COMMENT % ÉÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ» º Fire! Routine 1.01 ÇÄ¿ ÇÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄĶ ³ º Well, here's the second demo program in the tutorial º ³ º series. Exams delayed this a bit, but all in all it took º ³ º me about a day - (11AM -> 8PM) - to do. Yes, I spent º ³ º quite a while fine tuning this. º ³ º º ³ º You are free to modify and use this code in your programs, º ³ º just don't put your name on it and redistribute it - okay? º ³ º The program can also be improved upon greatly, so if you º ³ º make something good from this - send it to me. I like to º ³ º see what people have done with my work. º ³ º º ³ º 28th June 1996 º ³ º º ³ º Contact Adam Hyde at: º ³ º þ http://www.faroc.com.au/~blackcat º ³ º þ blackcat@faroc.com.au º ³ º º ³ º (C) 1996 Adam Hyde. º ³ ÈÑÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍͼ ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ % .MODEL SMALL ; Data segment < 64K, code segment < 64K .STACK 200H ; Set up 512 bytes of stack space .386 ; =========================================================================== .DATA CR EQU 13 LF EQU 10 BufferX EQU 320 ; Width of screen buffer BufferY EQU 104 ; Height of screen buffer AllDone DB CR, LF, "That was:" DB CR, LF DB CR, LF, " FFFFFFFFF IIIIIII RRRRRRRRR EEEEEEEEE ! " DB CR, LF, " FFF III RRR RRR EEE !!! " DB CR, LF, " FFF III RRR RRR EEE !!!!!" DB CR, LF, " FFF III RRRRRRRR EEE !!!!!" DB CR, LF, " FFFFFFF III RRRRRRRR EEEEEEEE !!!!!" DB CR, LF, " FFF III RRR RRR EEE !!! " DB CR, LF, " FFF III RRR RRR EEE " DB CR, LF, " FFF III RRR RRR EEE !!! " DB CR, LF, " FFFFF IIIIIII RRRR RRRR EEEEEEEEE !!! " DB CR, LF DB CR, LF DB CR, LF, " The demo program from Assembler Tutorial 8. You can get in touch with the" DB CR, LF, " author, Adam Hyde, at:", CR, LF DB CR, LF, " þ blackcat@faroc.com.au" DB CR, LF, " þ http://www.faroc.com.au/~blackcat", CR, LF, "$" Buffer DB BufferX * BufferY DUP (?) ; The screen buffer Seed DW 3749h ; The seed value, and half of my ; phone number - not in hex though. :) INCLUDE PALETTE.DAT ; The palette, generated with ; Autodesk Animator, and a simple ; Pascal program. ; =========================================================================== .CODE InitializeMCGA PROC MOV AX, 0A000h MOV ES, AX ; ES now points to the VGA MOV AH, 00H ; Set video mode MOV AL, 13H ; Mode 13h INT 10H ; We are now in 320x200x256 RET InitializeMCGA ENDP ; --------------------------------------------------------------------------- SetUpPalette PROC MOV SI, OFFSET Palette ; SI now points to the palette MOV CX, 768 ; Prepare for 768 OUTs MOV DX, 03C8H ; Palette WRITE register XOR AL, AL ; Start at color 0 CLI ; Disable interrupts OUT DX, AL ; Send value CLD ; Forward direction INC DX ; Now use palette DATA register REP OUTSB ; 768 multiple OUTs STI ; Enable interrupts RET SetupPalette ENDP ; --------------------------------------------------------------------------- ; This procedure was picked up from comp.lang.asm.x86 - many thanks to the ; unknown author. Random PROC MOV AX, Seed ; Move the seed value into AX MOV DX, 8405H ; Move 8405H into DX MUL DX ; Put 8405H x Seed into DX:AX INC AX ; Increment AX MOV Seed, AX ; We have a new seed RET Random ENDP ; --------------------------------------------------------------------------- DrawScreen PROC MOV SI, OFFSET Buffer ; Point SI to the start of the buffer XOR DI, DI ; Start drawing at 0, 0 MOV BX, BufferY - 4 ; Miss the last four lines from the ; buffer. These lines will not look ; fire-like at all Row: MOV CX, BufferX SHR 1 ; 160 WORDS REP MOVSW ; Move them SUB SI, 320 ; Go back to the start of the array row MOV CX, BufferX SHR 1 ; 160 WORDS REP MOVSW ; Move them DEC BX ; Decrease the number of VGA rows left JNZ Row ; Are we finished? RET DrawScreen ENDP ; --------------------------------------------------------------------------- AveragePixels PROC MOV CX, BufferX * BufferY - BufferX * 2 ; Alter all of the buffer, ; except for the first row and ; last row MOV SI, OFFSET Buffer + 320 ; Start from the second row Alter: XOR AX, AX ; Zero out AX MOV AL, DS:[SI] ; Get the value of the current pixel ADD AL, DS:[SI+1] ; Get the value of pixel to the right ADC AH, 0 ADD AL, DS:[SI-1] ; Get the value of pixel to the left ADC AH, 0 ADD AL, DS:[SI+BufferX] ; Get the value of the pixel underneath ADC AH, 0 SHR AX, 2 ; Divide the total by four JZ NextPixel ; Is the result zero? DEC AX ; No, so decrement it by one NextPixel: MOV DS:[SI-BufferX], AL ; Put the new value into the array INC SI ; Next pixel DEC CX ; One less to do JNZ Alter ; Have we done them all? RET AveragePixels ENDP ; --------------------------------------------------------------------------- TextMode PROC MOV AH, 00H ; Set video mode MOV AL, 03H ; Mode 03h INT 10H ; Enter 80x25x16 mode MOV DX, OFFSET AllDone ; DS:DX points to the ending message MOV AH, 09H INT 21H ; Display the ending message RET TextMode ENDP ; --------------------------------------------------------------------------- Start: MOV AX, @DATA MOV DS, AX ; DS now points to the data segment. CALL InitializeMCGA CALL SetUpPalette MainLoop: CALL AveragePixels MOV SI, OFFSET Buffer + BufferX * BufferY - BufferX SHL 1 ; SI now points to the start of the second last row MOV CX, BufferX SHL 1 ; Prepare to get BufferX x 2 random #s BottomLine: CALL Random ; Get a random number MOV DS:[SI], DL ; Use only the low byte of DX - ie, INC SI ; the number will be 0 --> 255 DEC CX ; One less pixel to do JNZ BottomLine ; Are we done yet? CALL DrawScreen ; Copy the buffer to the VGA MOV AH, 01H ; Check for keypress INT 16H ; Is a key waiting in the buffer? JZ MainLoop ; No, keep on going MOV AH, 00H ; Yes, so get the key INT 16H CALL TextMode MOV AH, 4CH MOV AL, 00H INT 21H ; Return to DOS END Start