boot.S revision 1.2
1 | file: boot.s 2 | author: chapuni(GBA02750@niftyserve.or.jp) 3 | Yasha 4 | 5 | $NetBSD: boot.S,v 1.2 2001/09/27 14:08:27 minoura Exp $ 6 7 #include <machine/asm.h> 8 #include "iocscall.h" 9 10 #define BASEOFF 0x8000 11 #define BASEPTR_A (TEXTADDR+BASEOFF) 12 #define BASEPTR_R %pc@(top+BASEOFF:W) 13 14 #define SRAM 0x00ED0000 /* SRAM stat addr */ 15 #define SRAM_MEMSZ (SRAM + 8) /* (L) size of main memory */ 16 #define MINMEM 0x00400000 /* at least 4MB required */ 17 18 #define BOOT_ERROR(s) jbsr boot_error; .asciz s; .even 19 20 .globl _C_LABEL(bootufs) 21 .text 22 ASENTRY_NOPROFILE(start) 23 ASENTRY_NOPROFILE(top) 24 bras _ASM_LABEL(entry0) 25 .ascii "SHARP/" 26 .ascii "X680x0" 27 .word 0x8199,0x94e6,0x82ea,0x82bd 28 .word 0x8e9e,0x82c9,0x82cd,0x8cbb 29 .word 0x8ec0,0x93a6,0x94f0,0x8149 30 .word 0 31 | 0x2000 (FD), 0x2400 (SASI/SCSI) ( 0x0f0000) 32 | d4 SCSI ID 33 | jmp 34 ASENTRY_NOPROFILE(entry0) 35 moveml %d0-%d7/%a0-%a7,_C_LABEL(startregs) 36 lea BASEPTR_A:l,%a5 | set base ptr 37 #define _RELOC(adr) %a5@(((adr)-(BASEPTR_A&0xffff)):W) 38 #define ASRELOC(var) _RELOC(_ASM_LABEL(var)) 39 #define RELOC(var) _RELOC(_C_LABEL(var)) 40 41 lea RELOC(edata),%a1 42 bra _ASM_LABEL(entry) 43 44 | Disklabel= 404bytes 45 | Since LABELLOFFSET in <machine/disklabel.h> is 0x40, 46 | entry must be after 0x000001d4 (0x000f01d4) 47 disklabel: 48 .space 406 49 50 ASENTRY_NOPROFILE(entry) 51 movew #_end-1,%d0 | bss end (low word only) 52 53 | clear out bss (must be <= 64KB) 54 subw %a1,%d0 55 clrbss: clrb %a1@+ 56 dbra %d0,clrbss 57 58 movel %d4,RELOC(ID) | SCSI ID (if booted from SCSI) 59 60 | set system stack 61 lea ASRELOC(top),%a1 | set stack pointer to 0x000F0000 62 lea %a1@,%sp | a1 will be used later for IOCS calls 63 64 | we use 68020 instructions, and check MPU beforehand 65 | 66 | here d1.w = -1, and the above "subw a1,d0" = 0x9049, and 67 | if MPU <= 010 loads 0x49, 68 | if MPU >= 020 loads 0x90. 69 | This is a move, not a tst instruction 70 | because pc-relative tsts are not availble on 000/010. 71 chkmpu: moveb %pc@(clrbss-chkmpu-2:B,%d0:W:2),%d0 | 103B 02xx 72 jmi mpuok | MC68020 or later 73 BOOT_ERROR("MPU 68000?") 74 mpuok: | XXX check for MMU? 75 76 IOCS(__BOOTINF) 77 lsll #8,%d0 | clear MSByte 78 lsrl #8,%d0 | 79 movel %d0,RELOC(BOOT_INFO) 80 81 | 82 | 0x80...0x8F SASI 83 | 0x90...0x93 Floppy 84 | 0xED0000...0xED3FFE SRAM 85 | others ROM (SCSI?) 86 | 87 movel %d0,%d1 88 clrb %d1 89 tstl %d1 90 jne boot_ram_rom 91 | 92 | SASI or Floppy 93 | 94 movel %d0,%d2 95 andib #0xFC,%d0 96 cmpib #0x90,%d0 97 jne boot_dev_unsupported | boot from SASI? 98 | 99 | Floppy 100 | 101 moveb %d2,%d0 102 andib #0x03,%d0 | drive # (head=0) 103 jbsr check_fd_format 104 moveml %d0-%d1,RELOC(FDSECMINMAX) | min and max sec # 105 lslw #8,%d2 106 moveq #0x70,%d1 107 orw %d2,%d1 | PDA*256 + MODE 108 movel %d1,RELOC(FDMODE) 109 movel %d0,%d2 | read position (first sector) 110 movel #8192,%d3 | read bytes 111 IOCS(__B_READ) 112 jra boot_read_done 113 114 #include "chkfmt.s" 115 116 boot_ram_rom: 117 movel %d0,%d1 118 swap %d1 119 cmpiw #0x00ED,%d1 120 jne boot_SCSI 121 | boot from SRAM? 122 123 boot_dev_unsupported: 124 BOOT_ERROR("unsupported boot device") 125 126 | 127 | volatile void BOOT_ERROR(const char *msg); 128 | print error message, wait for key press and reboot 129 | 130 booterr_msg: .ascii "\r\n\n" 131 .ascii BOOT 132 .asciz ": " 133 reboot_msg: .asciz "\r\n[Hit key to reboot]" 134 .even 135 136 ENTRY_NOPROFILE(BOOT_ERROR) 137 addql #4,%sp 138 139 boot_error: lea %pc@(booterr_msg),%a1 140 IOCS(__B_PRINT) 141 moveal %sp@+,%a1 142 IOCS(__B_PRINT) 143 lea %pc@(reboot_msg),%a1 144 IOCS(__B_PRINT) 145 146 | wait for a key press (or release of a modifier) 147 IOCS(__B_KEYINP) 148 149 | issue software reset 150 trap #10 151 | NOTREACHED 152 153 154 | 155 | ROM boot ... probably from SCSI 156 | 157 boot_SCSI: 158 #ifdef SCSI_ADHOC_BOOTPART 159 | 160 | Find out boot partition in an ad hoc manner. 161 | 162 163 | get block length of the SCSI disk 164 SCSIIOCS(__S_READCAP) | using buffer at a1 165 tstl %d0 166 jeq 1f 167 BOOT_ERROR("READCAP failed") 168 1: moveq #0,%d5 169 moveb %a1@(6),%d5 | 1: 256, 2: 512, 4: 1024 170 lsrb #1,%d5 | 0: 256, 1: 512, 2: 1024 171 movel %d5,RELOC(SCSI_BLKLEN) 172 173 | find out the start position of the boot partition 174 | XXX VERY AD HOC 175 | 176 | ROM firmware: 177 | pass read pos (in block #) in d2 178 | SCSI IPLs (genuine and SxSI): 179 | pass read pos (in kilobytes) in d2 180 | partition table on the memory is destroyed 181 | BOOT MENU Ver.2.22: 182 | passes partition table entry address in a0 183 | d2 is cleared to zero 184 | No other IPL is supported. XXX FIXME 185 tstl %d2 186 jne sc1 187 | no information in d2 -- probably from BOOT MENU 188 | a0 points the partiion table entry 189 movel %a0@(0x0008),%d2 | in KByte 190 sc1: cmpl #0x20,%d2 191 jcs sc2 192 lsll #8,%d2 | clear MSByte 193 lsrl #6,%d2 | 194 lsrl %d5,%d2 | in sector 195 sc2: movel %d2,RELOC(SCSI_PARTTOP) 196 197 | read entire boot 198 moveq #8192/256,%d3 | size is 8KB 199 lsrl %d5,%d3 | in sector 200 jbsr scsiread | read at %a1 201 #else 202 moveq #1,%d5 | 512bytes/sec 203 movel %d5,%sp@- 204 moveq #8192/512,%d3 | 205 moveq #0x40,%d2 | (sd*a ) 206 SCSIIOCS(__S_READ) 207 #endif 208 209 boot_read_done: 210 jmp first_kbyte 211 212 read_error: BOOT_ERROR("read error") 213 214 #undef RELOC /* base register a5 is no longer available */ 215 #undef ASRELOC 216 #undef _RELOC 217 218 | 219 | read SCSI 220 | 221 | input: d2.l: pos in sector 222 | d3.l: len in sector 223 | d4: target SCSI ID 224 | d5: sector length (0: 256, 1: 512, 2: 1024) 225 | a1: buffer address 226 | destroy: 227 | d0, d1, a1 228 | 229 scsiread: 230 moveml %d2-%d3/%d6-%d7/%a2,%sp@- 231 | if (pos >= 0x200000 || (len > 255 && pos + len >= 0x200000)) 232 | use READEXT 233 | else 234 | use READ 235 moveq #0x20,%d0 236 swap %d0 | d0.l = 0x00200000 237 moveq #0,%d6 238 subqb #1,%d6 | d6.l = 255 239 moveq #8,%d7 240 addb %d5,%d7 | d7.b = (sector length: 0-2) + 8 241 cmpl %d0,%d2 242 jcc scsiread_ext 243 moveq #__S_READ,%d1 244 cmpl %d3,%d6 245 jcc scsiread_noext 246 subl %d2,%d0 | d0.0 = 0x200000 - pos 247 cmpl %d0,%d3 | <= len 248 jcs scsiread_noext | no 249 250 scsiread_ext: | use READEXT 251 extw %d6 | d6.l = 65535 252 moveq #__S_READEXT,%d1 253 254 scsiread_noext: | use READ 255 loop_scsiread: 256 | d1: SCSI IOCS call # 257 | d6: max sector count at a time 258 movel %d3,%a2 | save original len in a2 259 cmpl %d3,%d6 260 jcc 1f 261 movel %d6,%d3 262 1: IOCS(__SCSIDRV) | SCSIIOCS(d1) 263 tstl %d0 264 jne read_error 265 movel %d3,%d0 | addr += read count << (8 + sec len) 266 asll %d7,%d0 267 addl %d0,%a1 268 exg %d3,%a2 | restore original len to d3 269 addl %a2,%d2 | pos += read count 270 subl %a2,%d3 | len -= read count 271 jne loop_scsiread 272 moveml %sp@+,%d2-%d3/%d6-%d7/%a2 273 rts 274 275 | 276 | The former part must reside in the first 1KB. 277 | 278 .globl first_kbyte 279 first_kbyte: 280 |-------------------------------------------------------------------------- 281 | 282 | The latter text+data part is not accessible at the first boot time. 283 | PC-relative can be used from here. 284 | 285 jmp _C_LABEL(bootufs) | 0x0Fxxxx 286 287 .word 0 288 289 | int badbaddr __P((caddr_t adr)); 290 | check if the given address is valid for byte read 291 | return: 0: valid, 1: not valid 292 293 ENTRY_NOPROFILE(badbaddr) 294 lea 0x0008:W,%a1 | MPU Bus Error vector 295 moveq #1,%d0 296 lea %pc@(badr1),%a0 297 movew %sr,%sp@- 298 oriw #0x0700,%sr | keep out interrupts 299 movel %a1@,%sp@- 300 movel %a0,%a1@ | set bus error vector 301 movel %sp,%d1 | save sp 302 moveal %sp@(10),%a0 303 tstb %a0@ | try read... 304 moveq #0,%d0 | this is skipped on bus error 305 badr1: moveal %d1,%sp | restore sp 306 movel %sp@+,%a1@ 307 movew %sp@+,%sr 308 rts 309 310 | void RAW_READ __P((void *buf, u_int32_t blkpos, size_t bytelen)); 311 | inputs: 312 | buf: input buffer address 313 | blkpos: read start position in the partition in 512byte-blocks 314 | bytelen: read length in bytes 315 316 Lraw_read_buf=4+(4*11) 317 Lraw_read_pos_=Lraw_read_buf+4 318 Lraw_read_len=Lraw_read_buf+8 319 320 #ifdef SCSI_ADHOC_BOOTPART 321 | RAW_READ of physical disk 322 ENTRY_NOPROFILE(RAW_READ0) 323 moveq #0,%d0 324 jra raw_read1 325 #endif 326 327 ENTRY_NOPROFILE(RAW_READ) 328 #ifdef SCSI_ADHOC_BOOTPART 329 movel _C_LABEL(SCSI_PARTTOP),%d0 330 raw_read1: 331 #endif 332 moveml %d2-%d7/%a2-%a6,%sp@- 333 moveml %sp@(Lraw_read_buf),%d1-%d3 334 movel %d1,%a1 335 | d2.l: pos in 512byte-blocks 336 | d3.l: length in bytes 337 | a1 (=d1): buffer address 338 339 lea BASEPTR_R,%a5 | set base ptr 340 #define _RELOC(adr) %a5@(((adr)-(BASEPTR_A&0xffff)):W) 341 #define ASRELOC(var) _RELOC(_ASM_LABEL(var)) 342 #define RELOC(var) _RELOC(_C_LABEL(var)) 343 344 tstb _RELOC(_C_LABEL(BOOT_INFO)+1) | simple check. may be incorrect! 345 beqs raw_read_floppy 346 347 raw_read_scsi: 348 movel RELOC(ID),%d4 | SCSI ID 349 #ifdef SCSI_ADHOC_BOOTPART 350 movel RELOC(SCSI_BLKLEN),%d5 | sector size: 0-2 351 | XXX length must be sector aligned 352 lsrl #8,%d3 | size in 256byte-blocks 353 lsrl %d5,%d3 | size in sector 354 bcss read_half | minimal error check 355 lsll #1,%d2 | X flag and d2: pos in 256byte-blocks 356 roxrl %d5,%d2 | pos in sector 357 addl %d0,%d2 | physical pos in sector 358 #else 359 moveq #1,%d5 | 512bytes/sec 360 moveq #9,%d0 | shift count 361 addl #511,%d3 362 lsrl %d0,%d3 363 bcss read_half | minimal error check 364 365 addl #0x40,%d2 | 'a' partition starts here 366 #endif 367 | jcc 1f 368 | BOOT_ERROR("out of seek") | pos exceeds 32bit 369 |1: 370 jbsr scsiread 371 bras raw_read_end 372 373 raw_read_floppy: 374 | 375 | Floppy read routine 376 | 377 378 | convert to seek position 379 380 asll #2,%d2 | size in 128byte-blocks 381 382 | sec = raw_read_pos (d2) 383 | sec >>= 7 + (sector length: 0-3) 384 385 lea RELOC(FDSECMINMAX),%a0 386 moveq #0,%d1 387 moveb %a0@,%d1 | d1: sector length (0-3) 388 lsrl %d1,%d2 | d2: pos in sector 389 bcss read_half | error check 390 391 | trk = sec / (# sectors) 392 | sec = sec % (# sectors) 393 394 moveb %a0@(7),%d1 | d1: max sector # 395 subb %a0@(3),%d1 | - min sector # 396 addqb #1,%d1 | d1: # sectors 397 divu %d1,%d2 | d2: (sec << 16) | track 398 399 | position = (sec length << 24) | (track/2 << 16) 400 | | (track%2 << 8) | (min sec # + sec) 401 402 movel %a0@,%d0 | d0: (sec len << 24) | min sec # 403 lsrw #1,%d2 | d2: (sec << 16) | (track / 2) 404 jcc 1f 405 bset #8,%d0 | |= (track % 2) << 8 406 1: swap %d2 | d2: ((track / 2) << 16) | sec 407 addl %d0,%d2 | d2: position 408 409 | read 410 movel RELOC(FDMODE),%d1 | PDA*256 + MODE 411 412 | B_READ (for floppy) 413 | d1.w: PDA x 256 + MODE 414 | PDA: 0x90 (drive 0) ... 0x93 (drive 3) 415 | MODE: bit6: MFM 416 | bit5: retry 417 | bit4: seek 418 | d2.l: position 419 | bit31-24: sector length (0: 128, 1: 256, 2: 512, 3: 1K) 420 | bit23-16: track # (0-79) 421 | bit15-08: side (0 or 1) 422 | bit07-00: sector # (1-) 423 | d3.l: read bytes 424 | a1: read address 425 | return: 426 | d0: bit 31-24 ST0 427 | bit 23-16 ST1 428 | bit 15- 8 ST2 429 | bit 7- 0 C 430 | -1 on parameter error 431 | destroy: d0, d2, d3, a1 432 IOCS(__B_READ) 433 andil #0xf8ffff00,%d0 | check status (must be zero) 434 jne read_error 435 436 raw_read_end: 437 moveml %sp@+,%a2-%a6/%d2-%d7 438 rts 439 #undef _RELOC /* base register a5 is no longer available */ 440 #undef ASRELOC 441 #undef RELOC 442 443 read_half: BOOT_ERROR("read half of block") 444 445 446 ENTRY_NOPROFILE(B_KEYINP) 447 IOCS(__B_KEYINP) 448 rts 449 450 ENTRY_NOPROFILE(B_PUTC) 451 movel %sp@(4),%d1 452 IOCS(__B_PUTC) 453 rts 454 455 ENTRY_NOPROFILE(B_PRINT) 456 movel %sp@(4),%a1 457 IOCS(__B_PRINT) 458 rts 459 460 | 461 | void memcpy(void *dst, const void *src, size_t count); 462 | void memmove(void *dst, const void *src, size_t count); 463 | 464 | small and slow memcpy... 465 | THIS FUNCTION DOES NOT CONFORM THE ANSI STANDARD 466 | 467 ENTRY_NOPROFILE(memcpy) 468 ENTRY_NOPROFILE(memmove) 469 lea %sp@(12),%a1 470 movel %a1@,%d1 | count 471 jeq Lmcpret 472 moveal %a1@-,%a0 | src 473 moveal %a1@-,%a1 | dest 474 cmpl %a1,%a0 475 jcc Lmcpfw 476 | copy backward 477 addal %d1,%a0 478 addal %d1,%a1 479 1: moveb %a0@-,%a1@- 480 subql #1,%d1 481 jne 1b 482 jra Lmcpret 483 Lmcpfw: | copy forward 484 1: moveb %a0@+,%a1@+ 485 subql #1,%d1 486 jne 1b 487 Lmcpret: 488 | movel %sp@(8),%d0 | uncomment this to conform ANSI 489 rts 490 491 492 | 493 | global variables 494 | 495 BSS(ID, 4) | SCSI ID 496 BSS(BOOT_INFO, 4) | result of IOCS(__BOOTINF) 497 BSS(FDMODE, 4) | Floppy access mode: PDA x 256 + MODE 498 BSS(FDSECMINMAX, 8) | +0: (min sector) sector length 499 | +1: (min sector) track # 500 | +2: (min sector) side 501 | +3: (min sector) sector # 502 | +4: (max sector) sector length 503 | +5: (max sector) track # 504 | +6: (max sector) side 505 | +7: (max sector) sector # 506 #ifdef SCSI_ADHOC_BOOTPART 507 BSS(SCSI_PARTTOP, 4) | start sector of boot partition 508 BSS(SCSI_BLKLEN ,4) | sector len 0: 256, 1: 512, 2: 1024 509 #endif 510
Indexes created Wed Oct 01 15:09:59 GMT 2025