1 ; **************************************************************************** 2 ; TRDOS386.ASM (TRDOS 386 Kernel) - v2.0.7 - trfdbs.s - FAT12 FD BOOT SECTOR 3 ; ---------------------------------------------------------------------------- 4 ; Last Update: 30/10/2023 (Previous: 12/08/2018) 5 ; ---------------------------------------------------------------------------- 6 ; Beginning: 25/01/2016 7 ; ---------------------------------------------------------------------------- 8 ; Assembler: NASM version 2.15 (trfdboot.s) 9 ; ---------------------------------------------------------------------------- 10 ; Turkish Rational DOS 11 ; Operating System Project v2.0 by ERDOGAN TAN (Beginning: 04/01/2016) 12 ; ---------------------------------------------------------------------------- 13 ; Modified from Retro DOS v4 FAT12 floppy disk boot sector source code 14 ; by Erdogan Tan. 'fdbs1440.s' (25/10/2023) 15 ; ---------------------------------------------------------------------------- 16 ; Derived from TRDOS Operating System v1.0 (8086) source code by Erdogan Tan 17 ; TRFDBOOT.ASM (31/07/2011) 18 ; **************************************************************************** 19 20 notvalidfmask equ 0018h 21 22 root_dir_buff equ 0700h 23 rts_segment equ 1000h 24 FAT_Buffer equ 0700h 25 26 ; 30/10/2023 27 root_FAT_buffer equ 0700h 28 29 [BITS 16] 30 [ORG 7C00h] 31 00000000 EB46 jmp short BS_01 32 00000002 90 nop 33 34 ; BootSector Identification (Data) Block 35 36 00000003 5452444F53322E30 bsOemName: db 'TRDOS2.0' 37 0000000B 0002 bsBytesPerSec: dw 512 38 0000000D 01 bsSecPerClust: db 1 39 0000000E 0100 bsResSectors: dw 1 40 00000010 02 bsFATs: db 2 41 00000011 E000 bsRootDirEnts: dw 224 42 00000013 400B bsSectors: dw 2880 43 00000015 F0 bsMedia: db 0F0h 44 00000016 0900 bsFATsecs: dw 9 45 00000018 1200 bsSecPerTrack: dw 18 46 0000001A 0200 bsHeads: dw 2 47 0000001C 0000 bsHidden1: dw 0 48 0000001E 0000 bsHidden2: dw 0 49 00000020 400B0000 bsHugeSectors: dd 2880 50 00000024 00 bsDriveNumber: db 0 51 00000025 00 bsReserved1: db 0 52 00000026 29 bsBpbSignature: db 29h 53 00000027 00000000 bsVolumeID: dd 0 54 0000002B 5452444F5320202020- bsVolumeLabel: db 'TRDOS ' 54 00000034 2020 55 00000036 4641543132202020 bsFileSysType: db 'FAT12 ' 56 0000003E 5254 bsReserved2: dw 'RT' 57 ; TRDOS 386 v2.0 2018 Extensions 58 00000040 2100 bsDataStart: dw 33 59 00000042 1300 bsRootDirStart: dw 19 60 00000044 0E00 bsRootDirSects: dw 14 61 ; 24/10/2023 - Retro DOS v4 62 00000046 1000 bsDirEntsPerSec: dw 16 63 64 BS_01: 65 00000048 8CC8 mov ax, cs 66 0000004A 8ED8 mov ds, ax 67 0000004C 8EC0 mov es, ax 68 69 0000004E FA cli 70 0000004F 8ED0 mov ss, ax 71 00000051 BCFEFF mov sp, 0FFFEh 72 00000054 FB sti 73 74 ; 24/10/2023 75 ;mov bp, sp 76 77 ; 25/10/2023 78 ; (DL = boot drive number -from INT 19h- 79 ; DL value is not changed in this boot sector code. 80 ; No need to save boot drive number.) 81 ; 82 ; overwrite fd drive number ! 83 ;mov [bsDriveNumber], dl ; drive number from INT 19h 84 ;BS_02: 85 00000055 A1[4200] mov ax, [bsRootDirStart] ; Root Dir Location 86 ; 24/10/2023 87 00000058 8B2E[4400] mov bp, [bsRootDirSects] 88 BS_02: 89 0000005C E88800 call fd_read_1 90 0000005F 7227 jc short BS_05 ; Disk read error message 91 92 ; 24/10/2023 93 ;;mov ax, 19 ; Root Dir Location 94 ;mov ax, [bsRootDirStart] 95 ;;mov cx, 14 ; Root Directory Sectors 96 ;mov cx, [bsRootDirSects] 97 ;mov bx, root_dir_buff ; Destination offset = 7E00h 98 ;mov si, bx 99 ;call fd_read 100 ;jc short BS_04 ; Disk read error message 101 102 ; 24/10/2023 103 ; ax = next root directory sector 104 105 ; 24/10/2023 106 ;mov bx, 224 107 ;mov bx, [bsRootDirEnts] ; Number of root dir entries 108 00000061 8B1E[4600] mov bx, [bsDirEntsPerSec] 109 00000065 BE0007 mov si, root_dir_buff 110 BS_03: 111 ; 24/10/2023 112 00000068 383C cmp byte [si], bh ; 0 113 ;cmp byte [si], 0 ; Is it null entry? 114 0000006A 7417 je short BS_04_ERR ; Jump if zero ( = ) 115 0000006C B90B00 mov cx, 11 ; Size of file/directory name 116 0000006F 56 push si 117 00000070 BF[F101] mov di, rtsfilename 118 00000073 F3A6 repe cmpsb ; Repeat if ZF = 1, CX > 0 119 ; Cmp byte DS:SI with ES:DI 120 00000075 5E pop si 121 00000076 741C je short BS_07 ; If the file name found 122 00000078 4B dec bx 123 00000079 7405 jz short BS_04 ; Jump if no next entry 124 0000007B 83C620 add si, 32 ; To next directory entry 125 0000007E EBE8 jmp short BS_03 ; Jump for next sector 126 BS_04: 127 ; 24/10/2023 128 ;dec word [bsRootDirSects] 129 ;jz short BS_04_ERR 130 ;inc word [bsRootDirStart] 131 ;jmp short BS_02 132 00000080 4D dec bp 133 00000081 75D9 jnz short BS_02 134 BS_04_ERR: 135 00000083 BE[9B01] mov si, Replace_Msg 136 00000086 EB03 jmp short BS_06 137 BS_05: 138 00000088 BE[9301] mov si, Error_Msg 139 BS_06: 140 0000008B E83E00 call print_msg 141 142 0000008E 31C0 xor ax, ax 143 00000090 CD16 int 16h ; BIOS Service func ( ah ) = 0 144 ; Read next kbd char 145 ; AH-scan code AL-char code 146 00000092 CD19 int 19h ; Reboot 147 148 BS_07: 149 ;mov al, [si+0Bh] ; Move attributes byte to BL 150 ;and al, notvalidfmask ; Is it a file, really? 151 ; 24/10/2023 152 00000094 F6440B18 test byte [si+0Bh], notvalidfmask 153 00000098 75E9 jnz short BS_04_ERR ; Jump if not 154 0000009A 8B441A mov ax, [si+1Ah] ; First cluster of the file 155 0000009D 83F802 cmp ax, 2 ; Start cluster 156 000000A0 72E6 jb short BS_05 157 158 ;mov [bsReserved2], ax ; Save the first cluster 159 ; 24/10/2023 160 000000A2 50 push ax 161 162 ; Load RTS (Kernel) file 163 000000A3 BE[CD01] mov si, Loading_Msg 164 000000A6 E82300 call print_msg 165 166 ; 24/10/2023 167 ;; Load FAT 168 ;;mov ax, 1 ; FAT Location 169 ;mov ax, [bsResSectors] 170 ;;mov cx, 9 ; FAT Sectors 171 ;mov cx, [bsFATsecs] 172 ;mov bx, FAT_Buffer 173 ;call fd_read 174 ;jc short BS_05 175 176 ; 24/10/2023 177 ;; Load RTS (Kernel) file 178 ;mov si, Loading_Msg 179 ;call print_msg 180 181 000000A9 58 pop ax 182 ;mov ax, [bsReserved2] ; The First cluster 183 000000AA BB0010 mov bx, rts_segment 184 000000AD 8EC3 mov es, bx 185 000000AF 31DB xor bx, bx 186 000000B1 E86C00 call load_file 187 000000B4 72D2 jc short BS_05 188 189 ; Launch RTS (Kernel) 190 000000B6 8CC0 mov ax, es 191 ;cli 192 000000B8 8ED0 mov ss, ax 193 ;mov sp, 0FFFEh 194 ;sti 195 ;mov dl, [bsDriveNumber] 196 000000BA B80010 mov ax, rts_segment ; 1000h 197 000000BD 8ED8 mov ds, ax 198 000000BF 8EC0 mov es, ax 199 200 000000C1 BD007C mov bp, 7C00h 201 202 000000C4 B8A101 mov ax, 417 203 204 000000C7 EA00000010 jmp rts_segment:0 205 206 ;db 0EAh 207 ;dw 0 208 ;dw rts_segment 209 210 print_msg: 211 BS_08: 212 000000CC AC lodsb ; Load byte at DS:SI to AL 213 000000CD 20C0 and al, al 214 000000CF 7415 jz short BS_10 ; If AL = 00h then stop 215 216 000000D1 B40E mov ah, 0Eh 217 000000D3 BB0700 mov bx, 07h 218 000000D6 CD10 int 10h ; BIOS Service func ( ah ) = 0Eh 219 ; Write char as TTY 220 ; AL-char BH-page BL-color 221 000000D8 EBF2 jmp short BS_08 222 223 BS_09: 224 ; 24/10/2023 225 000000DA FECD dec ch 226 ;dec byte [RetryCount] 227 000000DC 7408 jz short BS_10 ; cf = 1 228 229 ; 24/10/2023 230 ;; Reset disk system 231 ;push ax 232 ;xor ah, ah 233 ;;mov dl, [bsDriveNumber] 234 ;int 13h 235 ;pop ax 236 ;jnc short BS_12 237 238 ; 24/10/2023 239 000000DE 50 push ax 240 000000DF 31C0 xor ax, ax 241 ; ah = 0 ; INT 13h reset function 242 000000E1 CD13 int 13h 243 000000E3 58 pop ax 244 000000E4 7308 jnc short BS_11 245 BS_10: 246 000000E6 C3 retn 247 248 fd_read_1: 249 ; 24/10/2023 250 000000E7 B101 mov cl, 1 ; read 1 sector (only) 251 000000E9 BB0007 mov bx, root_FAT_buffer ; *-* ; 7E00h 252 fd_read_2: 253 ;fd_read: 254 ; Only for FAT12 Floppy Disks 255 256 ; 24/10/2023 257 000000EC B504 mov ch, 4 258 ;mov byte [RetryCount], 4 259 BS_11: 260 000000EE 51 push cx 261 000000EF 50 push ax ; PHYSICAL ADRESS CALCULATION 262 ;mov cl, 18 ; Sectors per track 263 000000F0 8A0E[1800] mov cl, [bsSecPerTrack] 264 000000F4 F6F1 div cl 265 000000F6 88E1 mov cl, ah ; Sector (zero based) 266 000000F8 FEC1 inc cl ; To make it 1 based 267 ;xor ah, ah 268 ;mov dl, 2 ; Heads 269 ;div dl 270 ; AL=cyl, AH=head, CL=sector 271 ;mov dh, ah 272 000000FA 28F6 sub dh, dh 273 000000FC D0E8 shr al, 1 274 000000FE 80D600 adc dh, 0 275 00000101 88C5 mov ch, al 276 277 ;mov dl, [bsDriveNumber] ; (!DL has not been changed!) 278 ; 24/10/2023 279 ; dl = [bsDriveNumber] 280 281 00000103 B80102 mov ax, 0201h 282 283 00000106 CD13 int 13h ; BIOS Service func ( ah ) = 2 284 ; Read disk sectors 285 ; AL-sec num CH-track CL-sec 286 ; DH-head DL-drive ES:BX-buffer 287 ; CF-flag AH-stat AL-sec read 288 00000108 58 pop ax 289 00000109 59 pop cx 290 0000010A 72CE jc short BS_09 291 0000010C 40 inc ax 292 293 ;add bx, 512 294 0000010D 80C702 add bh, 2 295 00000110 7309 jnc short BS_12 296 00000112 53 push bx 297 00000113 8CC3 mov bx, es 298 ;add bx, 1000h 299 00000115 80C710 add bh, 10h 300 00000118 8EC3 mov es, bx 301 0000011A 5B pop bx 302 BS_12: 303 ;dec cx 304 0000011B FEC9 dec cl 305 0000011D 75CD jnz short fd_read_2 ; 24/10/2023 306 0000011F C3 retn 307 308 load_file: 309 ; ES:BX = File Buffer 310 ; AX = First Cluster Number 311 ; Only for FAT12 Floppy Disks 312 313 ; 24/10/2023 314 ; bp = 0FFFEh (sp) 315 ; 24/10/2023 316 00000120 89E5 mov bp, sp ; 0FFFEh 317 BS_13: 318 ;mov [File_Cluster], ax 319 ; 24/10/2023 320 00000122 89C7 mov di, ax ; file (current) cluster 321 322 00000124 48 dec ax ; First cluster is cluster 2 323 00000125 48 dec ax 324 325 ;mov cx, 1 ; Sector count 326 327 00000126 8A0E[0D00] mov cl, [bsSecPerClust] 328 ; ch = 0 329 0000012A F6C102 test cl, 2 330 0000012D 7402 jz short BS_14 331 0000012F D1E0 shl ax, 1 332 333 ;add ax, 12 ; Beginning sector of Data 334 BS_14: 335 00000131 0306[4000] add ax, [bsDataStart] 336 ;call fd_read 337 ; 24/10/2023 338 00000135 E8B4FF call fd_read_2 339 00000138 7242 jc short BS_16 340 get_next_cluster: 341 ; 24/10/2023 342 ;push bx 343 ;mov ax, [File_Cluster] 344 ;mov bx, ax 345 ;; Multiply by 3 346 ;;mov dx, 3 347 ;;mul dx 348 ;add ax, ax 349 ;add ax, bx 350 351 ; 24/10/2023 352 0000013A 52 push dx 353 0000013B 31D2 xor dx, dx ; 0 354 0000013D 89F8 mov ax, di ; file (current) cluster 355 0000013F D1E8 shr ax, 1 ; Divide by 2 356 00000141 01F8 add ax, di ; AX * 1.5 = AX + AX/2 357 ; dx = 0 358 ; ax = byte offset in the FAT 359 00000143 F736[0B00] div word [bsBytesPerSec] 360 ; ax = FAT sector (index) number 361 ; dx = offset in FAT sector buffer 362 00000147 89D6 mov si, dx 363 00000149 5A pop dx 364 365 0000014A 39E8 cmp ax, bp ; previous FAT sector in the FAT buffer 366 0000014C 7405 je short SplitChk ; no need to read it again 367 0000014E E83100 call NextFATSec1 ; 25/10/2023 368 00000151 7229 jc short BS_16 369 SplitChk: 370 00000153 B9FF06 mov cx, FAT_Buffer-1 371 00000156 46 inc si 372 00000157 3B36[0B00] cmp si, [bsBytesPerSec] ; 512 ? 373 0000015B 750F jne short ClusterOk ; jb short ClusterOk 374 375 ; 24/10/2023 376 ; ax = next FAT sector (at 'fd_read' return) 377 378 ; 24/10/2023 379 0000015D 01CE add si, cx 380 ;lodsb 381 0000015F 8A34 mov dh, [si] 382 00000161 89CE mov si, cx 383 ;mov [si], al ; mov [7DFFh], al 384 00000163 8834 mov [si], dh 385 386 ; read next sector and then 387 ; use first byte of the next sector (as AH) 388 389 ; 24/10/2023 390 ;;mov ax, bp ; 2 byte opcode 391 ;xchg ax, bp ; 1 byte opcode 392 393 ; 25/10/2023 394 00000165 45 inc bp 395 396 00000166 E81F00 call NextFATSec2 ; 25/10/2023 397 00000169 7303 jnc short EvenOdd ; si = 7DFFh 398 0000016B C3 retn 399 ClusterOk: 400 ; si = 1 to 511 401 ; cx = FAT_Buffer-1 402 0000016C 01CE add si, cx 403 EvenOdd: 404 0000016E AD lodsw 405 406 ; di = current cluster 407 0000016F D1EF shr di, 1 408 00000171 730A jnc short BS_17 409 00000173 B104 mov cl, 4 410 00000175 D3E8 shr ax, cl 411 412 ; 24/10/2023 413 ;shr ax, 1 ; Divide by 2 414 ;xchg bx, ax 415 ;; BX = Buffer Byte Offset 416 ;; AX = Current Cluster 417 ;mov ax, [FAT_Buffer+bx] 418 ;jnc short BS_17 419 ;shr ax, 4 420 BS_15: 421 ; 24/10/2023 422 ;pop bx 423 424 00000177 3DF70F cmp ax, 0FF7h 425 0000017A 72A6 jb short BS_13 ; 25/10/2023 426 ; EOCC (kernel file has been loaded successfully) 427 BS_16: 428 0000017C C3 retn 429 BS_17: 430 0000017D 80E40F and ah, 0Fh 431 00000180 EBF5 jmp short BS_15 432 433 ; 24/10/2023 434 NextFATSec1: 435 00000182 89C5 mov bp, ax 436 ; 25/10/2023 437 00000184 0306[0E00] add ax, [bsResSectors] ; FAT sector LBA 438 NextFATSec2: 439 00000188 06 push es ; + ; kernel file buffer segment 440 00000189 53 push bx ; ++ ; save kernel file buffer address 441 442 0000018A 1E push ds 443 0000018B 07 pop es 444 445 ; 24/10/2023 ; *-* 446 ;mov bx, FAT_Buffer 447 448 ; 25/10/2023 449 ;add ax, [bsResSectors] ; FAT sector LBA 450 ;mov cl, 1 ; Read 1 FAT Sector 451 0000018C E858FF call fd_read_1 452 0000018F 5B pop bx ; ++ ; restore kernel file buffer address 453 00000190 07 pop es ; + ; kernel file buffer segment 454 455 00000191 C3 retn 456 457 ; 28/10/2023 458 00000192 00 db 0 459 Error_Msg: 460 00000193 0D0A db 0Dh, 0Ah 461 ;db 'TRDOS Kernel Loading Error!' 462 ; 24/10/2023 463 00000195 4572726F7221 db 'Error!' 464 465 0000019B 0D0A Replace_Msg: db 0Dh, 0Ah 466 0000019D 5265706C6163652074- db 'Replace the disk and press any key to reboot.' 466 000001A6 6865206469736B2061- 466 000001AF 6E6420707265737320- 466 000001B8 616E79206B65792074- 466 000001C1 6F207265626F6F742E 467 000001CA 0D0A00 db 0Dh, 0Ah,0 468 469 000001CD 0D0A Loading_Msg: db 0Dh, 0Ah 470 000001CF 4C6F6164696E67204B- db "Loading Kernel TRDOS386.SYS ..." 470 000001D8 65726E656C20545244- 470 000001E1 4F533338362E535953- 470 000001EA 202E2E2E 471 000001EE 0D0A00 db 0Dh, 0Ah, 0 472 473 rtsfilename: 474 000001F1 5452444F5333383653- db 'TRDOS386SYS' 474 000001FA 5953 475 000001FC 00 db 0 476 477 000001FD 00 times 510 - ($ - $$) db 0 478 479 000001FE 55AA bootsignature: db 55h, 0AAh