startit.s revision 1.8.130.1
1 /* $NetBSD: startit.s,v 1.8.130.1 2010/03/11 15:02:01 yamt Exp $ */ 2 3 /* 4 * Copyright (c) 1996 Ignatios Souvatzis 5 * Copyright (c) 1994 Michael L. Hitch 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * 29 * From: $NetBSD: startit.s,v 1.8.130.1 2010/03/11 15:02:01 yamt Exp $ 30 */ 31 #include <machine/asm.h> 32 33 .set ABSEXECBASE,4 34 35 .text 36 37 ENTRY_NOPROFILE(startit) 38 #if TESTONAMIGA 39 movew #0x999,0xdff180 | gray 40 #endif 41 #if TESTONDRACO 42 moveb #0,0x200003c8 43 moveb #31,0x200003c9 44 moveb #31,0x200003c9 45 moveb #31,0x200003c9 46 #endif 47 movel %sp,%a3 48 movel 4:w,%a6 49 lea %pc@(start_super:w),%a5 50 jmp %a6@(-0x1e) | supervisor-call 51 52 start_super: 53 #if TESTONAMIGA 54 movew #0x900,0xdff180 | dark red 55 #endif 56 movew #0x2700,%sr 57 58 | the BSD kernel wants values into the following registers: 59 | %a0: fastmem-start 60 | %d0: fastmem-size 61 | %d1: chipmem-size 62 | %d3: Amiga specific flags 63 | %d4: E clock frequency 64 | %d5: AttnFlags (cpuid) 65 | %d6: boot partition offset 66 | %d7: boothowto 67 | %a4: esym location 68 | %a2: Inhibit sync flags 69 | All other registers zeroed for possible future requirements. 70 71 lea %pc@(_C_LABEL(startit):w),%sp | make sure we have a good stack *** 72 73 movel %a3@(4),%a1 | loaded kernel 74 movel %a3@(8),%d2 | length of loaded kernel 75 | movel %a3@(12),%sp | entry point in stack pointer 76 movel %a3@(12),%a6 | entry point *** 77 movel %a3@(16),%a0 | fastmem-start 78 movel %a3@(20),%d0 | fastmem-size 79 movel %a3@(24),%d1 | chipmem-size 80 movel %a3@(28),%d7 | boothowto 81 movel %a3@(32),%a4 | esym 82 movel %a3@(36),%d5 | cpuid 83 movel %a3@(40),%d4 | E clock frequency 84 movel %a3@(44),%d3 | Amiga flags 85 movel %a3@(48),%a2 | Inhibit sync flags 86 movel %a3@(52),%d6 | boot partition offset 87 88 cmpb #0x7D,%a3@(36) | is it DraCo? 89 movel %a3@(56),%a3 | Load to fastmem flag 90 jeq nott | yes, switch off MMU later 91 92 | no, it is an Amiga: 93 94 #if TESTONAMIGA 95 movew #0xf00,0xdff180 |red 96 #endif 97 #if TESTONDRACO 98 moveb #0,0x200003c8 99 moveb #63,0x200003c9 100 moveb #0,0x200003c9 101 moveb #0,0x200003c9 102 #endif 103 104 movew #(1<<9),0xdff096 | disable DMA on Amigas. 105 106 | ------ mmu off start ----- 107 108 btst #3,%d5 | AFB_68040,SysBase->AttnFlags 109 jeq not040 110 111 | Turn off 68040/060 MMU 112 113 subl %a5,%a5 114 .word 0x4e7b,0xd003 | movec %a5,tc 115 .word 0x4e7b,0xd806 | movec %a5,urp 116 .word 0x4e7b,0xd807 | movec %a5,srp 117 .word 0x4e7b,0xd004 | movec %a5,itt0 118 .word 0x4e7b,0xd005 | movec %a5,itt1 119 .word 0x4e7b,0xd006 | movec %a5,dtt0 120 .word 0x4e7b,0xd007 | movec %a5,dtt1 121 jra nott 122 123 not040: 124 lea %pc@(zero:w),%a5 125 pmove %a5@,%tc | Turn off MMU 126 lea %pc@(nullrp:w),%a5 127 pmove %a5@,%crp | Turn off MMU some more 128 pmove %a5@,%srp | Really, really, turn off MMU 129 130 | Turn off 68030 TT registers 131 132 btst #2,%d5 | AFB_68030,SysBase->AttnFlags 133 jeq nott | Skip TT registers if not 68030 134 lea %pc@(zero:w),%a5 135 .word 0xf015,0x0800 | pmove %a5@,tt0 (gas only knows about 68851 ops..) 136 .word 0xf015,0x0c00 | pmove %a5@,tt1 (gas only knows about 68851 ops..) 137 138 nott: 139 | ---- mmu off end ---- 140 #if TESTONAMIGA 141 movew #0xf60,0xdff180 | orange 142 #endif 143 #if TESTONDRACO 144 moveb #0,0x200003c8 145 moveb #63,0x200003c9 146 moveb #24,0x200003c9 147 moveb #0,0x200003c9 148 #endif 149 150 151 | ---- copy kernel start ---- 152 153 | removed Z flag 154 | tstl %a3 | Can we load to fastmem? 155 | jeq L0 | No, leave destination at 0 156 movl %a0,%a3 | Move to start of fastmem chunk 157 addl %a0,%a6 | relocate kernel entry point 158 159 addl #3,%d2 160 andl #0xfffffffc,%d2 | round up. 161 162 | determine if the kernel need be copied upwards or downwards 163 164 cmpl %a1,%a3 | %a3-a1 165 bcs above | source is above 166 167 movl %a0,%sp 168 addl %d0,%sp | move the stack to the end of segment 169 170 | copy from below upwards requires copying from end to start. 171 172 addl %d2,%a3 | one long word past 173 addl %d2,%a1 | one long word past 174 175 subl #4,%sp | alloc space 176 movl %a1,%sp@- | save source 177 movl %a3,%sp@- | save destination 178 179 | copy copier to end of segment 180 181 movl %sp,%a3 182 subl #256,%a3 | end of segment save our stack 183 184 lea %pc@(_C_LABEL(startit_end):w),%a1 185 movl %a0,%sp@- | save segment start 186 lea %pc@(below:w),%a0 187 188 L0: movw %a1@-,%a3@- 189 cmpl %a0,%a1 190 bne L0 191 movl %sp@,%a0 | restore segment start 192 movl %a3,%sp@ | address of relocated below 193 addl #(ckend - below),%a3 194 movl %a3,%sp@(12) | address of ckend for later 195 | ---- switch off cache ---- 196 bra Lchoff | and to relocated below 197 198 199 below: movl %sp@+,%a3 | recover destination 200 movl %sp@+,%a1 | recover source 201 202 L1: movl %a1@-,%a3@- | copy kernel 203 subl #4,%d2 204 bne L1 205 206 | ---- switch off cache ---- 207 bra Lchoff | and to relocated ckend 208 209 above: movl %a1@+,%a3@+ 210 subl #4,%d2 211 bne above 212 213 lea %pc@(ckend:w),%a1 214 movl %a3,%sp@- 215 pea %pc@(_C_LABEL(startit_end):w) 216 L2: 217 movl %a1@+,%a3@+ 218 cmpl %sp@,%a1 219 bcs L2 220 addql #4,%sp 221 222 #if TESTONAMIGA 223 movew #0xFF0,0xdff180 | yellow 224 #endif 225 #if TESTONDRACO 226 moveb #0,0x200003c8 227 moveb #63,0x200003c9 228 moveb #63,0x200003c9 229 moveb #0,0x200003c9 230 #endif 231 232 | ---- switch off cache ---- 233 Lchoff: btst #3,%d5 234 jeq L3c 235 .word 0xf4f8 236 L3c: movl %d2,%sp@- | save %d2 237 movql #0,%d2 | switch off cache to ensure we use 238 movec %d2,%cacr | valid kernel data 239 movl %sp@+,%d2 | restore %d2 240 rts 241 242 | ---- copy kernel end ---- 243 244 ckend: 245 #if TESTONAMIGA 246 movew #0x0ff,0xdff180 | petrol 247 #endif 248 #if TESTONDRACO 249 moveb #0,0x200003c8 250 moveb #0,0x200003c9 251 moveb #63,0x200003c9 252 moveb #63,0x200003c9 253 #endif 254 255 movl %d5,%d2 256 roll #8,%d2 257 cmpb #0x7D,%d2 258 jne noDraCo 259 260 | DraCo: switch off MMU now: 261 262 subl %a5,%a5 263 .word 0x4e7b,0xd003 | movec %a5,tc 264 .word 0x4e7b,0xd806 | movec %a5,urp 265 .word 0x4e7b,0xd807 | movec %a5,srp 266 .word 0x4e7b,0xd004 | movec %a5,itt0 267 .word 0x4e7b,0xd005 | movec %a5,itt1 268 .word 0x4e7b,0xd006 | movec %a5,dtt0 269 .word 0x4e7b,0xd007 | movec %a5,dtt1 270 271 noDraCo: 272 moveq #0,%d2 | zero out unused registers 273 movel %d2,%a1 | (might make future compatibility 274 movel %d2,%a3 | would have known contents) 275 movel %d2,%a5 276 movel %a6,%sp | entry point into stack pointer 277 movel %d2,%a6 278 279 #if TESTONAMIGA 280 movew #0x0F0,0xdff180 | green 281 #endif 282 #if TESTONDRACO 283 moveb #0,0x200003c8 284 moveb #0,0x200003c9 285 moveb #63,0x200003c9 286 moveb #0,0x200003c9 287 #endif 288 289 jmp %sp@ | jump to kernel entry point 290 291 292 | A do-nothing MMU root pointer (includes the following long as well) 293 294 nullrp: .long 0x7fff0001 295 zero: .long 0 296 297 ENTRY_NOPROFILE(startit_end) 298
Indexes created Thu Oct 30 22:09:55 GMT 2025