Эмулятор процессора Intel 8086 версия 4.05 (ENG) / asm_files / snake.asm

Assembler Source Code a:link {text-decoration: none} a:visited {text-decoration: none} a:hover {text-decoration: none; color:#ff0000}     ; snake.asm ; this is the screen eating snake game... ; ; this game pushes the emulator to its limits, ; and even with maximum speed it still runs slowly. ; to enjoy this game it's recommended to run it on real ; computer, however the emulator can be useful to debug ; tiny games and other similar programs such as this before ; they become bug-free and workable. ; ; you can control the snake using arrow keys on your keyboard. ; ; all other keys will stop the snake. ; ; press esc to exit. name "snake" org 100h ; jump over data section: jmp start ; ------ data section ------ s_size equ 7 ; the snake coordinates ; (from head to tail) ; low byte is left, high byte ; is top - [top, left] snake dw s_size dup(0) tail dw ? ; direction constants ; (bios key codes): left equ 4bh right equ 4dh up equ 48h down equ 50h ; current snake direction: cur_dir db right wait_time dw 0 ; welcome message msg db "==== how to play ====", 0dh,0ah db "this game was debugged on emu8086", 0dh,0ah db "but it is not designed to run on the emulator", 0dh,0ah db "because it requires relatively fast video card and cpu.", 0dh,0ah, 0ah db "if you want to see how this game really works,", 0dh,0ah db "run it on a real computer (click external->run from the menu).", 0dh,0ah, 0ah db "you can control the snake using arrow keys", 0dh,0ah db "all other keys will stop the snake.", 0dh,0ah, 0ah db "press esc to exit.", 0dh,0ah db "====================", 0dh,0ah, 0ah db "press any key to start...$" ; ------ code section ------ start: ; print welcome message: mov dx, offset msg mov ah, 9 int 21h ; wait for any key: mov ah, 00h int 16h ; hide text cursor: mov ah, 1 mov ch, 2bh mov cl, 0bh int 10h game_loop: ; === select first video page mov al, 0 ; page number. mov ah, 05h int 10h ; === show new head: mov dx, snake[0] ; set cursor at dl,dh mov ah, 02h int 10h ; print '*' at the location: mov al, '*' mov ah, 09h mov bl, 0eh ; attribute. mov cx, 1 ; single char. int 10h ; === keep the tail: mov ax, snake[s_size * 2 - 2] mov tail, ax call move_snake ; === hide old tail: mov dx, tail ; set cursor at dl,dh mov ah, 02h int 10h ; print ' ' at the location: mov al, ' ' mov ah, 09h mov bl, 0eh ; attribute. mov cx, 1 ; single char. int 10h check_for_key: ; === check for player commands: mov ah, 01h int 16h jz no_key mov ah, 00h int 16h cmp al, 1bh ; esc - key? je stop_game ; mov cur_dir, ah no_key: ; === wait a few moments here: ; get number of clock ticks ; (about 18 per second) ; since midnight into cx:dx mov ah, 00h int 1ah cmp dx, wait_time jb check_for_key add dx, 4 mov wait_time, dx ; === eternal game loop: jmp game_loop stop_game: ; show cursor back: mov ah, 1 mov ch, 0bh mov cl, 0bh int 10h ret ; ------ functions section ------ ; this procedure creates the ; animation by moving all snake ; body parts one step to tail, ; the old tail goes away: ; [last part (tail)]-> goes away ; [part i] -> [part i+1] ; .... move_snake proc near ; set es to bios info segment: mov ax, 40h mov es, ax ; point di to tail mov di, s_size * 2 - 2 ; move all body parts ; (last one simply goes away) mov cx, s_size-1 move_array: mov ax, snake[di-2] mov snake[di], ax sub di, 2 loop move_array cmp cur_dir, left je move_left cmp cur_dir, right je move_right cmp cur_dir, up je move_up cmp cur_dir, down je move_down jmp stop_move ; no direction. move_left: mov al, b.snake[0] dec al mov b.snake[0], al cmp al, -1 jne stop_move mov al, es:[4ah] ; col number. dec al mov b.snake[0], al ; return to right. jmp stop_move move_right: mov al, b.snake[0] inc al mov b.snake[0], al cmp al, es:[4ah] ; col number. jb stop_move mov b.snake[0], 0 ; return to left. jmp stop_move move_up: mov al, b.snake[1] dec al mov b.snake[1], al cmp al, -1 jne stop_move mov al, es:[84h] ; row number -1. mov b.snake[1], al ; return to bottom. jmp stop_move move_down: mov al, b.snake[1] inc al mov b.snake[1], al cmp al, es:[84h] ; row number -1. jbe stop_move mov b.snake[1], 0 ; return to top. jmp stop_move stop_move: ret move_snake endp

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