Question

1. consider the following program. interpret the program line by line. Get an idea what the program.
TOS EQU 0FEFEH
CPU 8086
ORG 0400H

SECTION CODE:
MAIN:
MOV SP, TOS
CALL INITIALIZATION
MOV BX, PATTERN
MOV AL, [BX]
JMP $

INITIALIZATION:
MOV WORD[03FCH], COUNTERISR
MOV WORD[03FCH], 0
MOV AX, 0
STI
RET

COUNTERISR:
OUT 0, AL
IRET

SECTION DATA:
PATTERN DB 255, 128, 170, 15, 240

Do the following:
Part a:
a) by following the program as above, determine what would be the pattern that should be displayed on the LEDs.
Answer:

b) change the special instruction in the above [BX+1]. Determine what would be the pattern that should be displayed on the LEDs.
Answer:

c) change the special instruction in the above [BX+2]. Determine what would be the pattern that should be displayed on the LEDs.
Answer:

d) change the special instruction in the above [BX+3]. Determine what would be the pattern that should be displayed on the LEDs.
Answer:

e) change the special instruction in the above [BX+4]. Determine what would be the pattern that should be displayed on the LEDs.
Answer:

Answer 1

Since the program does not provide the specific instructions for controlling the LEDs, it is not possible to determine the pattern that would be displayed on the LEDs accurately. The program only shows the initialization process and the structure of the program, but it does not contain the relevant instructions for controlling or changing the patterns on the LEDs.