Problem
Write a program for 8051 microcontroller to unpack a number stored in memory location 30h. Store the lower nibble in 31h and higher nibble in 32h.
Algorithm
Step 1: Load the number in accumulator.
Step 2: Mask the lower nibble to unpack.
Step 3: Store the unmasked lower digit in internal memory location.
Step 4: Load the number in accumulator again.
Step 5: Mask the higher nibble to unpack.
Step 6: Rotate 4 times or SWAP.
Step 7: Store the unmasked higher digit in internal memory location.
Step 8: Stop.
Flowchart
Program
MOV A, 30H ; Load the number from 30h in accumulator.
ANL A, #0FH ; AND content of accumulator with 0Fh to mask lower nibble.
MOV 31H, A ; Store the lower digit in 31h memory location.
MOV A, 30H ; Load the number in accumulator again.
ANL A, #0F0H ; AND content of accumulator with 0F0h to mask higher nibble.
SWAP A ; Exchange lower and higher nibble
MOV 32H, A ; Store the higher digit in 32h memory location.
LOOP: AJMP LOOP ; Stop.
