bbstart.s revision 1.11
1 /* $NetBSD: bbstart.s,v 1.11 2002/01/26 13:18:58 aymeric Exp $ */ 2 3 /*- 4 * Copyright (c) 1996 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Ignatios Souvatzis. 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 <machine/asm.h> 40 #include "aout2bb.h" 41 42 #define LVOAllocMem -0x0c6 43 #define LVODoIO -0x1c8 44 #define LVOCacheClearU -0x27c 45 46 #define IOcmd 28 47 #define IOerr 31 48 #define IOlen 36 49 #define IObuf 40 50 #define IOoff 44 51 52 #define Cmd_Rd 2 53 54 .text 55 #if defined(_PRIMARY_BOOT) || defined(AUTOLOAD) 56 Lzero: .asciz "DOS" | "DOS type" 57 #else 58 Lzero: .ascii "BOOT" | Secondary Boot 59 #endif 60 /* 61 * We put the relocator version here, for aout2bb, which replaces 62 * it with the bootblock checksum. 63 */ 64 Chksum: .long RELVER_RELATIVE_BYTES_FORWARD 65 Filesz: .long 8192 | dummy 66 67 /* 68 * Entry point from Kickstart. 69 * A1 points to an IOrequest, A6 points to ExecBase, we have a stack. 70 * _must_ be at offset 12. 71 */ 72 ENTRY_NOPROFILE(start) 73 #ifdef AUTOLOAD 74 jra Lautoload 75 #else 76 jra Lrelocate 77 #endif 78 79 Lreltab: 80 .word 0 | aout2bb puts the reloc table address here 81 82 .globl _C_LABEL(default_command) 83 _C_LABEL(default_command): 84 .asciz "netbsd -ASn2" 85 .org (_C_LABEL(default_command)+32) 86 87 #ifdef AUTOLOAD 88 /* 89 * autoload 90 */ 91 Lautoload: 92 movl %a6,%sp@- |SysBase 93 movl %a1,%sp@- |IORequest 94 95 movl #AUTOLOAD,%d0 |Howmuch 96 movl %d0,%a1@(IOlen) | for the actual read... 97 movl #0x10001,%d1 |MEMF_CLEAR|MEMF_PUBLIC 98 jsr %a6@(LVOAllocMem) 99 movl %sp@+,%a1 |IORequest 100 movl %sp@+,%a6 |SysBase 101 orl %d0,%d0 102 jne Lgotmem 103 movql #1,%d0 104 rts 105 106 Lgotmem: 107 movl %d0,%sp@- |Address 108 movl %a1@(IOoff),%sp@- |Old offset 109 movl %a1,%sp@- 110 movl %a6,%sp@- 111 112 /* we've set IOlen above */ 113 movl %d0,%a1@(IObuf) 114 movw #Cmd_Rd,%a1@(IOcmd) 115 jsr %a6@(LVODoIO) 116 117 movl %sp@+,%a6 118 movl %sp@+,%a1 119 movl %sp@+,%a1@(IOoff) 120 121 tstb %a1@(IOerr) 122 jne Lioerr 123 addl #Lrelocate-Lzero,%sp@ 124 125 movl %a6,%sp@- 126 jsr %a6@(LVOCacheClearU) 127 movl %sp@+,%a6 128 rts 129 Lioerr: 130 movql #1,%d0 131 addql #4,%sp 132 rts 133 #endif 134 135 /* 136 * Relocate ourselves, at the same time clearing the relocation table 137 * (in case it overlaps with BSS). 138 * 139 * Register usage: 140 * A2: points into the reloc table, located at our end. 141 * A0: pointer to the longword to relocate. 142 * D0: word offset of longword to relocate 143 * D1: points to our start. 144 * 145 * Table has relative byte offsets, if a byte offset is zero, it is 146 * followed by an absolute word offset. If this is zero, too, table 147 * end is reached. 148 */ 149 150 Lrelocate: 151 lea %pc@(Lzero),%a0 152 movl %a0,%d1 153 movw %pc@(Lreltab),%a2 154 addl %d1,%a2 155 jra Loopend 156 157 Loopw: 158 clrw %a2@+ 159 movl %d1,%a0 | for a variant with relative words, erase this line 160 Loopb: 161 addl %d0,%a0 162 addl %d1,%a0@ 163 Loopend: 164 movq #0,%d0 165 movb %a2@,%d0 166 clrb %a2@+ | bfclr %a2@+{0:8} is still two shorts 167 tstb %d0 | we could save one short by using casb %d0,d0,%a2@+ 168 jne Loopb 169 170 movw %a2@,%d0 171 jne Loopw 172 173 Lendtab: 174 movl %a6,%sp@- 175 jsr %a6@(LVOCacheClearU) 176 movl %sp@+,%a6 177 178 /* We are relocated. Now it is safe to initialize _SysBase: */ 179 180 movl %a6,_C_LABEL(SysBase) 181 182 #ifndef _PRIMARY_BOOT 183 movl %a5,%sp@- | Console info 184 #endif 185 movl %a1,%sp@- 186 bsr _C_LABEL(pain) 187 #ifdef _PRIMARY_BOOT 188 addql #4,%sp 189 #else 190 addql #8,%sp 191 #endif 192 193 Lerr: 194 movq #1,%d0 195 rts 196 197 .comm _C_LABEL(SysBase),4 198
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