amd64/bareMetalOS-0.5.3/programs/nibbles.asm

   1 ; The classic game of Nibbles
   2 ; Written by Ian Seyler
   3 ;
   4 ; BareMetal compile:
   5 ; nasm argtest.asm -o argtest.app
   6
   7 ; Game field is surrounded by a border. Play area is 38 x 23
   8
   9 [BITS 64]
  10 [ORG 0x0000000000200000]
  11
  12 %INCLUDE "bmdev.asm"
  13
  14 start:                                  ; Start of program label
  15         call b_hide_statusbar
  16         call b_hide_cursor
  17         call b_screen_clear
  18
  19         mov rdi, os_screen              ; Screen framebuffer
  20
  21         mov eax, 0x15DB15DB
  22         mov rcx, 41
  23         rep stosd                       ; Draw the top wall
  24
  25         mov rcx, 23
  26 nextside:                               ; Draw the side walls
  27         add rdi, 152
  28         stosd
  29         stosd
  30         sub rcx, 1
  31         cmp rcx, 0
  32         jne nextside
  33
  34         mov rcx, 39
  35         rep stosd                       ; Draw the bottom wall
  36
  37         call b_screen_update            ; Copy the screen buffer to video memory
  38
  39
  40
  41 gameloop:
  42         cmp byte [direction], 1
  43         je move_up
  44         cmp byte [direction], 2
  45         je move_right
  46         cmp byte [direction], 3
  47         je move_down
  48         cmp byte [direction], 4
  49         je move_left
  50         jmp fin                         ; Fatal error
  51
  52 move_up:
  53         sub byte [head_x], 1
  54         jmp drawworm
  55 move_right:
  56         add byte [head_y], 1
  57         jmp drawworm
  58 move_down:
  59         add byte [head_x], 1
  60         jmp drawworm
  61 move_left:
  62         sub byte [head_y], 1
  63         jmp drawworm
  64
  65 drawworm:
  66         mov rax, 1
  67         call b_delay
  68         mov ah, byte [head_y]
  69         shl ah, 1
  70         mov al, byte [head_x]
  71         call b_move_cursor
  72         mov al, 219
  73         call b_print_char
  74         call b_print_char
  75         call b_input_key_check
  76         cmp al, 'w'
  77         je go_up
  78         cmp al, 'a'
  79         je go_left
  80         cmp al, 's'
  81         je go_down
  82         cmp al, 'd'
  83         je go_right
  84         cmp al, 'q'
  85         je fin
  86         jmp gameloop
  87
  88 go_up:
  89         mov byte [direction], 1
  90         jmp gameloop
  91
  92 go_left:
  93         mov byte [direction], 4
  94         jmp gameloop
  95
  96 go_down:
  97         mov byte [direction], 3
  98         jmp gameloop
  99
 100 go_right:
 101         mov byte [direction], 2
 102         jmp gameloop
 103
 104 fin:
 105         call b_screen_clear
 106         mov ax, 0x0018                  ; Set the hardware cursor to the bottom left-hand corner
 107         call b_move_cursor
 108         call b_show_cursor
 109         call b_show_statusbar
 110         ret                             ; Return to OS
 111
 112 head_x:         db 5
 113 head_y:         db 5
 114 direction:      db 2                    ; 1 up, 2 right, 3 down, 4 left
 115
 116 os_screen:      equ 0x0000000000180000  ; This is the address for the text screen frame buffer. It gets copied to video memory via b_update_screen