298 lines
9.4 KiB
NASM
298 lines
9.4 KiB
NASM
format MZ ;Specify the .EXE format
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entry MainSeg:start
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org 0100h
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stack $3000
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;org 100h ;specify origin
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;Constants
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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COLUMNS = 8
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LINES = 8
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FIELDX = 16
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FIELDY = 4
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;Code
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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segment MainSeg
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use16
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start:
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mov al,13h ;AX=0000 at program start
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int 10h ;init mode 13h
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push word 0A000h ;Requires 80186 or higher to PUSH IMMED
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pop es ;ES now points to mode 13h screen segment
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mov ax, DataSeg
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mov ds, ax ;DS now points to our data segment
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call createminefield ;Initialize the map with mines
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call drawfield ;Draw the map
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jmp mainloop ;Main event and game loop
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; Draw the field
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drawfield:
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mov cx, 00h
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mov ax, 00h
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drawfieldloop:
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push cx
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push ax
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call getbmp
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add cx, FIELDY ; Make sure we get the field displaced correctly
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add ax, FIELDX
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call drawbox
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pop ax
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pop cx
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inc cx
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cmp cx, COLUMNS
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jne drawfieldloop
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mov cx, 0h
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inc ax
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cmp ax, LINES
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jne drawfieldloop
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ret
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getbmp:
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mov bx, map ; Store the base of the map in BX
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push ax ; Don't mangle AX
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mov ax, COLUMNS ; How many columns in AX
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mul cx ; So we now multiply CX (Y coord) by COLUMNS
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add bx, ax ; Add it to the pointer
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pop ax ; Recover AX (X coord)
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add bx, ax ; Add the X coord to BX, now we can read
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cmp word [ds:bx], 0009h ; There's a mine
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jne nomine
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mov bx, minebmp ; Point to the mine bitmap
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ret
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nomine:
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mov bx, covercell ; Point to the covered cell
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ret
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;Random subroutines here
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initseed:
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mov ah, 02Ch ;Select Get System Time function
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int 021h ;Call DOS
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add cx, dx ;Add the seconds and milliseconds to add more randomness
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mov word [seed], cx ;In CX we have our new seed
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ret
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random:
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mov ax, 25173 ;LCG multiplier
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mul word [seed] ;DX:AX = LCG multiplier * seed
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add ax, 13849 ;Add LCG increment value
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mov word [seed], ax ;Update seed, AX has the random number now
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ret
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;This is thought to pick up from the registers the address of what we need to draw
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;Draw it, and return. The params are:
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;- AX -> X position
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;- CX -> Y position
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;- BX -> base memory address of the bitmap
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drawbox:
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push ax ;Save the X value for later
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mov ax, cx ;Prepare for multiplications
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mov dx, 0A00h
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mul dx
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mov cx, ax ;Retrieve the line into CX
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pop ax ;Retrieve the X value into AX register
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mov dx, 08h
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mul dx ;We multiply the X value too for the 8x8
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add cx, ax ;Now we've put in AX the pointer value
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mov si, cx ;Set SI to the correct address we'll draw
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mov cx, 00
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mov ax, 00
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mov dx, 00
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drawloop:
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mov al, byte [ds:bx] ;Current address in BX
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mov byte [es:si], al ;Put the pixel into RAM
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inc bx
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inc cx
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inc dx
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cmp dx, 08h ;Sort of modulo
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je jumplinedraw ;Time to increment SI in a more complex way
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inc si
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continuecomp:
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cmp cx, 040h ;Compare CX to hex 64 (8x8)
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jne drawloop ;Continue
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ret ;Return
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jumplinedraw:
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mov dx, 00h
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add si, 313 ;Jump a whole line
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jmp continuecomp ;Continue the routine
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;This function populates the minefield with mines
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createminefield:
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call initseed ;Make sure we have a good seed
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mov dx, 00h ;DX will be our pointer
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mov bx, map ;BX our base pointer
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cmfloop:
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push dx ;Save our counters before generating random number
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push bx
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call random ;This leaves a random num in AX
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pop bx ;Recover our counters
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pop dx
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cmp al, 0FEh ;Compare if it's greater than 240
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jg putmine ;Put a mine here
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continuecreateminefield:
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add bx, 02h
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inc dx
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cmp dx, COLUMNS * LINES ; Check we have done the whole map
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jl cmfloop
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cmp byte [minecount], 10 ; Check we've put all mines!
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jl createminefield
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finishcreateminefield:
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ret ; All is ok
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putmine:
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cmp byte [minecount], 10
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jge finishcreateminefield
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cmp word [ds:bx], 00009h ;Check memory for placed mine
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je continuecreateminefield
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inc byte [minecount]
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mov word [ds:bx], 00009h ;Place mine
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jmp continuecreateminefield
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;This routine checks the map and puts numbers down given the
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;amount of
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;calculateminenumbers:
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; mov bx, [map]
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; mov dx, 00h
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mainloop:
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;This is where you do your mega-amazing tiny program.
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;Write 8-bit values to A000:0000 to draw some pixels.
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;Check for user input or wanting to leave by pressing ESC
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in al,60h ;read whatever is at keyboard port; looking for ESC which is #1
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; cmp al,48h
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; je upkey
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; cmp al,4bh
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; je leftkey
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; cmp al,4dh
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; je rightkey
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; cmp al,50h
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; je downkey
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; cmp al,39h
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; je space
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; cmp al,38h
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; je lalt
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; mov word [lastkeypressed], 0h ;Reset the current key as it is not one we are checking
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dec al ;if ESC, AL now 0
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jnz mainloop ;fall through if 0, jump otherwise
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exit:
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mov al,03 ;AX=0000 due to mainloop exit condition
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int 10h ;Switch back to text mode as a convenience
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mov ah,4Ch ;Function to exit, now we are an EXE, do it correctly
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mov al,00 ;Exit code as 0, everything went well
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int 21h
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upkey:
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cmp ax, [lastkeypressed]
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je mainloop
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mov [lastkeypressed], ax
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mov ah,02
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mov dl,31h
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int 21h
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jmp mainloop
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leftkey:
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cmp ax, [lastkeypressed]
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je mainloop
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mov [lastkeypressed], ax
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mov ah,02
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mov dl,32h
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int 21h
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jmp mainloop
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rightkey:
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cmp ax, [lastkeypressed]
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je mainloop
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mov [lastkeypressed], ax
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mov ah,02
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mov dl,33h
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int 21h
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jmp mainloop
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downkey:
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cmp ax, [lastkeypressed]
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je mainloop
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mov [lastkeypressed], ax
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mov ah,02
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mov dl,34h
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int 21h
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jmp mainloop
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space:
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cmp ax, [lastkeypressed]
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je mainloop
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mov [lastkeypressed], ax
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mov ah,02
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mov dl,39h
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int 21h
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jmp mainloop
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lalt:
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cmp ax, [lastkeypressed]
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je mainloop
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mov [lastkeypressed], ax
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mov ah,02
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mov dl,38h
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int 21h
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jmp mainloop
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;Data segment
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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segment DataSeg
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use16
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lastkeypressed: db 0
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seed: dw 0
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minecount: db 0
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;Game map. First 8 bytes are for the cell status
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;the last 8 bytes are for the cell contents.
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;
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;Cell status: 0 covered, 1 uncovered, 2 flagged
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;Cell content: 0 empty, 1-8 number, 9 mine
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map: dw COLUMNS * LINES dup 00h
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covercell: db 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh
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db 0fh, 17h, 17h, 17h, 17h, 17h, 17h, 14h
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db 0fh, 17h, 17h, 17h, 17h, 17h, 17h, 14h
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db 0fh, 17h, 17h, 17h, 17h, 17h, 17h, 14h
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db 0fh, 17h, 17h, 17h, 17h, 17h, 17h, 14h
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db 0fh, 17h, 17h, 17h, 17h, 17h, 17h, 14h
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db 0fh, 17h, 17h, 17h, 17h, 17h, 17h, 14h
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db 14h, 14h, 14h, 14h, 14h, 14h, 14h, 14h
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emptycell: db 14h, 14h, 14h, 14h, 14h, 14h, 14h, 14h
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db 14h, 17h, 17h, 17h, 17h, 17h, 17h, 0fh
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db 14h, 17h, 17h, 17h, 17h, 17h, 17h, 0fh
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db 14h, 17h, 17h, 17h, 17h, 17h, 17h, 0fh
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db 14h, 17h, 17h, 17h, 17h, 17h, 17h, 0fh
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db 14h, 17h, 17h, 17h, 17h, 17h, 17h, 0fh
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db 14h, 17h, 17h, 17h, 17h, 17h, 17h, 0fh
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db 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh
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minebmp: db 14h, 14h, 14h, 14h, 14h, 14h, 14h, 14h
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db 14h, 10h, 17h, 10h, 17h, 17h, 10h, 0fh
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db 14h, 17h, 10h, 10h, 10h, 10h, 17h, 0fh
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db 14h, 17h, 10h, 10h, 0fh, 10h, 10h, 0fh
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db 14h, 10h, 10h, 10h, 10h, 10h, 17h, 0fh
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db 14h, 17h, 10h, 10h, 10h, 10h, 17h, 0fh
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db 14h, 10h, 17h, 17h, 10h, 17h, 10h, 0fh
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db 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh
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flagbmp: db 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh, 0fh
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db 0fh, 17h, 17h, 04h, 10h, 17h, 17h, 14h
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db 0fh, 17h, 04h, 04h, 10h, 17h, 17h, 14h
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db 0fh, 04h, 04h, 04h, 10h, 17h, 17h, 14h
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db 0fh, 17h, 17h, 17h, 10h, 17h, 17h, 14h
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db 0fh, 17h, 17h, 17h, 10h, 17h, 17h, 14h
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db 0fh, 17h, 10h, 10h, 10h, 10h, 10h, 14h
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db 14h, 14h, 14h, 14h, 14h, 14h, 14h, 14h
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