format MZ ;Specify the .EXE format entry MainSeg:start org 0100h stack $3000 ;org 100h ;specify origin ;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;Constants ;;;;;;;;;;;;;;;;;;;;;;;;;;;; COLUMNS = 8 LINES = 8 FIELDX = 16 FIELDY = 4 ;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;Code ;;;;;;;;;;;;;;;;;;;;;;;;;;;; segment MainSeg use16 start: mov al,13h ;AX=0000 at program start int 10h ;init mode 13h push word 0A000h ;Requires 80186 or higher to PUSH IMMED pop es ;ES now points to mode 13h screen segment mov ax, DataSeg mov ds, ax ;DS now points to our data segment call createminefield ;Initialize the map with mines call calculateminenumbers ;Populate the numbers call drawfield ;Draw the map jmp mainloop ;Main event and game loop ; Draw the field drawfield: mov cx, 00h mov ax, 00h drawfieldloop: push cx push ax call getbmp add cx, FIELDY ; Make sure we get the field displaced correctly add ax, FIELDX call drawbox pop ax pop cx inc cx cmp cx, COLUMNS jne drawfieldloop mov cx, 0h inc ax cmp ax, LINES jne drawfieldloop mov ax, [cursorx] add ax, FIELDX mov cx, [cursory] add cx, FIELDY ; Make sure we get the cursor displaced correctly mov bx, cursorbmp call drawbox ret getbmp: push cx ; Store the values before scr$%&ing them push ax call peektable pop ax ; Recover the values of AX and BX pop cx cmp dh, 01h ; Covered cell je iscovered cmp dh, 02h ; Flagged cell je isflagged cmp dx, 00009h ; There's a mine je mine cmp dx, 00008h je puteight cmp dx, 00007h je putseven cmp dx, 00006h je putsix cmp dx, 00005h je putfive cmp dx, 00004h je putfour cmp dx, 00003h je putthree cmp dx, 00002h je puttwo cmp dx, 00001h je putone mov bx, emptycell ; Point to the emptycell bitmap ret iscovered: mov bx, covercell ; Point to the covered cell ret isflagged: mov bx, flagbmp ; Point to the flag bitmap ret mine: mov bx, minebmp ; Point to the mine cell ret putone: mov bx, numone ; Point to the corresponding number cell ret puttwo: mov bx, numtwo ; Point to the corresponding number cell ret putthree: mov bx, numthree ; Point to the corresponding number cell ret putfour: mov bx, numfour ; Point to the corresponding number cell ret putfive: mov bx, numfive ; Point to the corresponding number cell ret putsix: mov bx, numsix ; Point to the corresponding number cell ret putseven: mov bx, numseven ; Point to the corresponding number cell ret puteight: mov bx, numeight ; Point to the corresponding number cell ret ;Random subroutines here initseed: mov ah, 02Ch ;Select Get System Time function int 021h ;Call DOS add cx, dx ;Add the seconds and milliseconds to add more randomness mov word [seed], cx ;In CX we have our new seed ret random: mov ax, 25173 ;LCG multiplier mul word [seed] ;DX:AX = LCG multiplier * seed add ax, 13849 ;Add LCG increment value mov word [seed], ax ;Update seed, AX has the random number now ret ;This is thought to pick up from the registers the address of what we need to draw ;Draw it, and return. The params are: ;- AX -> X position ;- CX -> Y position ;- BX -> base memory address of the bitmap drawbox: push ax ;Save the X value for later mov ax, cx ;Prepare for multiplications mov dx, 0A00h mul dx mov cx, ax ;Retrieve the line into CX pop ax ;Retrieve the X value into AX register mov dx, COLUMNS mul dx ;We multiply the X value too for the 8x8 add cx, ax ;Now we've put in AX the pointer value mov si, cx ;Set SI to the correct address we'll draw mov cx, 00 mov ax, 00 mov dx, 00 drawloop: mov al, byte [ds:bx] ;Current address in BX cmp al, 0ffh ;This is transparent pixel, don't draw je dontdraw mov byte [es:si], al ;Put the pixel into RAM dontdraw: inc bx inc cx inc dx cmp dx, 08h ;Sort of modulo je jumplinedraw ;Time to increment SI in a more complex way inc si continuecomp: cmp cx, 040h ;Compare CX to hex 64 (8x8) jne drawloop ;Continue ret ;Return jumplinedraw: mov dx, 00h add si, 313 ;Jump a whole line jmp continuecomp ;Continue the routine ;This function populates the minefield with mines createminefield: call initseed ;Make sure we have a good seed mov dx, 00h ;DX will be our pointer mov bx, map ;BX our base pointer cmfloop: push dx ;Save our counters before generating random number push bx call random ;This leaves a random num in AX pop bx ;Recover our counters pop dx cmp al, 0FFh ;Compare if it's greater than 240 je putmine ;Put a mine here continuecreateminefield: add bx, 02h inc dx cmp dx, COLUMNS * LINES ; Check we have done the whole map jl cmfloop cmp byte [minecount], 10 ; Check we've put all mines! jl createminefield finishcreateminefield: ret ; All is ok putmine: cmp byte [minecount], 10 jge finishcreateminefield cmp word [ds:bx], 00109h ;Check memory for placed mine je continuecreateminefield inc byte [minecount] mov word [ds:bx], 00109h ;Place mine jmp continuecreateminefield ;This routine returns in DX the value of the cell pointed by CX (Y coord) and ;AX (X coord) ;Mangles AX, BX, CX and DX peektable: mov dx, 0 ;In case we return prematurely, we return nothing cmp ax, COLUMNS ;If we are out of bounds, return jge peekend cmp cx, LINES jge peekend push ax ;Calculate offset mov ax, cx mov cx, COLUMNS mul cx mov cx, ax pop ax add ax, cx mov cx, 2 mul cx mov bx, map add bx, ax mov dx, word [ds:bx] ;Read peekend: ret calcnumber: push ax push cx call peektable pop cx cmp dx, 00109h jne calcend mov al, byte [tempnumber] inc al mov byte [tempnumber], al calcend: pop ax ret checksurroundings: mov byte [tempnumber], 0 push ax push cx sub ax, 1 sub cx, 1 call calcnumber add ax, 1 call calcnumber add ax, 1 call calcnumber pop cx pop ax push ax push cx sub ax, 1 call calcnumber add ax, 2 call calcnumber pop cx pop ax push ax push cx add cx, 1 sub ax, 1 call calcnumber add ax, 1 call calcnumber add ax, 1 call calcnumber pop cx mov bx, map mov ax, cx mov dx, COLUMNS mul dx mov dx, ax pop ax push ax add dx, ax mov ax, dx mov dx, 2 mul dx add bx, ax pop ax mov dx, 00100h mov dl, byte [tempnumber] mov word [ds:bx], dx ret ;This routine checks the map and puts numbers down given the ;amount of mines around calculateminenumbers: mov ax, 0 mov cx, 0 cmnloop: push ax push cx call peektable pop cx pop ax cmp dx, 00109h je cmncontinue call checksurroundings cmncontinue: inc ax cmp ax, COLUMNS jl cmnloop mov ax, 0 inc cx cmp cx, LINES jl cmnloop ret mainloop: ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;This is where you do your mega-amazing tiny program. ;Write 8-bit values to A000:0000 to draw some pixels. ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;Check for user input or wanting to leave by pressing ESC in al,60h ;read whatever is at keyboard port; looking for ESC which is #1 cmp al,48h je upkey cmp al,4bh je leftkey cmp al,4dh je rightkey cmp al,50h je downkey cmp al,39h je space cmp al,38h je lalt mov word [lastkeypressed], 0h ;Reset the current key as it is not one we are checking dec al ;if ESC, AL now 0 jnz mainloop ;fall through if 0, jump otherwise exit: mov al,03 ;AX=0000 due to mainloop exit condition int 10h ;Switch back to text mode as a convenience mov ah,4Ch ;Function to exit, now we are an EXE, do it correctly mov al,00 ;Exit code as 0, everything went well int 21h gameover: mov ah, 0 mov al,03 ;AX=0000 due to mainloop exit condition int 10h ;Switch back to text mode as a convenience mov dx, gameoverstr mov ah, 09h int 21h mov ah,4Ch ;Function to exit, now we are an EXE, do it correctly mov al,00 ;Exit code as 0, everything went well int 21h redraw: call drawfield jmp mainloop leftkey: cmp ax, [lastkeypressed] je mainloop mov [lastkeypressed], ax mov ax, [cursorx] dec ax updatelateralmovement: cmp ax, COLUMNS - 1 jg redraw cmp ax, 0 jl redraw mov [cursorx], ax jmp redraw rightkey: cmp ax, [lastkeypressed] je mainloop mov [lastkeypressed], ax mov ax, [cursorx] inc ax jmp updatelateralmovement upkey: cmp ax, [lastkeypressed] je mainloop mov [lastkeypressed], ax mov cx, [cursory] dec cx updateverticalmovement: cmp cx, LINES - 1 jg redraw cmp cx, 0 jl redraw mov [cursory], cx jmp redraw downkey: cmp ax, [lastkeypressed] je mainloop mov [lastkeypressed], ax mov cx, [cursory] inc cx jmp updateverticalmovement space: cmp ax, [lastkeypressed] je mainloop mov [lastkeypressed], ax mov ax, [cursorx] mov cx, [cursory] call uncover mov ax, [cursorx] mov cx, [cursory] call peektable cmp dx, 00009h je gameover jmp redraw lalt: cmp ax, [lastkeypressed] je mainloop mov [lastkeypressed], ax mov ax, [cursorx] mov cx, [cursory] call setflag jmp redraw getoffset: cmp ax, COLUMNS ;If we are out of bounds, return jl checky ret checky: cmp cx, LINES jl inbounds ret inbounds: push ax ;Calculate offset mov ax, cx mov cx, COLUMNS mul cx mov cx, ax pop ax add ax, cx mov cx, 2 mul cx mov bx, map add bx, ax ret uncover: call getoffset mov dx, word [ds:bx] ;Read mov dh, 00h ;Set upperbit as 0 mov word [ds:bx], dx ret setflag: call getoffset mov dx, word [ds:bx] ;Read mov dh, 02h ;Set upperbit as 0 mov word [ds:bx], dx ret ;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;Data segment ;;;;;;;;;;;;;;;;;;;;;;;;;;;;; segment DataSeg use16 lastkeypressed: dw 0 seed: dw 0 minecount: db 0 tempnumber: db 0 cursorx: dw 0 cursory: dw 0 gameoverstr: db "Game over!$" youwinstr: db "You win!$" ;Game map. First 8 bytes are for the cell status ;the last 8 bytes are for the cell contents. ; ;Cell status: 0 covered, 1 uncovered, 2 flagged ;Cell content: 0 empty, 1-8 number, 9 mine map: dw COLUMNS * LINES dup 00h covercell: db 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh db 0fh, 17h, 17h, 17h, 17h, 17h, 17h, 14h db 0fh, 17h, 17h, 17h, 17h, 17h, 17h, 14h db 0fh, 17h, 17h, 17h, 17h, 17h, 17h, 14h db 0fh, 17h, 17h, 17h, 17h, 17h, 17h, 14h db 0fh, 17h, 17h, 17h, 17h, 17h, 17h, 14h db 0fh, 17h, 17h, 17h, 17h, 17h, 17h, 14h db 14h, 14h, 14h, 14h, 14h, 14h, 14h, 14h emptycell: db 14h, 14h, 14h, 14h, 14h, 14h, 14h, 14h db 14h, 17h, 17h, 17h, 17h, 17h, 17h, 0fh db 14h, 17h, 17h, 17h, 17h, 17h, 17h, 0fh db 14h, 17h, 17h, 17h, 17h, 17h, 17h, 0fh db 14h, 17h, 17h, 17h, 17h, 17h, 17h, 0fh db 14h, 17h, 17h, 17h, 17h, 17h, 17h, 0fh db 14h, 17h, 17h, 17h, 17h, 17h, 17h, 0fh db 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh minebmp: db 14h, 14h, 14h, 14h, 14h, 14h, 14h, 14h db 14h, 10h, 17h, 10h, 17h, 17h, 10h, 0fh db 14h, 17h, 10h, 10h, 10h, 10h, 17h, 0fh db 14h, 17h, 10h, 10h, 0fh, 10h, 10h, 0fh db 14h, 10h, 10h, 10h, 10h, 10h, 17h, 0fh db 14h, 17h, 10h, 10h, 10h, 10h, 17h, 0fh db 14h, 10h, 17h, 17h, 10h, 17h, 10h, 0fh db 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh flagbmp: db 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh db 0fh, 17h, 17h, 04h, 10h, 17h, 17h, 14h db 0fh, 17h, 04h, 04h, 10h, 17h, 17h, 14h db 0fh, 04h, 04h, 04h, 10h, 17h, 17h, 14h db 0fh, 17h, 17h, 17h, 10h, 17h, 17h, 14h db 0fh, 17h, 17h, 17h, 10h, 17h, 17h, 14h db 0fh, 17h, 10h, 10h, 10h, 10h, 10h, 14h db 14h, 14h, 14h, 14h, 14h, 14h, 14h, 14h numone: db 14h, 14h, 14h, 14h, 14h, 14h, 14h, 14h db 14h, 17h, 17h, 17h, 01h, 17h, 17h, 0fh db 14h, 17h, 17h, 01h, 01h, 17h, 17h, 0fh db 14h, 17h, 01h, 17h, 01h, 17h, 17h, 0fh db 14h, 17h, 17h, 17h, 01h, 17h, 17h, 0fh db 14h, 17h, 17h, 17h, 01h, 17h, 17h, 0fh db 14h, 17h, 01h, 01h, 01h, 01h, 01h, 0fh db 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh numtwo: db 14h, 14h, 14h, 14h, 14h, 14h, 14h, 14h db 14h, 17h, 17h, 02h, 02h, 02h, 17h, 0fh db 14h, 17h, 02h, 17h, 17h, 17h, 02h, 0fh db 14h, 17h, 17h, 17h, 17h, 17h, 02h, 0fh db 14h, 17h, 17h, 02h, 02h, 02h, 17h, 0fh db 14h, 17h, 02h, 17h, 17h, 17h, 17h, 0fh db 14h, 17h, 02h, 02h, 02h, 02h, 02h, 0fh db 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh numthree: db 14h, 14h, 14h, 14h, 14h, 14h, 14h, 14h db 14h, 17h, 17h, 04h, 04h, 04h, 17h, 0fh db 14h, 17h, 04h, 17h, 17h, 17h, 04h, 0fh db 14h, 17h, 17h, 17h, 17h, 17h, 04h, 0fh db 14h, 17h, 17h, 17h, 04h, 04h, 17h, 0fh db 14h, 17h, 04h, 17h, 17h, 17h, 04h, 0fh db 14h, 17h, 17h, 04h, 04h, 04h, 17h, 0fh db 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh numfour: db 14h, 14h, 14h, 14h, 14h, 14h, 14h, 14h db 14h, 17h, 17h, 17h, 05h, 05h, 17h, 0fh db 14h, 17h, 17h, 05h, 17h, 05h, 17h, 0fh db 14h, 17h, 05h, 17h, 17h, 05h, 17h, 0fh db 14h, 17h, 05h, 05h, 05h, 05h, 05h, 0fh db 14h, 17h, 17h, 17h, 17h, 05h, 17h, 0fh db 14h, 17h, 17h, 17h, 05h, 05h, 05h, 0fh db 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh numfive: db 14h, 14h, 14h, 14h, 14h, 14h, 14h, 14h db 14h, 17h, 06h, 06h, 06h, 06h, 06h, 0fh db 14h, 17h, 06h, 17h, 17h, 17h, 17h, 0fh db 14h, 17h, 06h, 17h, 17h, 17h, 17h, 0fh db 14h, 17h, 17h, 06h, 06h, 06h, 17h, 0fh db 14h, 17h, 17h, 17h, 17h, 17h, 06h, 0fh db 14h, 17h, 06h, 06h, 06h, 06h, 17h, 0fh db 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh numsix: db 14h, 14h, 14h, 14h, 14h, 14h, 14h, 14h db 14h, 17h, 17h, 17h, 2bh, 2bh, 17h, 0fh db 14h, 17h, 17h, 2bh, 17h, 17h, 17h, 0fh db 14h, 17h, 2bh, 17h, 17h, 17h, 17h, 0fh db 14h, 17h, 2bh, 2bh, 2bh, 2bh, 17h, 0fh db 14h, 17h, 2bh, 17h, 17h, 17h, 2bh, 0fh db 14h, 17h, 17h, 2bh, 2bh, 2bh, 17h, 0fh db 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh numseven: db 14h, 14h, 14h, 14h, 14h, 14h, 14h, 14h db 14h, 17h, 35h, 35h, 35h, 35h, 35h, 0fh db 14h, 17h, 17h, 17h, 17h, 17h, 35h, 0fh db 14h, 17h, 17h, 17h, 17h, 35h, 17h, 0fh db 14h, 17h, 17h, 17h, 35h, 17h, 17h, 0fh db 14h, 17h, 17h, 17h, 35h, 17h, 17h, 0fh db 14h, 17h, 17h, 17h, 35h, 17h, 17h, 0fh db 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh numeight: db 14h, 14h, 14h, 14h, 14h, 14h, 14h, 14h db 14h, 17h, 17h, 40h, 40h, 40h, 17h, 0fh db 14h, 17h, 40h, 17h, 17h, 17h, 40h, 0fh db 14h, 17h, 17h, 40h, 40h, 40h, 17h, 0fh db 14h, 17h, 40h, 17h, 17h, 17h, 40h, 0fh db 14h, 17h, 40h, 17h, 17h, 17h, 40h, 0fh db 14h, 17h, 17h, 40h, 40h, 40h, 17h, 0fh db 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh cursorbmp: db 2ah, 2ah, 2ah, 2ah, 2ah, 2ah, 2ah, 2ah db 2ah, 0ffh, 0ffh, 0ffh, 0ffh, 0ffh, 0ffh, 2ah db 2ah, 0ffh, 0ffh, 0ffh, 0ffh, 0ffh, 0ffh, 2ah db 2ah, 0ffh, 0ffh, 0ffh, 0ffh, 0ffh, 0ffh, 2ah db 2ah, 0ffh, 0ffh, 0ffh, 0ffh, 0ffh, 0ffh, 2ah db 2ah, 0ffh, 0ffh, 0ffh, 0ffh, 0ffh, 0ffh, 2ah db 2ah, 0ffh, 0ffh, 0ffh, 0ffh, 0ffh, 0ffh, 2ah db 2ah, 2ah, 2ah, 2ah, 2ah, 2ah, 2ah, 2ah