8086 Program to mask lower nibble
11:30
Explanation :
·
Let the 8 bit number be in the AL register. We
have to mask the lower nibble, ie we have to separate the lower nibble. In the
result only MSB number should remain.
eg. : AL
= 5B H.
|
0101
|
1011
|
|
Logically AND with F0 H
|
1111
|
0000
|
|
0101
|
0000
|
= 50 H.
|
Result
= 50 H. B is masked
Display
the result.
ØØ Algorithm :
Step
I : Load the number in AL.
Step
II : Mask tower nibble i.e.
AND AL, 0F0 H.
Step
III : Display result.
Step
IV : Stop.
ØØ Flowchart : Refer
flowchart 3.
ØØ Program :
.model smallFlowchart 3
.data
a dw 0012H
.code
mov ax,
@data ; Initialize data
section
mov ds,
ax
mov ax,
a ; Load number1 in
ax
and al,
0f0h ; mask lower
nibble.Result in al
mov ch,
02h ; Count of digits to
be displayed
mov cl,
04h ; Count to roll by 4 bits
mov bh,
al ; Result in reg bh
l2: rol bh,
cl ; roll bl so that
msb comes to lsb
mov dl,
bh ; load dl with data
to be displayed
and dl,
0fH ; get only lsb
cmp dl,
09 ; check if digit is
0-9 or letter A-F
jbe l4
add dl,
07 ; if letter add 37H
else only add 30H
l4: add dl, 30H
mov ah,
02 ; Function 2 under
INT 21H (Display character)
int 21H
dec ch ; Decrement Count
jnz l2
mov ah,
4ch
int 21h
end
ØØ Result :
C:\programs>tasm
lownib.asm
Turbo
Assembler Version 3.0 Copyright (c) 1988, 1991 Borland International
Assembling
file: lownib.asm
Error
messages: None
Warning
messages: None
Passes: 1
Remaining
memory: 438k
C:\programs>tlink
lownib.obj
Turbo
Link Version 3.0 Copyright (c) 1987,
1990 Borland International
Warning: No
stack
C:\programs>lownib
10
C:\programs>
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