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      1 /*	$NetBSD: srt0.s,v 1.1 2007/12/17 19:09:54 garbled Exp $	*/
      2 
      3 /*
      4  * Copyright (C) 1996-1999 Cort Dougan (cort (at) fsmlasb.com).
      5  * Copyright (C) 1996-1999 Gary Thomas (gdt (at) osf.org).
      6  * Copyright (C) 1996-1999 Paul Mackeras (paulus (at) linuxcare.com).
      7  * All rights reserved.
      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 by TooLs GmbH.
     20  * 4. The name of TooLs GmbH may not be used to endorse or promote products
     21  *    derived from this software without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
     24  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     25  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     26  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     27  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     28  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     29  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     30  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     31  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     32  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     33  */
     34 
     35 #define MSR_IP		(1<<6)
     36 
     37 #define HID0_DCI	(1<<10)
     38 #define HID0_ICFI	(1<<11)
     39 #define	HID0_DCE	(1<<14)
     40 #define HID0_ICE	(1<<15)
     41 
     42 /* when we start, the IPLCB pointer is in r3, and the extended one is in r4 */
     43 
     44 	.text
     45 
     46 	.globl	_start
     47 _start:
     48 	bl	start
     49 start:
     50 	mr	11,3		/* save the IPLCB pointer in r11 */
     51 	mr	12,4		/* save the extended IPLCB in r12 */
     52 	li	3,MSR_IP	/* Establish default MSR value */
     53 	mtmsr	3
     54 	isync
     55 
     56 	mflr	7
     57 	bl	flush_icache
     58 	mfspr	3,1008
     59 	lis	4,~(HID0_ICE|HID0_DCE)@h
     60 	ori	4,4,~(HID0_ICE|HID0_DCE)@l
     61 	andc	3,3,4
     62 	mtspr	1008,3
     63 	mtlr	7
     64 
     65 /* We aren't passed our loadaddr, so leave it alone */
     66 #if 0
     67 /*
     68  * check if we need to relocate ourselves to the link addr or were we
     69  * loaded there to begin with -- Cort
     70  */
     71 	lis	4,_start@h
     72 	ori	4,4,_start@l
     73 	mflr	3
     74 	subi	3,3,4		/* we get the nip, not the ip of the branch */
     75 	mr	8,3
     76 	cmpw	3,4
     77 	bne	relocate
     78 	b	start_ldr
     79 
     80 /*
     81  * no matter where we're loaded, move ourselves to -Ttext address
     82  */
     83 relocate:
     84 	lis	4,_start@h
     85 	ori	4,4,_start@l
     86 	lis	5,end@h
     87 	ori	5,5,end@l
     88 	addi	5,5,3		/* Round up - just in case */
     89 	sub	5,5,4		/* Compute # longwords to move */
     90 	srwi	5,5,2
     91 	mtctr	5
     92 	subi	3,3,4		/* Set up for loop */
     93 	subi	4,4,4
     94 2:
     95 	lwzu	5,4(3)
     96 	stwu	5,4(4)
     97 	bdnz	2b
     98   	lis	3,start_ldr@h
     99 	ori	3,3,start_ldr@l
    100 	mtlr	3		/* Easiest way to do an absolute jump */
    101 	blr
    102 #endif
    103 
    104 start_ldr:
    105 	mr	9,1		/* Save old stack pointer */
    106 	lis	1,.stack@h
    107 	ori	1,1,.stack@l
    108 	addi	1,1,4096
    109 	li	2,0x000F
    110 	andc	1,1,2
    111 	mr	3,11		/* arg1: IPLCB pointer */
    112 	mr	4,12		/* arg2: IPLCB extended block pointer */
    113 	bl	boot
    114 hang:
    115 	b	hang
    116 
    117 /*
    118  * Execute
    119  * run(startsym, endsym, args, bootinfo, entry)
    120  */
    121 	.globl  run
    122 run:
    123 	mtctr   7                       /* Entry point */
    124 	bctr
    125 
    126 /*
    127  * Flush instruction cache
    128  */
    129 	.globl flush_icache
    130 flush_icache:
    131 	mflr	5
    132 	bl	flush_dcache
    133 	mfspr	4,1008
    134 	li	4,0
    135 	ori	4,4,HID0_ICE|HID0_ICFI
    136 	or	3,3,4
    137 	mtspr	1008,3
    138 	andc	3,3,4
    139 	ori	3,3,HID0_ICE
    140 	mtspr	1008,3
    141 	mtlr	5
    142 	blr
    143 
    144 /*
    145  * Flush data cache
    146  */
    147 	.globl flush_dcache
    148 flush_dcache:
    149 	lis	3,0x1000@h
    150 	ori	3,3,0x1000@l
    151 	li	4,1024
    152 	mtctr	4
    153 1:
    154 	lwz	4,0(3)
    155 	addi	3,3,32
    156 	bdnz	1b
    157 	blr
    158 
    159 #if 0
    160 /*
    161  * write LEDS
    162  */
    163 
    164 	.globl led
    165 led:
    166 	mfmsr	5	/* save MSR to r5 */
    167 	lis	7,0xffff
    168 	ori	7,7,~(MSR_DR)
    169 	and	6,5,7
    170 	mtmsr	6
    171 	isync
    172 
    173 #endif
    174 /*
    175  * local stack
    176  */
    177 	.comm	.stack,8192,4
    178