; BOOTEASY, version 1.4. ; Developed from BOOTANY, with many imrovements. ; The main idea was to simplify the installation ; procedure and to remove unnecessary partition type switching. ; Second hard disk switching added. ; Author: Serge Vakulenko, F1_scancode equ 59 ; scancode of 'F1' key Enter_scancode equ 28 ; scancode of 'Enter' key Timeout equ 5 ; wait up to 5 seconds for reply StdBase equ 7c00h ; address where DOS loads us Base equ 600h ; address where we rewrite itself Partab equ 1beh ; partition table offset NumDisks equ 475h ; number of disk drives (BIOS data area) BootIndicator equ 0 ; partition record: boot indicator BeginHead equ 1 ; first partition sector: head number BeginSector equ 2 ; sector and cylinder SystemId equ 4 ; system type ; ------------------------------- dummy segment at 0 assume cs:dummy org Base ; address where we rewrite itself BaseEntry: org StdBase ; address where DOS loads us StdBaseEntry: dummy ends ; ------------------------------- code segment assume cs:code, ds:code, es:code, ss:code org 0 Boot: ; ; Setup the stack and segment registers ; xor AX,AX ; Zero register mov ES,AX ; ES := 0 mov DS,AX ; DS := 0 cli ; Disable interrupts mov SS,AX ; SS := 0 mov SP,StdBase ; SP at 7c00 sti ; Enable interrupts ; ; DOS loads this pgm at 0000:7C00. Any boot routine ; we call also expects to execute there so the first ; exercise is to move this code somewhere else. ; cld ; Clear direction mov SI,SP ; Copy from 7c00h... mov DI,Base ; ...to 600h... mov CX,256 ; ...512 bytes, or 256 words repne movsw ; Move itself to new location jmp FAR PTR BaseEntry+(Entry-Boot) ; ------------------------------- ; ; A valid function key was depressed (or defaulted) ; Attempt to boot the corresponding partition. ; Load: mov DX,BP ; restore drive number pop AX ; key '1'..'5' mov Base+default,AL ; save function key number cmp AL,'5' je SwitchDrive mov AH,16 mul AH ; AX = key * 16 add AX,Base+Partab-'1'*16 ; subtract '1' mov SI,AX ; ; Check if the partition is empty. ; test BYTE PTR SystemId[SI],0ffh je Menu ; Yes - display menu again mov BYTE PTR BootIndicator[SI],80h ; Mark partition as bootable call SaveBoot ; ; Read in and validate the partition's boot sector. ; mov DH,BeginHead[SI] ; head from partition table mov CX,BeginSector[SI] jmp loadboot ; ; Read in the boot sector from second disk. ; SwitchDrive: call SaveBoot mov CX,0001h ; cylinder 0, sector 1 xor DL,CL ; (DL ^= 1) switch drive loadboot: mov BX,StdBase ; ES already == 0 mov AX,0201h ; function, # of sectors int 13h ; read system boot record jc Menu ; exit if error cmp WORD PTR 510[BX],0aa55h ; test signature jne Menu ; reprompt if invalid ; ; Jump to secondary boot. ; DL now contains boot disk number (80h or 81h); ; ES:SI contains the address of partition table ; entry to boot. ; jmp FAR PTR StdBaseEntry ; ------------------------------- ; ; The main entry to the boot ; Entry: mov BP,DX ; DL contains current drive number inc DX ; 80h -> 81h, 81h -> 82h xor DL,80h+'3' ; 80h -> '2', 81h -> '1' mov Base+diskNum,DL ; ; Display the menu ; Menu: mov DI,Base+Partab ; set index mov CX,4 ; set loop count mov Base+key,'1' ; set key number in message xor DH,DH ; count of partitions menuloop: mov BYTE PTR BootIndicator[DI],CH ; Clear active flag mov AL,SystemId[DI] cmp AL,0 ; unused partition? je next cmp AL,5 ; extended DOS partition? je next inc DH ; increment partition count lea SI,Base+FkeyMsg ; get msg addr call Output lea SI,Base+nameTable-2 nameloop: inc SI inc SI mov BX,[SI] or BH,BH je endnameloop cmp BH,SystemId[DI] jne nameloop xor BH,BH endnameloop: lea SI,Base+namtab[BX] call Output next: add DI,16 ; next entry address inc Base+key loop menuloop cmp BYTE PTR DS:NumDisks,2 ; is the second disk present? je have2disks ; have disk 2 lea SI,Base+defaultMsg ; prepare 'Default' message or DH,DH ; no disk 2; do we have valid partitions? jne prompt ; several partitions, wait for reply int 18h ; no partitions, load ROM basic jmp Menu ; repeat, if no ROM basic have2disks: lea SI,Base+FkeyMsg ; print 'F5' call Output ; now SI points to "disk 2\nDefault..." prompt: call Output ; print 'Default' message reprompt: xor AH,AH ; GetTickCount int 1ah ; BiosTimerService mov BX,DX ; lo-order tick count add BX,192*Timeout/10 ; timeout value in ticks ; ; Get the reply ; waitkey: mov AH,1 ; keyboard status int 16h ; keybd bios service jnz reply ; jump if reply xor AH,AH ; GetTickCount int 1ah ; BiosTimerService cmp DX,BX ; check for timeout jb waitkey ; wait for scancode loaddefault: mov AL,Base+default ; prior system id jmp testkey ; boot default system reply: xor AH,AH ; read keyboard int 16h ; keybd bios service mov AL,AH ; Copy to AL cmp AL,Enter_scancode je loaddefault add AL,'1'-F1_scancode ; Turn into index testkey: cmp AL,'1' ; max Function key jb reprompt ; Invalid code check cmp AL,'5' ; max Function key jnbe reprompt ; if not F1..F5, branch push AX lea SI,Base+newLine ; new line lea BX,Base+Load push BX ; call Output; jmp Load ; ------------------------------- ; ; Output line [SI] to screen, end of line marked with 80h ; Output: cld ; reset direction flag lodsb ; load argument from string push AX ; save byte and AL,7fh ; insure valid character mov AH,14 ; write tty int 10h ; bios video service pop AX ; restore byte test AL,80h ; test for end of string jz Output ; do until end of string ret ; return to caller ; ------------------------------- ; ; Save boot block default partition settings ; SaveBoot: push SI mov AX,0301h ; write sector mov BX,Base ; ES already == 0 mov CX,0001h ; cylinder 0, sector 1 xor DH,DH ; drive #, head 0 int 13h ; replace boot record pop SI mov Base+default,'?' ; reset default ret ; ------------------------------- newLine db 13,10+80h FkeyMsg db 13,10,'F' key db '0 . . .',' '+80h,'disk ' diskNum db '1' defaultMsg db 13,10,10,'Default: F' default db '?',' '+80h nameTable db type01-namtab, 1 db type01-namtab, 4 db type01-namtab, 6 db type07-namtab, 7 db type08-namtab, 8 db type09-namtab, 9 db type0A-namtab, 0Ah db type63-namtab, 63h db type64-namtab, 64h db type64-namtab, 65h db type81-namtab, 80h db type81-namtab, 81h db type82-namtab, 82h db type93-namtab, 93h db typeA5-namtab, 0A5h db type9f-namtab, 09fh db type75-namtab, 75h db typedb-namtab, 52h db typedb-namtab, 0dbh db type40-namtab, 40h db typeF2-namtab, 0F2h db unknownPart-namtab, 0 namtab: type01 db 'do','s'+80h type07 db 'hpf','s'+80h type08 db 'fs ' type09 db 'ai','x'+80h type0A db 'os','2'+80h type63 db 'uni','x'+80h type64 db 'novel','l'+80h type81 db 'mini','x'+80h type82 db 'linu','x'+80h type93 db 'amoeb','a'+80h typeA5 db '386bs','d'+80h type9f db 'bsd','i'+80h type75 db 'pci','x'+80h typedb db 'cp','m'+80h type40 db 'veni','x'+80h typeF2 db 'dosse','c'+80h unknownPart db '?','?'+80h used equ $ - Boot db (1beh - used + 1) dup (0) ; error if code too big db 63 dup (0) ; clear rest of record dw 0aa55h ; magic code ends end