└── bootris.s


/bootris.s:
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  1 | %define HEIGHT 22
  2 | KEYBOARD_INTERRUPT EQU 9
  3 | TIMER_INTERRUPT EQU 8
  4 | 
  5 | TIMER_MOD EQU 0
  6 | 
  7 | STACK_SEGMENT EQU 09000h	; Top of conventional memory
  8 | STACK_SIZE EQU 0ffffh		; 64K - 1 bytes of stack
  9 | 
 10 | ORG 0x7C00
 11 | 
 12 | block_L: db 0x17,0
 13 | 		 db 0x22,0x30
 14 | 		 db 0x71,0
 15 | 		 db 0x30,0x22
 16 | 
 17 | ; initialize the stack
 18 | cli
 19 | push word 0
 20 | pop ds
 21 | mov [4 * KEYBOARD_INTERRUPT], word keyboard_interrupt
 22 | mov [4 * KEYBOARD_INTERRUPT + 2], cs
 23 | mov [4 * TIMER_INTERRUPT], word timer_interrupt
 24 | mov [4 * TIMER_INTERRUPT + 2], cs
 25 | mov sp, STACK_SEGMENT
 26 | mov ss, sp
 27 | mov sp, STACK_SIZE
 28 | push cs
 29 | pop ds
 30 | ; and jump to the main code
 31 | jmp 0x0000:start
 32 | 
 33 | title: dw 'TETRIS'
 34 | world1: times 32 db 205
 35 | 
 36 | start:
 37 | 	mov word [counter], 0
 38 | 	mov byte [timer_mod], 100
 39 | 	call BiosClearScreen
 40 | 	mov ax, title
 41 | 	mov dh,0
 42 | 	mov dl,37
 43 | 	mov cx,6
 44 | 	call puts
 45 | 	call draw_boarder
 46 | 	mov word [next_obj],block_L
 47 | 	
 48 | 	;start game
 49 | 	sti
 50 | 	hlt
 51 | 
 52 | do_new_object:
 53 | 	mov word ax, [next_obj]
 54 | 	mov word [current_obj], ax
 55 | 	mov byte [obj_height],0
 56 | 	mov byte [offset],0
 57 | 	mov byte [rotation],0
 58 | 	ret
 59 | 
 60 | draw_boarder:
 61 | 	mov dh, 1
 62 | 	mov dl,24
 63 | 	mov cx, 32
 64 | 	mov ax, world1
 65 | 	call puts
 66 | 	add dh, HEIGHT
 67 | 	call puts
 68 | 	
 69 | 	dec dh
 70 | 	.loop: 
 71 | 		mov dl, 23
 72 | 		mov ax, 0x0200
 73 | 		xor bx, bx
 74 | 		int 0x10
 75 | 		mov cx, 1
 76 | 		mov ah, 0x0A
 77 | 		mov al, 186
 78 | 		int 0x10
 79 | 		mov dl, 56
 80 | 		mov ax, 0x0200
 81 | 		xor bx, bx
 82 | 		int 0x10
 83 | 		mov cx, 1
 84 | 		mov ah, 0x0A
 85 | 		mov al, 186
 86 | 		int 0x10
 87 | 		dec dh
 88 | 		
 89 | 		cmp dh, 1
 90 | 		jnz .loop
 91 | 	ret
 92 | 
 93 | puts:
 94 | 	pusha
 95 | 	mov bp, ax
 96 | 	mov ax, 0x1300
 97 | 	mov bx, 7
 98 | 	int 0x10
 99 | 	popa
100 | 	ret
101 | 	
102 | do_game_tick:
103 | 	call draw_boarder
104 | 	ret
105 | 
106 | keyboard_interrupt:
107 | 	; save our registers!
108 | 	pusha
109 | 	in al, 60h
110 | 	; Ignore codes with high bit set
111 | 	test al, 80h
112 | 	jnz EOI
113 | 	; Read the ASCII code from the table
114 | 	mov cx, 1
115 | 	mov ah, 0x0A
116 | 	int 0x10
117 | 	jmp EOI
118 | 
119 | timer_interrupt:
120 | 	pusha
121 | 	mov ax, [counter]
122 | 	or ax, ax
123 | 	jnz .end
124 | 	; we hit zero! Do the game tick...
125 | 	call do_game_tick
126 | 	mov word [counter], 10
127 | 	mov cx, 1
128 | 	mov ah, 0x0A
129 | 	int 0x10
130 | 	.end:
131 | 	dec word [counter]
132 | 	; fall through
133 | EOI:
134 | 	mov al, 20h
135 | 	out 20h, al
136 | 	popa
137 | 	iret
138 | 
139 | BiosClearScreen:
140 | 	pusha
141 | 	mov ax,0x0600   ; clear the "window"
142 | 	xor cx, cx
143 | 	mov dx,0x184f   ; to (24,79)
144 | 	mov bh,0x07     ; keep light grey display
145 | 	int 0x10
146 | 	popa
147 | 	ret
148 | 
149 | ; last two bytes must be 55 AA
150 | times 510-($-$$) db 0
151 | db 0x55
152 | db 0xAA
153 | 
154 | absolute 0x7e00
155 | counter: resw 1
156 | timer_mod: resb 1
157 | arena: times HEIGHT resw 1
158 | current_obj: resw 1
159 | next_obj: resw 1
160 | obj_height: resb 1
161 | offset: resb 1
162 | rotation: resb 1
163 | 


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