Problem:
Write a microprocessor 8085 program to find the square of a number from 0 to 9 using a table of squares. The number is at memory location 4150H and store the result at 4151H.
Assume that the square of numbers is stored in the lookup table starting form 4125H.
Algorithm:
- Initialize H-L pair to point Look up
- Get the data.
- Check whether the given input is less than 9.
- If yes go to next step else halt the program.
- Add the desired address with the contents of accumulator.
- Store the result.
Program:
LXI H, 4125H ; Initialize Look up table address
LDA 4150H ; Get the data
CPI 0AH ; Check input > 9
JC Lookup ; if yes error else jump to Lookup
MVI A, EEH ; Error Indication
STA 4151H ; Display error message
HLT ; Terminate the program
Lookup: MOV C, A ; Add the 0-9 value in C register
MVI B, 00H ; Initialize B=00H
DAD B ; HL (memory address) + B-C (a number)
MOV A, M ; Copy the contents of memory to accumulator
STA 4151H ; Store the result
HLT ; Terminate the program
Lookup Table:
4125 | 00 |
4126 | 01 |
4127 | 04 |
4128 | 09 |
4129 | 16 |
4130 | 25 |
4131 | 36 |
4132 | 49 |
4133 | 64 |
4134 | 81 |
Sample Example:
Input: 4150H: 08
Output: 4151H: 64
Input: 4150H: 14
Output: 4151H: EE (Error Indication)
