wok-tiny annotate memtest/stuff/bootloader.S @ rev 168

memtest: 386 support
author Pascal Bellard <pascal.bellard@slitaz.org>
date Fri Apr 30 16:35:54 2021 +0000 (2021-04-30)
parents
children aacd5b54d010
rev   line source
pascal@168 1 // Image/zImage & tiny bzImage linux kernel boot sector, (C) SliTaz, GPL2.
pascal@168 2
pascal@168 3 SYSSEG = 0x1000
pascal@168 4 setup_sects = 497
pascal@168 5 syssize = 500
pascal@168 6 cmd_line_ptr = 0x228
pascal@168 7
pascal@168 8 .text
pascal@168 9 .code16
pascal@168 10 .org 0
pascal@168 11 .globl _start
pascal@168 12 _start:
pascal@168 13
pascal@168 14 #define CODESZ 512 /* patched by installer */
pascal@168 15
pascal@168 16 // Default kernel format is 386 Image/zImage
pascal@168 17 //#define BZIMAGE 0x207 /* setup version ; for bzImage < 512 Kb only */
pascal@168 18 //#define ELKS /* 8086/286 linux port */
pascal@168 19
pascal@168 20 /* some extra features */
pascal@168 21 #define EXE_SUPPORT real mode dos .exe file support +208/264
pascal@168 22 #define CMDLINE dos kernel cmdline support +45
pascal@168 23 #define VCPI VCPI 4.0 support (386+) +109
pascal@168 24 #define SHUTDOWNDOS shutdown DOS services +29
pascal@168 25
pascal@168 26 /* some contraints to reduce the code size */
pascal@168 27 //#define FLOPPY_1440K_ONLY 1.44M floppies support only -26
pascal@168 28 //#define FLOPPY_HAS_2_SIDES hardcoded heads count to 2 -15
pascal@168 29 //#define NO_CMDLINE_SHRINK remove heading spaces ? -6-21
pascal@168 30 //#define NO_CMDLINE_FILE remove @cmdline file support ? -21
pascal@168 31 //#define NO_DOTS show progression dots ? -5
pascal@168 32 #ifndef BZIMAGE
pascal@168 33 //#define TINY_ZIMAGE system < 64Kb ? -11
pascal@168 34 //#define NO_MINSETUP default setup (dos only) ? -4
pascal@168 35 //#define NO_CURSOR_DEFINITION -8
pascal@168 36 #endif
pascal@168 37
pascal@168 38 #ifdef ELKS
pascal@168 39 .arch i8086
pascal@168 40 INITSEG = 0x0100
pascal@168 41 SETUPSEG = 0x0120
pascal@168 42 #define ONLY8086
pascal@168 43 #undef BZIMAGE
pascal@168 44 #undef VCPI
pascal@168 45 #else
pascal@168 46 INITSEG = 0x9000
pascal@168 47 SETUPSEG = 0x9020
pascal@168 48 #endif
pascal@168 49
pascal@168 50 .macro shlclw cnt,obj
pascal@168 51 #ifdef ONLY8086
pascal@168 52 movb \cnt,%cl
pascal@168 53 shlw %cl,\obj
pascal@168 54 #else
pascal@168 55 shlw \cnt,\obj
pascal@168 56 #endif
pascal@168 57 .endm
pascal@168 58
pascal@168 59 .macro shrclw cnt,obj
pascal@168 60 #ifdef ONLY8086
pascal@168 61 movb \cnt,%cl
pascal@168 62 shrw %cl,\obj
pascal@168 63 #else
pascal@168 64 shrw \cnt,\obj
pascal@168 65 #endif
pascal@168 66 .endm
pascal@168 67
pascal@168 68 #ifdef EXE_SUPPORT
pascal@168 69 #define EXEADRS(x) (x+0xE0)
pascal@168 70 #define FLAT20(x) (x+16*INITSEG)
pascal@168 71
pascal@168 72 .macro trace_int19
pascal@168 73 #ifdef ONLY8086
pascal@168 74 xorw %si, %si
pascal@168 75 movw %si, %ds
pascal@168 76 pushw 4+2(%si)
pascal@168 77 pushw 4(%si)
pascal@168 78 movw $step19, 4(%si)
pascal@168 79 movw $INITSEG, 4+2(%si)
pascal@168 80 #else
pascal@168 81 pushl $4
pascal@168 82 popw %si
pascal@168 83 popw %ds
pascal@168 84 pushl (%si)
pascal@168 85 movl $step19+(INITSEG<<16), (%si)
pascal@168 86 #endif
pascal@168 87 pushfw
pascal@168 88 popw %ax
pascal@168 89 incb %ah # set TF
pascal@168 90 pushw %ax
pascal@168 91 popfw
pascal@168 92 ljmp *4*0x19-4(%si)
pascal@168 93 .endm
pascal@168 94
pascal@168 95 stacktop = 0x9E00 # in 0x8000 .. 0xA000
pascal@168 96 decw %bp // Magic number: MZ
pascal@168 97 popw %dx
pascal@168 98 jmp start // Bytes on last page of file
pascal@168 99 .word (CODESZ+511)/512 // Pages in file INSTALLER
pascal@168 100 .word 0 // Relocations
pascal@168 101 .word (end_header-_start)/16 // Size of header in paragraphs
pascal@168 102 .word 4096 // Minimum extra paragraphs needed
pascal@168 103 .word -1 // Maximum extra paragraphs needed
pascal@168 104 .word (CODESZ+15)/16 // Initial (relative) SS value INSTALLER
pascal@168 105 .word stacktop // Initial SP value
pascal@168 106 .word 0 // Checksum INSTALLER?
pascal@168 107 .word EXEADRS(comstart) // Initial IP value
pascal@168 108 .word 0xFFF0 // Initial (relative) CS value
pascal@168 109 // .word 0x001C // File address of relocation table
pascal@168 110 // .word 0,0,0 // Overlay number
pascal@168 111 #else
pascal@168 112 #undef VCPI
pascal@168 113 #endif
pascal@168 114 start:
pascal@168 115 xorw %ax, %ax # %ax = 0
pascal@168 116 zeroed = 12 # zeroed registers
pascal@168 117 movw $zeroed/2, %cx # clear gdt + offset, %ds, limits
pascal@168 118 stacktop = 0x9E00 # in 0x8000 .. 0xA000 (+zeroed+12)
pascal@168 119 #ifdef ONLY8086
pascal@168 120 movw $INITSEG, %bx
pascal@168 121 #else
pascal@168 122 pushw $INITSEG
pascal@168 123 #endif
pascal@168 124 end_header:
pascal@168 125 cld # assume nothing
pascal@168 126 #if defined(BZIMAGE) && BZIMAGE >= 0x202
pascal@168 127 popw %es # %es contain INITSEG
pascal@168 128 movw %es, %di
pascal@168 129 #else
pascal@168 130 # cmdline offset at 0x22
pascal@168 131 movw $stacktop, %di # stacktop is an arbitrary value >=
pascal@168 132 # length of bootsect + length of
pascal@168 133 # setup + room for stack;
pascal@168 134 # 12 is disk parm size.
pascal@168 135 # ifdef ONLY8086
pascal@168 136 pushw %bx
pascal@168 137 # endif
pascal@168 138 popw %es # %es contain INITSEG
pascal@168 139 #endif
pascal@168 140 pushw %es
pascal@168 141 popw %ss # %es = %ss = INITSEG
pascal@168 142 movw %di, %sp # put stack at INITSEG:stacktop-...
pascal@168 143 #ifdef EXE_SUPPORT
pascal@168 144 cwd # force %dx = 0 (floppy only)
pascal@168 145 #endif
pascal@168 146
pascal@168 147 # Many BIOS's default disk parameter tables will not recognize
pascal@168 148 # multi-sector reads beyond the maximum sector number specified
pascal@168 149 # in the default diskette parameter tables - this may mean 7
pascal@168 150 # sectors in some cases.
pascal@168 151 #
pascal@168 152 # Since single sector reads are slow and out of the question,
pascal@168 153 # we must take care of this by creating new parameter tables
pascal@168 154 # (for the first disk) in RAM. We can set the maximum sector
pascal@168 155 # count to 36 - the most we will encounter on an ED 2.88.
pascal@168 156 #
pascal@168 157 # High doesn't hurt. Low does. Let's use the max: 63
pascal@168 158
pascal@168 159 rep # don't worry about cld
pascal@168 160 stosw # already done above
pascal@168 161 popw %bx # offset = 0
pascal@168 162 popw %ds # %ds = 0
pascal@168 163
pascal@168 164 movb setup_sects+0x7C00, %al # read bootsector + setup (%ds = 0)
pascal@168 165 incw %ax
pascal@168 166
pascal@168 167 ldsw 0x78(%bx), %si # %ds:%bx+0x78 is parameter table address
pascal@168 168 pushw %es
pascal@168 169 pushw %di
pascal@168 170 movb $6, %cl # copy 12 bytes
pascal@168 171 rep # don't worry about cld
pascal@168 172 movsw # already done above
pascal@168 173 movw %cx, %ds # %ds = 0
pascal@168 174 #ifdef ONLY8086
pascal@168 175 popw 0x78(%bx) # update parameter table address
pascal@168 176 popw 0x78+2(%bx)
pascal@168 177 #else
pascal@168 178 popl 0x78(%bx) # update parameter table address
pascal@168 179 #endif
pascal@168 180 pushw %ss
pascal@168 181 popw %ds # now %ds = %es = %ss = INITSEG
pascal@168 182 movb $63, 0x4-12(%di) # patch sector count, %di = stacktop
pascal@168 183
pascal@168 184 xchg %ax, %di # sector count
pascal@168 185 popw %ax # limits = 0
pascal@168 186 incw %cx # cylinder 0, sector 1, clear Z
pascal@168 187 call read_first_sectors # read setup
pascal@168 188
pascal@168 189 # This routine loads the system at address LOADSEG, making sure
pascal@168 190 # no 64kB boundaries are crossed. We try to load it as fast as
pascal@168 191 # possible, loading whole tracks whenever we can.
pascal@168 192
pascal@168 193 movw syssize, %di
pascal@168 194 decw %di
pascal@168 195 shrclw $9-4, %di
pascal@168 196 incw %di
pascal@168 197 movw $SYSSEG, %cx
pascal@168 198 #ifdef BZIMAGE
pascal@168 199 push %cx
pascal@168 200 #endif
pascal@168 201 call read_sectorsCX
pascal@168 202
pascal@168 203 # This procedure turns off the floppy drive motor, so
pascal@168 204 # that we enter the kernel in a known state, and
pascal@168 205 # don't have to worry about it later.
pascal@168 206
pascal@168 207 kill_motor:
pascal@168 208 xchgw %ax, %di # reset FDC (%di < 128)
pascal@168 209 int $0x13
pascal@168 210
pascal@168 211 # After that (everything loaded), we jump to the setup-routine
pascal@168 212 # loaded directly after the bootblock:
pascal@168 213 # Segments are as follows: %ds = %ss = INITSEG
pascal@168 214
pascal@168 215 #ifdef BZIMAGE
pascal@168 216 popw %bx
pascal@168 217 popw %si // SYSSEG:0
pascal@168 218 movesys: // %bx = DS, %si
pascal@168 219 movw $16, %ax
pascal@168 220 mulw %bx
pascal@168 221 addw %si, %ax
pascal@168 222 adcw $0x9300, %dx // %dx:%ax src flat address
pascal@168 223 movw $9, %cx
pascal@168 224 zero1:
pascal@168 225 pushw $0 // 2E..1E
pascal@168 226 loop zero1
pascal@168 227 //pushl $0x93100000 // 1A: dest
pascal@168 228 pushw $0x9310
pascal@168 229 pushw %cx
pascal@168 230 pushw $-1 // 18
pascal@168 231 pushw %cx // 16
pascal@168 232 pushw %dx // src
pascal@168 233 pushw %ax
pascal@168 234 pushw $-1 // 10
pascal@168 235 movb $8, %cl
pascal@168 236 movw %cx, %bx // will move 8*64 = 512Kb
pascal@168 237 zero2:
pascal@168 238 pushw $0 // 0E..00
pascal@168 239 loop zero2
pascal@168 240 movw %sp, %si
pascal@168 241 pushw %ss
pascal@168 242 popw %es
pascal@168 243 pushw %es
pascal@168 244 popw %ds
pascal@168 245 syslp:
pascal@168 246 movb $0x80, %ch
pascal@168 247 movb $0x87, %ah
pascal@168 248 int $0x15
pascal@168 249 incb 0x14(%si)
pascal@168 250 incb 0x1C(%si)
pascal@168 251 decw %bx
pascal@168 252 jne syslp
pascal@168 253 #endif
pascal@168 254 jmp_setup:
pascal@168 255 cli
pascal@168 256 ljmp $SETUPSEG, $0
pascal@168 257
pascal@168 258 #ifdef EXE_SUPPORT
pascal@168 259 #ifdef SHUTDOWNDOS
pascal@168 260 doiret:
pascal@168 261 iret
pascal@168 262 step19:
pascal@168 263 pushw %si
pascal@168 264 pushw %ds
pascal@168 265 movw %sp, %si
pascal@168 266 ldsw %ss:4(%si), %si
pascal@168 267 cmpw $0x19CD, (%si)
pascal@168 268 popw %ds
pascal@168 269 popw %si
pascal@168 270 jne doiret
pascal@168 271 xorw %si, %si
pascal@168 272 movw %si, %ds
pascal@168 273 pushw %cs
pascal@168 274 popw %ss
pascal@168 275 movw $stacktop-4-16, %sp
pascal@168 276 #ifdef ONLY8086
pascal@168 277 popw 4(%si)
pascal@168 278 popw 4+2(%si)
pascal@168 279 popw %bp
pascal@168 280 popw %di
pascal@168 281 popw %si
pascal@168 282 popw %dx
pascal@168 283 popw %cx
pascal@168 284 popw %bx
pascal@168 285 popw %ax
pascal@168 286 #else
pascal@168 287 popl 4(%si)
pascal@168 288 popaw
pascal@168 289 #endif
pascal@168 290 #ifdef BZIMAGE
pascal@168 291 jmp movesys
pascal@168 292 #endif
pascal@168 293 #endif
pascal@168 294 #ifndef BZIMAGE
pascal@168 295 movesys: // %ax = SYSSEG, %bx = DS, %si
pascal@168 296 shrclw $4, %si
pascal@168 297 addw %si, %bx
pascal@168 298 #ifdef TINY_ZIMAGE
pascal@168 299 movw $0xFFFF, %cx
pascal@168 300 xorw %si, %si
pascal@168 301 xorw %di, %di
pascal@168 302 cmpw %ax, %bx
pascal@168 303 jnc forward
pascal@168 304 decw %si
pascal@168 305 decw %di
pascal@168 306 std
pascal@168 307 forward:
pascal@168 308 movw %ax, %es
pascal@168 309 movw %bx, %ds
pascal@168 310 rep
pascal@168 311 movsb
pascal@168 312 cld
pascal@168 313 #else
pascal@168 314 subw %ax, %bx
pascal@168 315 jnc forward
pascal@168 316 movb $0x90, %ah
pascal@168 317 ;decw %ax
pascal@168 318 forward:
pascal@168 319 movw %ax, %es
pascal@168 320 movw %ax, %di
pascal@168 321 addw %bx, %di
pascal@168 322 movw %di, %ds
pascal@168 323 sbbw %di, %di // %di = 0 : -1
pascal@168 324 cmc // C = 1 : 0
pascal@168 325 adcw %di, %ax
pascal@168 326 xorw %si, %si
pascal@168 327 xorw %di, %di
pascal@168 328 movb $0x10, %cl
pascal@168 329 cmpb %cl, %ah // move 512k
pascal@168 330 rep
pascal@168 331 movsb
pascal@168 332 jns forward
pascal@168 333 #endif
pascal@168 334 #ifndef NO_CURSOR_DEFINITION
pascal@168 335 movb $1, %ah
pascal@168 336 movb $0, %bh
pascal@168 337 movb $0x20, %ch // 0x2000
pascal@168 338 int $0x10
pascal@168 339 #endif
pascal@168 340 pushw %ss
pascal@168 341 popw %ds
pascal@168 342 jmp jmp_setup
pascal@168 343 #endif
pascal@168 344 comstart:
pascal@168 345 cld # assume nothing
pascal@168 346 #ifdef ONLY8086
pascal@168 347 movw $INITSEG, %ax
pascal@168 348 pushw %ax
pascal@168 349 #else
pascal@168 350 pushw $INITSEG
pascal@168 351 #endif
pascal@168 352 popw %es
pascal@168 353 #ifdef CMDLINE
pascal@168 354 movw %sp, %di
pascal@168 355 movw $0x80, %si
pascal@168 356 lodsb
pascal@168 357 cbw
pascal@168 358 xchgw %ax, %cx
pascal@168 359 jcxz nocmdline
pascal@168 360 # if defined(BZIMAGE) && BZIMAGE >= 0x202
pascal@168 361 movw $INITSEG/16+stacktop/256, EXEADRS(cmd_line_ptr+1)
pascal@168 362 # else
pascal@168 363 movw $0xA33F, 0x7F(%si)
pascal@168 364 # endif
pascal@168 365 # ifndef NO_CMDLINE_SHRINK
pascal@168 366 skipspace:
pascal@168 367 lodsb
pascal@168 368 cmpb $0x20, %al
pascal@168 369 je skipspace
pascal@168 370 # ifndef NO_CMDLINE_FILE
pascal@168 371 movw %si,%dx
pascal@168 372 decw %si
pascal@168 373 subb $'@',%al
pascal@168 374 jne notafile
pascal@168 375 movb $0x3D,%ah
pascal@168 376 int $0x21
pascal@168 377 jc notafile
pascal@168 378 xchgw %ax,%bx
pascal@168 379 //movw %si,%dx // ~320 bytes max
pascal@168 380 movw $EXEADRS(notafile)-130,%cx
pascal@168 381 movb $0x3F,%ah
pascal@168 382 int $0x21
pascal@168 383 xchgw %ax,%cx
pascal@168 384 notafile:
pascal@168 385 # else
pascal@168 386 decw %si
pascal@168 387 # endif
pascal@168 388 # endif
pascal@168 389 rep
pascal@168 390 movsb
pascal@168 391 nocmdline:
pascal@168 392 orb EXEADRS(setup_sects), %ch
pascal@168 393 # ifndef NO_MINSETUP
pascal@168 394 # ifndef BZIMAGE
pascal@168 395 jnz setupok
pascal@168 396 mov $4, %ch
pascal@168 397 setupok:
pascal@168 398 # endif
pascal@168 399 # endif
pascal@168 400 #else
pascal@168 401 movb EXEADRS(setup_sects), %ch
pascal@168 402 #endif
pascal@168 403 movb $(512-(end_header-_start))/2, %cl
pascal@168 404 movw $0x100, %si
pascal@168 405 movw $end_header, %di
pascal@168 406 rep
pascal@168 407 movsw
pascal@168 408 movw $SYSSEG, %ax
pascal@168 409 movw %ds, %bx
pascal@168 410 pushw %es
pascal@168 411 popw %ss
pascal@168 412 #ifndef SHUTDOWNDOS
pascal@168 413 pushw %es
pascal@168 414 pushw $movesys
pascal@168 415 #endif
pascal@168 416 #ifdef VCPI
pascal@168 417 pushaw
pascal@168 418 smsww %ax
pascal@168 419 andb $1, %al
pascal@168 420 je isrm
pascal@168 421 movw $EXEADRS(gdt_vcpi),%si
pascal@168 422 movw $pagebuf-0x90000,%di // %es = 0x9000
pascal@168 423 movl $pagebuf+3,%es:0x1000(%di)
pascal@168 424 call_vcpi:
pascal@168 425 movb $0xDE,%ah // DE01, EBX = getiface(DS:SI, ES:DI)
pascal@168 426 int $0x67
pascal@168 427 movl $FLAT20(sw2pm_params),%esi
pascal@168 428 movb $0x0C,%al // DE0C switchpm(ESI)
pascal@168 429 jmp call_vcpi
pascal@168 430 pm_code:
pascal@168 431 movl %cr0,%eax
pascal@168 432 andl $0x7FFFFFFE,%eax
pascal@168 433 movl %eax,%cr0
pascal@168 434 movl %eax,%cr3
pascal@168 435 isrm:
pascal@168 436 # ifdef SHUTDOWNDOS
pascal@168 437 trace_int19
pascal@168 438 # else
pascal@168 439 lssw %cs:EXEADRS(saved_ss_sp),%sp
pascal@168 440 popaw
pascal@168 441 retf
pascal@168 442 # endif
pascal@168 443 #else
pascal@168 444 # ifdef SHUTDOWNDOS
pascal@168 445 # ifdef ONLY8086
pascal@168 446 pushw %ax
pascal@168 447 pushw %bx
pascal@168 448 pushw %cx
pascal@168 449 pushw %dx
pascal@168 450 pushw %si
pascal@168 451 pushw %di
pascal@168 452 pushw %bp
pascal@168 453 # else
pascal@168 454 pushaw
pascal@168 455 # endif
pascal@168 456 trace_int19
pascal@168 457 # endif
pascal@168 458 retf
pascal@168 459 #endif
pascal@168 460 #endif
pascal@168 461
pascal@168 462 # read_sectors reads %di sectors into %es:0 buffer.
pascal@168 463 # %es:0 is updated to the next memory location.
pascal@168 464 # First, sectors are read sector by sector until
pascal@168 465 # sector per track count is known. Then they are
pascal@168 466 # read track by track.
pascal@168 467 # Assume no error on first track.
pascal@168 468
pascal@168 469 #ifdef FLOPPY_1440K_ONLY
pascal@168 470 #ifndef FLOPPY_HAS_2_SIDES
pascal@168 471 #define FLOPPY_HAS_2_SIDES hardcore heads count to 2
pascal@168 472 #endif
pascal@168 473 #define FLOPPY_SECTORS 18 /* 18 sectors */
pascal@168 474 #else
pascal@168 475 #define FLOPPY_HEADS 2 /* 2 heads minimum */
pascal@168 476 #endif
pascal@168 477
pascal@168 478 return:
pascal@168 479 #ifndef NO_DOTS
pascal@168 480 movw $0xE2E,%ax
pascal@168 481 int $0x10
pascal@168 482 #endif
pascal@168 483 ret
pascal@168 484
pascal@168 485 check_limits:
pascal@168 486 #ifndef FLOPPY_1440K_ONLY
pascal@168 487 popw %dx
pascal@168 488 cmpb %al, %cl # max sector known ?
pascal@168 489 ja next_head # no -> store it
pascal@168 490 #ifndef FLOPPY_HAS_2_SIDES
pascal@168 491 #ifdef FLOPPY_HEADS
pascal@168 492 cmpb $FLOPPY_HEADS, %dh # 2 heads minimum
pascal@168 493 jb check_cylinder
pascal@168 494 #endif
pascal@168 495 cmpb %ah, %dh # max head known ?
pascal@168 496 ja next_cylinder # no -> store it
pascal@168 497 check_cylinder:
pascal@168 498 #endif
pascal@168 499 pushw %ax
pascal@168 500 cbw # %ah = 0
pascal@168 501 #else
pascal@168 502 pushw %dx
pascal@168 503 #endif
pascal@168 504 int $0x13 # reset controler
pascal@168 505 #ifndef FLOPPY_1440K_ONLY
pascal@168 506 popw %ax
pascal@168 507 movb $1, %al # sector by sector...
pascal@168 508 #else
pascal@168 509 movw $1, %ax
pascal@168 510 jmp more1trk
pascal@168 511 #endif
pascal@168 512 read_sectorslp:
pascal@168 513 pushw %dx # some bios break dx...
pascal@168 514 #ifndef FLOPPY_1440K_ONLY
pascal@168 515 pushw %ax # limits
pascal@168 516 subb %cl, %al # sectors remaining in track
pascal@168 517 ja tolastsect
pascal@168 518 movb $1, %al # first track sector by sector
pascal@168 519 tolastsect:
pascal@168 520 #else
pascal@168 521 movb $FLOPPY_SECTORS+1, %al
pascal@168 522 subb %cl, %al # sectors remaining in track
pascal@168 523 #endif
pascal@168 524 cbw
pascal@168 525 cmpw %di, %ax
pascal@168 526 jb more1trk
pascal@168 527 movw %di, %ax # sectors to read
pascal@168 528 more1trk:
pascal@168 529 pushw %ax # save context
pascal@168 530 movb $2, %ah # cmd: read chs
pascal@168 531 int $0x13
pascal@168 532 #ifndef FLOPPY_1440K_ONLY
pascal@168 533 popw %dx # save %ax
pascal@168 534 popw %ax # limits
pascal@168 535 #else
pascal@168 536 popw %ax # restore context
pascal@168 537 popw %dx
pascal@168 538 #endif
pascal@168 539 jc check_limits
pascal@168 540 #ifndef FLOPPY_1440K_ONLY
pascal@168 541 xchgw %ax, %bp
pascal@168 542 addw %dx,%cx # next sector
pascal@168 543 movw %cx, %si
pascal@168 544 pushw %dx
pascal@168 545 shlclw $5, %dx
pascal@168 546 movw %es, %cx
pascal@168 547 addw %dx, %cx
pascal@168 548 popw %dx
pascal@168 549 subw %dx,%di # update sector counter
pascal@168 550 popw %dx
pascal@168 551 #else
pascal@168 552 addw %ax,%cx # next sector
pascal@168 553 movw %cx, %si
pascal@168 554 pushw %ax
pascal@168 555 shlclw $5, %ax
pascal@168 556 movw %es, %cx
pascal@168 557 addw %ax, %cx
pascal@168 558 popw %ax
pascal@168 559 subw %ax,%di # update sector counter
pascal@168 560 #endif
pascal@168 561 read_sectorsCX:
pascal@168 562 movw %cx, %es # next location
pascal@168 563 jz return
pascal@168 564 read_sectors:
pascal@168 565 movw %si, %cx
pascal@168 566 #ifndef FLOPPY_1440K_ONLY
pascal@168 567 # al is last sector+1
pascal@168 568 # ah is last head+1
pascal@168 569 xchgw %ax, %bp
pascal@168 570 #endif
pascal@168 571 #ifndef FLOPPY_1440K_ONLY
pascal@168 572 cmpb %al,%cl # reach sector limit ?
pascal@168 573 jne bdendlp
pascal@168 574 next_head:
pascal@168 575 movb %cl,%al
pascal@168 576 #else
pascal@168 577 cmpb $FLOPPY_SECTORS+1,%cl # reach sector limit ?
pascal@168 578 jne bdendlp
pascal@168 579 #endif
pascal@168 580 movb $1,%cl # first sector
pascal@168 581 #ifndef FLOPPY_HAS_2_SIDES
pascal@168 582 incb %dh # next head
pascal@168 583 cmpb %ah, %dh # reach head limit ?
pascal@168 584 jne bdendlp
pascal@168 585 next_cylinder:
pascal@168 586 movb %dh,%ah
pascal@168 587 movb $0,%dh # first head
pascal@168 588 #else
pascal@168 589 xorb %cl,%dh # next head
pascal@168 590 jne bdendlp # reach head limit ?
pascal@168 591 #endif
pascal@168 592 # NOTE : support 256 cylinders max
pascal@168 593 incb %ch # next cylinder
pascal@168 594 read_first_sectors:
pascal@168 595 bdendlp:
pascal@168 596 jmp read_sectorslp
pascal@168 597
pascal@168 598 #ifdef VCPI
pascal@168 599 pagebuf = 0x98000
pascal@168 600 tss = gdt_abs-40
pascal@168 601 gdt = gdt_abs-32
pascal@168 602 gdt_null = gdt_abs-32
pascal@168 603 gdt_vcpi = gdt_abs-24
pascal@168 604 gdt_vcpi2 = gdt_abs-16
pascal@168 605 gdt_vcpi3 = gdt_abs-8
pascal@168 606 gdt_abs:
pascal@168 607 .word 0xFFFF
pascal@168 608 .long 0x92000000
pascal@168 609 .byte 0xCF,0
pascal@168 610 gdt_code:
pascal@168 611 .word 0xFFFF
pascal@168 612 gdt_code_base:
pascal@168 613 .long 0x9A000000+FLAT20(0)
pascal@168 614 .byte 0x8F,0
pascal@168 615 gdt_tss:
pascal@168 616 .word 0x00FF
pascal@168 617 gdt_tss_base:
pascal@168 618 .long 0x89000000+FLAT20(tss)
pascal@168 619 .byte 0,0
pascal@168 620 gdtr:
pascal@168 621 gdt_lim:
pascal@168 622 .word 0xFFFF
pascal@168 623 gdt_base:
pascal@168 624 .long FLAT20(gdt)
pascal@168 625 sw2pm_params:
pascal@168 626 sw2pm_cr3:
pascal@168 627 .long pagebuf+0x1000
pascal@168 628 sw2pm_gdtr_ptr:
pascal@168 629 .long FLAT20(gdtr)
pascal@168 630 sw2pm_idtr_ptr:
pascal@168 631 .long FLAT20(idtr)
pascal@168 632 sw2pm_ldtr:
pascal@168 633 .word 0
pascal@168 634 sw2pm_tr:
pascal@168 635 SEL_TSS = gdt_tss-gdt_null
pascal@168 636 .word SEL_TSS
pascal@168 637 sw2pm_jumpaddr:
pascal@168 638 .long pm_code
pascal@168 639 SEL_CODE = gdt_code-gdt_null
pascal@168 640 .word SEL_CODE
pascal@168 641 idtr:
pascal@168 642 idt_lim:
pascal@168 643 .word 0x03FF
pascal@168 644 idt_base:
pascal@168 645 .long 0
pascal@168 646 # ifndef SHUTDOWNDOS
pascal@168 647 saved_ss_sp:
pascal@168 648 .word stacktop-4-16-4,INITSEG
pascal@168 649 # endif
pascal@168 650 #endif
pascal@168 651 #ifdef ELKS
pascal@168 652 .org 0x1E3
pascal@168 653 .byte 13,10,7
pascal@168 654 .asciz "ELKS Boot"
pascal@168 655 #endif