Please carefully read the following instructions before attempting assignment.
Rules for Marking
It should be clear that your assignment would not get any credit if:
The assignment is submitted after the due date.
The submitted assignment does not open or file is corrupt.
Strict action will be taken if submitted solution is copied from any other student or from the internet.
1) You should concern recommended books to clarify your concepts as handouts are not sufficient.
2) You are supposed to submit your assignment in .doc format. Any other formats like scan images, PDF, zip, rar, bmp etc will not be accepted.
Note:
No assignment will be accepted after the due date via email in any case (whether it is the case of load shedding or internet malfunctioning etc.). Hence refrain from uploading assignment in the last hour of deadline. It is recommended to upload solution file at least two days before its closing date.
For any query, feel free to email at:
cs401@vu.edu.pk
Question Statement:
An assembly program is given for printing three different strings on screen with the help of BIOS video services. Students are required to add the missing code in order to perform the following operations.
After running the code in command prompt, subsequent keystrokes should result in:
Clear screen --------------------------------------------------------------------------------------------1st keystroke
Display ID (yellow on black background) on screen’s top ---------------------------------2nd keystroke
Display Name (red on white background) on screen’s middle line ---------------------3rd keystroke
Display University Name (blue on yellow background) at the bottom of screen -- 4th keystroke
[org 0x100]
jmp start
ID: : Data label for Student’ ID
Name: ; Data label for Student’s name
University Name: ; Data label for University’s name
clrscr: push es
push ax
push cx
push di
mov ax, 0xb800
mov es, ax
xor di, di
mov ax, 0x0720
mov cx, 2000
cld
rep stosw
pop di
pop cx
pop ax
pop es
ret
printstr: push bp
mov bp, sp
push es
push ax
push cx
push si
push di
push ds
mov ax, [bp+4]
push ax
call strlen
cmp ax, 0
jz exit
mov cx, ax
mov ax, 0xb800
mov es, ax
mov al, 80
mul byte [bp+8]
add ax, [bp+10]
shl ax, 1
mov di,ax
mov si, [bp+4]
mov ah, [bp+6]
cld
nextchar: lodsb
stosw
loop nextchar
exit: pop di
pop si
pop cx
pop ax
pop es
pop bp
ret 8
strlen: push bp
mov bp,sp
push es
push cx
push di
les di, [bp+4]
mov cx, 0xffff
xor al, al
repne scasb
mov ax, 0xffff
sub ax, cx
dec ax
pop di
pop cx
pop es
pop bp
ret 4
start:
Code required from students
Best of luck!
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