop; nop; nop;
    113 	sw	t0,  0(a1)
    114 	sw	t1,  4(a1)
    115 	sw	t2,  8(a1)
    116 	sw	t3, 12(a1)
    117 	jr	ra
    118 	 nop
    119 	.end	tlb_read
    120