ORG 100H ; ADD +100H TO ALL ADDRESSES (REQUIRED FOR .COM FILE).
XOR CX, CX
XOR DX, DX
MOV AX, 0013H
INT 10H ; SET VIDEO MODE WITH AH AND AL
DRAW:
MOV AH, 07H
INT 21H
CMP AL, 73H
JE S
CMP AL, 61H
JE A
CMP AL, 77H
JE W
CMP AL, 64H
JE D
CMP AL, 71H
JE OU
SUB AL, 30H
MOV BL, AL
V:
MOV AL, BL
MOV AH, 0CH
INT 10H
JMP DRAW
OU:
INT 20H
RET
S:
INC DX
CMP DX, 141H
JZ XRD
JMP V
A:
DEC CX
CMP CX, 0FFFFH
JZ XRC
JMP V
W:
DEC DX
CMP DX, 0FFFFH
JZ XRD
JMP V
D:
INC CX
CMP CX, 141H
JZ XRC
JMP V
XRD: XOR DX, DX
JMP DRAW
XRC: XOR CX, CX
JMP DRAW