start.S revision 1.2
1 /* $NetBSD: start.S,v 1.2 2003/11/10 08:51:52 wiz Exp $ */ 2 /* 3 * Copyright (c) 1995 Ludd, University of Lule}, Sweden. 4 * All rights reserved. 5 * 6 * This code is derived from software contributed to Ludd by 7 * Bertram Barth. 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 at Ludd, University of 20 * Lule}, Sweden and its contributors. 21 * 4. The name of the author may not be used to endorse or promote products 22 * derived from this software without specific prior written permission 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 /* All bugs are subject to removal without further notice */ 37 38 39 #define _LOCORE 40 41 #include "sys/disklabel.h" 42 43 #include "../include/mtpr.h" 44 #include "../include/asm.h" 45 46 _C_LABEL(_start): 47 _C_LABEL(start): 48 .globl _C_LABEL(start) # this is the symbolic name for the start 49 .globl _C_LABEL(_start) # of code to be relocated. We can use this 50 # to get the actual/real address (pc-rel) 51 # or to get the relocated address (abs). 52 53 .org 0x00 # uVAX booted from TK50 starts here 54 brb from_0x00 # continue behind dispatch-block 55 56 .org 0x02 # information used by uVAX-ROM 57 .byte 0xcf # offset in words to identification area 58 .byte 1 # this byte must be 1 59 .word 0 # logical block number (word swapped) 60 .word 0 # of the secondary image 61 62 .org 0x08 # 63 brb from_0x08 # skip ... 64 65 .org 0x0C # 11/750 & 8200 starts here 66 movzbl $1,_C_LABEL(from)# We booted from "old" rom. 67 brw cont_750 68 69 70 from_0x00: # uVAX from TK50 71 brw start_uvax # all uVAXen continue there 72 73 from_0x08: # Any machine from VMB 74 movzbl $4,_C_LABEL(from) # Booted from full VMB 75 brw start_vmb 76 77 # the complete area reserved for label 78 # must be empty (i.e. filled with zeroes). 79 # disklabel(8) checks that before installing 80 # the bootblocks over existing label. 81 82 .org LABELOFFSET 83 .globl _C_LABEL(romlabel) 84 _C_LABEL(romlabel): 85 .long 0 86 87 .org LABELOFFSET + d_end_ 88 start_vmb: 89 /* 90 * Read in block 1-15. 91 */ 92 movl 52(%r11), %r7 # load iovec/bqo into %r7 93 addl3 (%r7), %r7, %r6 # load qio into %r6 94 pushl %r11 # base of rpb 95 pushl $0 # virtual-flag 96 pushl $33 # read-logical-block 97 pushl $1 # lbn to start reading 98 pushl $7680 # number of bytes to read 99 pushab start_uvax # buffer-address 100 calls $6, (%r6) # call the qio-routine 101 brw start_uvax 102 103 /* 104 * Parameter block for uVAX boot. 105 */ 106 #define VOLINFO 0 /* 1=single-sided 81=double-sided volumes */ 107 #define SISIZE 16 /* size in blocks of secondary image */ 108 #define SILOAD 0 /* load offset (usually 0) from the default */ 109 #define SIOFF 0x200 /* byte offset into secondary image */ 110 111 .org 0x19e 112 .byte 0x18 # must be 0x18 113 .byte 0x00 # must be 0x00 (MBZ) 114 .byte 0x00 # any value 115 .byte 0xFF - (0x18 + 0x00 + 0x00) 116 /* 4th byte holds 1s' complement of sum of previous 3 bytes */ 117 118 .byte 0x00 # must be 0x00 (MBZ) 119 .byte VOLINFO 120 .byte 0x00 # any value 121 .byte 0x00 # any value 122 123 .long SISIZE # size in blocks of secondary image 124 .long SILOAD # load offset (usually 0) 125 .long SIOFF # byte offset into secondary image 126 .long (SISIZE + SILOAD + SIOFF) # sum of previous 3 127 128 129 .align 2 130 .globl _C_LABEL(from) 131 _C_LABEL(from): 132 .long 0 133 134 /* 135 * After bootblock (LBN0) has been loaded into the first page 136 * of good memory by 11/750's ROM-code (transfer address 137 * of bootblock-code is: base of good memory + 0x0C) registers 138 * are initialized as: 139 * R0: type of boot-device 140 * 0: Massbus device 141 * 1: RK06/RK07 142 * 2: RL02 143 * 17: UDA50 144 * 35: TK50 145 * 64: TU58 146 * R1: (UBA) address of UNIBUS I/O-page 147 * (MBA) address of boot device's adapter 148 * R2: (UBA) address of the boot device's CSR 149 * (MBA) controller number of boot device 150 * R6: address of driver subroutine in ROM 151 * 152 * cont_750 reads in LBN1-15 for further execution. 153 */ 154 cont_750: 155 movl $_C_LABEL(start), %sp # move stack to avoid clobbering the code 156 pushr $0x131 # save clobbered registers 157 clrl %r4 # %r4 == # of blocks transferred 158 movab _C_LABEL(start),%r5 # %r5 have base address for next transfer 159 pushl %r5 # ...on stack also (Why?) 160 1: incl %r4 # increment block count 161 movl %r4,%r8 # LBN is in %r8 for rom routine 162 addl2 $0x200,%r5 # Increase address for next read 163 cmpl $16,%r4 # read 15 blocks? 164 beql 2f # Yep 165 movl %r5,(%sp) # move address to stack also 166 jsb (%r6) # read 512 bytes 167 blbs %r0,1b # jump if read succeeded 168 halt # otherwise die... 169 2: tstl (%sp)+ # remove boring arg from stack 170 popr $0x131 # restore clobbered registers 171 brw start_all # Ok, continue... 172 173 /* uVAX main entry is at the start of the second disk block. This is 174 * needed for multi-arch CD booting where multiple architecture need 175 * to shove stuff in boot block 0. 176 */ 177 .org 0x200 # uVAX booted from disk starts here 178 179 start_uvax: 180 movzbl $2,_C_LABEL(from) # Booted from subset-VMB 181 brb start_all 182 183 /* 184 * start_all: stack already at RELOC, we save registers, move ourself 185 * to RELOC and loads boot. 186 */ 187 start_all: 188 movl $_C_LABEL(start), %sp # move stack to a better 189 pushr $0x1fff # save all regs, used later. 190 191 subl3 $_C_LABEL(start), $_C_LABEL(edata), %r0 192 # get size of text+data (w/o bss) 193 moval _C_LABEL(start), %r1 # get actual base-address of code 194 subl3 $_C_LABEL(start), $_C_LABEL(end), %r2 195 # get complete size (incl. bss) 196 movl $_C_LABEL(start), %r3 # get relocated base-address of code 197 movc5 %r0, (%r1), $0, %r2, (%r3) # copy code to new location 198 199 movpsl -(%sp) 200 movl $relocated, -(%sp) # return-address on top of stack 201 rei # can be replaced with new address 202 relocated: # now relocation is done !!! 203 movl %sp, _C_LABEL(bootregs) 204 calls $0, _C_LABEL(Xmain) # call Xmain (gcc workaround)which is 205 halt # not intended to return ... 206 207 /* 208 * hoppabort() is called when jumping to the newly loaded program. 209 */ 210 ENTRY(hoppabort, 0) 211 movl 4(%ap),%r6 212 movl _C_LABEL(rpb),%r11 213 mnegl $1,%ap # Hack to figure out boot device. 214 movpsl -(%sp) 215 pushab 2(%r6) 216 mnegl $1,_C_LABEL(vax_load_failure) 217 rei 218 # calls $0,(%r6) 219 halt 220 221 ENTRY(unit_init, R6|R7|R8|R9|R10|R11) 222 mfpr $17,%r7 # Wanted bu KDB 223 movl 4(%ap),%r0 # init routine address 224 movl 8(%ap),%r9 # RPB in %r9 225 movl 12(%ap),%r1 # VMB argument list 226 callg (%r1),(%r0) 227 ret 228 229 # A bunch of functions unwanted in boot blocks. 230 ENTRY(getchar, 0) 231 halt 232 233 #ifndef USE_PRINTF 234 ENTRY(putchar, 0) 235 ret 236 237 ENTRY(printf, 0) 238 ret 239 #endif 240 241 ENTRY(panic, 0) 242 halt 243
Indexes created Mon Sep 29 15:09:53 GMT 2025