;install.asm ;jeff leyda ;9/8/97 ; ;installation program for floppy disk boot emulator (aka flopper) ;compiled with tasm/tlink ;portions of the boot-through bootsector code (c) 1992, Urmas Rahu ; ; ;Modified 10/9/99 ; Changed install to copy the original bootsector to the outer ; portion of the diskette, so that after the vector table is saved, the ; original bootsector is restored so the disk doesn't have to be reformatted. cseg segment assume cs: cseg,ds:cseg,es:cseg,ss:cseg org 100h main: jmp go ;---------------------------------------------------------------------------- ;variables and data ;---------------------------------------------------------------------------- SECSIZE equ 512 ; standard sector size MAGIC equ 42 ; the answer to life, universe ; and everything vectortbl db "vectable.dat",0 ;file to store vector table in ;**************************************************************************** bootsector: jmp short bootcode ; boot sector starts here nop bootdata db 1bH dup (?) ; near jump to boot code oldsectorcx dw ? ; cx,dx values of where the oldsectordx dw ? ; original sector is stored hdload: mov ax, 0201H ; this part of code will be mov bx, 07c0H ; copied to 07c0:0200, just mov es, bx ; above the boot sector image, xor bx, bx ; so that the hard disk boot mov cx, 0001H ; sector will fit right below mov dx, 0080H ; it. int 13H ; read hard drive's boot record db 0e9H ; jump to hard disk boot code dw -SECSIZE - (hdload_end-hdload) ; (at 07c0:0000) hdload_end label byte bootcode: ; start of my boot code ; grab old boot sector and replace this one. mov ax, 0201h mov si, 7c1eh ; we know we booted to 0:7c00 ; mov bx, es:[si] mov cx, bx add si, 2 mov bx, es:[si] mov dx, bx mov bx, 07c0h int 13h ; read last sector push cx push dx mov ax, 0301h ; write it as 1st sector mov cx, 1 mov dx, 0 int 13h pop dx pop cx mov bx,40h ; set a flag at 40:f0h mov es,bx ; so install knows that mov bx,0f0h ; the vector table has been mov byte ptr es:[bx],MAGIC ; saved. mov bx,0 ; write vector table info mov es,bx ; to last 2 sectors on disk. mov ax,0302h ; sub cx,1 ; ; mov dx,0 ; int 13h ; mov bx, 07c0H mov ds, bx ; set segment regs to 07c0 mov es, bx mov bx, message - bootsector mov ah, 0eH dispmsg: mov al, [bx] ; show message of bypassing cmp al, 0 jz copycode int 10H ; write teletype inc bx jmp dispmsg copycode: xor ax,ax ; wait for a keypress int 16h mov si, hdload - bootsector ; copy the hard disk boot sector mov di, SECSIZE ; loader to 07c0:0200 mov cx, bootcode - hdload cld rep movsb db 0e9H ; jump to hard disk boot sector dw SECSIZE - (copycode_end - bootsector) ; loader copycode_end label byte ; (at 07c0:0200) message db 13,"Interrupt vector table saved.",10,13 db "The computer will now continue booting to the C: drive." db 10,13,10,13,"Please re-run the install.com program after booting." db 10,13,10,13,"Press any key to continue...",10,13,0 filler db SECSIZE - (filler-bootsector) dup (' ') old_bootdata: db 1eH dup (?) ; old boot sector will be old_bootcode: db (512-1eH) dup (?) ; read here ;**************************************************************************** welcomemsg db "Welcome to Flopper, the diskette boot emulator. " db "컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� " db " " db "Once installed, this program will allow you to " db "play many games from the early 1980's that were " db "released as a self booting 360k floppy disks. " db " " db "This program emulates a floppy diskette bootup " db "under DOS from a disk image file on your drive. " db " " db " " db "Press ENTER to continue installation " db "or ESC to quit " db -1 step1 db "Requirements: " db "컴컴컴컴컴컴� " db " " db "Flopper requires the following hardware: " db " � 386 or higher CPU " db " � at least 2mb of memory " db " � 1 floppy drive (hard drive preferred) " db " � DOS 2.1 or higher " db " � diskette images " db " " db " " db "Press ENTER to continue installation " db "or ESC to quit " db -1 step2 db "Requirements, page 2: " db "컴컴컴컴컴컴컴컴컴컴� " db "This program installation will require a blank, " db "formatted floppy diskette for A: drive of this " db "computer. Flopper needs some information from " db "your computer which is only available during " db "boot BEFORE the operating system loads, so we " db "need to make a special boot diskette. " db " " db "You will not need this disk after installation. " db " " db "Press ENTER to continue installation " db "or ESC to quit " db -1 step3 db "Insert floppy diskette now " db "컴컴컴컴컴컴컴컴컴컴컴컴컴 " db " " db "This program is about to create a specialized " db "bootup disk, which will gather some information " db "about the computer at its booting stage. " db " " db "Once this disk has been created, the computer " db "will then reboot to the bootup disk. " db " " db " " db "Insert a formatted disk into drive A: now and " db "press ENTER. Or press ESC to quit. " db -1 step4 db "Time to reboot... " db "컴컴컴컴컴컴컴컴� " db " " db "The computer will now reboot. " db " " db "If you are running this program in a DOS shell " db "under windows, you should press ESC now, exit " db "windows, then reboot to this floppy diskette. " db " " db "Follow the directions on the screen after you " db "have booted to this diskette. " db " " db "Press ENTER to continue reboot or ESC to quit. " db -1 endingmsg db "Welcome back. " db "컴컴컴컴컴컴� " db " " db "Now that the vital bootup information has been " db "gathered from your computer, the final step in " db "this installation process is to save the data " db "to a file. " db " " db "Make sure the floppy disk is still in the drive." db " " db " " db " " db "Press ENTER to continue or ESC to quit. " db -1 finished db "All Done! " db "컴컴컴컴� " db " " db "Flopper is ready for use. You no longer need " db "the floppy diskette, please remove it from the " db "drive. " db " " db " " db " " db "To play a game, simply type FLOPPER " db "where filename is a valid diskette image. " db " " db "Press any key to quit. " db -1 floperror db "Floppy disk read/write error! " db "컴컴컴컴컴컴컴컴컴컴컴컴컴컴� " db " " db "The floppy disk in drive A: is either not " db "inserted into the drive or is not formatted. " db " " db "Please check the drive or replace the diskeete. " db " " db " " db " " db " " db "Press ENTER to continue or ESC to quit. " db " " db -1 draw_line proc ;DX=row,col ;cx=count ;bl=color ;al=character dec dh push cx call pos_cursor mov ah,9 mov bh,0 int 10h pop cx dec si cmp si,0 jnz draw_line ret draw_line endp pos_cursor proc ;positions cursor at DX (row,col) mov ah,2 mov bh,0 int 10h ret pos_cursor endp dotext proc text_len = 48 mov dh,12 mov bx,17h ; default to blue unless carry flag is set jnc disp_text mov bx,47h ; red text disp_text: mov ax,1300h mov cx,text_len mov dl,16 int 10h add bp,text_len inc dh cmp byte ptr es:[bp],-1 jnz disp_text ret dotext endp anykey proc ;wait for a keypress. If it's ENTER, keep going, ESC, set carry xor ax,ax int 16h clc cmp al,13 jz doit cmp al,27 jnz anykey stc doit: ret anykey endp drawscreen proc mov ah,02h ;use bios video to mov bh,00h ;set cursor position to top left mov dx,00h ;of screen int 10h ;bios function 02h ; mov ah,09h ;now using function 09h mov cx,04000 ;print a space char 04000h times mov al,177 ;char to clear with mov bl,13h ;attribute of character int 10h ;clear it! ; mov ah,02h ;now let's put the mov bh,00h ;cursor back up in mov dx,00h ;the upper left corner int 10h ;bios video function ;draw the box + shadow mov dh,25 ;draw box mov dl,15 ;move cursor to row,17 mov al,219 mov cx,50 mov bl,1 mov si,14 ;depth of box call draw_line mov dh,25 mov dl,65 ;draw vertical shadow mov al,176 mov cx,1 mov si,13 mov bl,8 call draw_line mov dh,26 mov dl,16 mov al,176 ;draw under shadow mov cx,50 mov si,1 mov bl,8 call draw_line ;display text in window ret drawscreen endp check4driveready proc ; read disk up to 3 times waiting for drive to read/write OK. push ax push bx push cx push dx push bp push si push di mov bp,3 readflop: dec bp jz floppyerror mov ax,0 mov dl,0 int 13h mov ax, 0201h ; do a fake read of drive A: lea bx, endflag mov cx, 1 mov dx, 0 int 13h jc readflop mov ax, 0301h int 13h ; write data back, check for WP jc readflop jmp driveisready floppyerror: ; save the screen so we can "pop up" error window lea di, endflag ;es is already pointing there xor si, si push ds mov ax, 0b800h mov ds, ax mov cx, 80*2*50 rep movsb pop ds mov dh, 25 ; draw box mov dl, 15 ; move cursor to row,17 mov al, 219 mov cx, 50 mov bl, 4 ; red mov si, 14 ; depth of box call draw_line lea bp,floperror stc ; carry=red text call dotext call anykey jc bail lea si, endflag ; restore screen xor di, di push es mov ax, 0b800h mov es, ax mov cx, 80*2*50 rep movsb pop es driveisready: pop di pop si pop bp pop dx pop cx pop bx pop ax ret bail: mov ax, 3 int 10h mov ax, 4c01h int 21h check4driveready endp findlastsector proc ;exits with CX, DX pointing to last sector on current disk ; read existing boot sector lea bx,endflag mov ax,0201h mov cx,1 mov dx,0 int 13h ; save boot sector to last sector on diskette. ; 1st, see if this is 40 or 80 tracks. lea bx, endflag mov si, bx ; add bx, 512 ; make room for new sector to read add si, 18h mov cl, byte ptr[si] ; load maximum sectors/track add si, 2 mov dh, byte ptr[si] ; load maximum heads/disk dec dh ; make 0 based mov ch, 79 ; try HDD disk 1st mov ax, 0201h readlastsector: push ax push bx push cx push dx push si int 13h ; save all registers, cuz we'll need pop si ; em again in a second pop dx pop cx pop bx pop ax jnc findlastexit ; must be a low density disk mov ch, 39h jmp readlastsector findlastexit: ret findlastsector endp write_bootsector proc ;this routine writes the actual boot sector to the floppy drive and makes ;sure the drive is ready and readable. call check4driveready mov ax, 0201h lea bx, endflag mov cx, 1 mov dx, 0 int 13h call findlastsector push cx push dx mov ax, 0301h lea bx, endflag ; point back to original bootsector int 13h ; save to last sector on disk ; no error check; we'll get that pop dx ; on the next write. pop cx lea si, oldsectorcx ; save off cx/dx of orig boot sector mov word ptr [si], cx ; for loading at next boot. lea si, oldsectordx mov word ptr [si], dx mov ax, 0 ; reset mov dl, 0 int 13h mov ax, 0301h ; write new boot sector lea bx, bootsector mov dx, 0 mov cx, 1 int 13h ret jmp write_bootsector write_bootsector endp write_vectable proc ;this routine reads the vector table from the floppy disk and write it to a ;file. call check4driveready mov ax, 0201h lea bx, endflag mov cx, 1 mov dx, 0 int 13h call findlastsector dec cl ; back up by 1 sector mov ax,0 mov dl,0 int 13h lea bx,endflag mov ax,0202h int 13h mov ah,3ch ;open our filename mov cx,0 ; lea dx,vectortbl ;no error checking. int 21h ;this shouldn't fail mov bx,ax mov ah,40h ;write contents to a file mov cx,1024 ;write 1k of data lea dx,endflag ; int 21h ;no error checking ; jc writeerror ;if this fails, there are ;bigger problems to deal with. mov ah,3eh ;close file int 21h ret write_vectable endp go: mov ax,3 int 10h mov ax,1112h int 10h ;switch to 80x50 ; see where we are in the installation process. push bx push es mov bx,40h mov es,bx mov bx,0f0h cmp byte ptr es:[bx],MAGIC mov byte ptr es:[bx],0 pop es pop bx jnz begining call drawscreen lea bp, endingmsg call dotext call anykey jc exit call write_vectable call drawscreen lea bp, finished call dotext xor ax,ax ;wait for a key int 16h jmp bail ;done begining: call drawscreen lea bp,welcomemsg call dotext call anykey jc exit call drawscreen lea bp,step1 call dotext call anykey jc exit call drawscreen lea bp,step2 call dotext call anykey jc exit call drawscreen lea bp,step3 call dotext call anykey jc exit call write_bootsector call drawscreen lea bp,step4 call dotext call anykey jc exit ;create flag file for when we come back. mov ax,-1 push ax ; jump to FFFF:0 for a reboot! mov ax,0 push ax retf exit: mov ax,3 int 10h mov ax,4c01h int 21h endflag: cseg ends end main