Program to find the Square of a number using a look-up table in 8085 Microprocessor

MicroprocessorMicrocontroller8085

We write an 8085 assembly language program for finding the square of a single digit (0 to 9) using a look-up table for displaying a number and its square in the address field.

FILE NAME MYSQR.ASM

ORG C100H

X: DB 00H, 01H, 04H, 09H, 16H, 25H, 36H, 49H, 64H, 81H

ORG C000H

CURAD: EQU FFF7H
UPDAD: EQU 06BCH
IBUFF: EQU FFFFH

MVI A, 0EH ; Load A with 0000 1110B
SIM ; Unmask RST5.5 i.e. enable keyboard interrupt.

; The next 4 instructions check if a key is pressed. If a key is
; pressed, RST5.5 pin gets activated but does not interrupt the 8085
; as it is in DI state. But RIM instruction execution reveals that
; RST5.5 is pending. In such a case, the loop is exited.
AGAIN:
DI
RIM
ANI 00010000B
JZ AGAIN ; Stay in this loop till a key is pressed

EI
NOP ; RST5.5 interrupts the 8085 now. Only after NOP is
; executed, interrupt system is enabled.
; So control is transferred to RST5.5 ISS. Details of this ISS
; is discussed in a later chapter when Intel 8279 chip is discussed.
; Execution of this ISS results in location IBUFF getting loaded
; with code of key pressed. Then the control is passed on to the
; program segment shown below.

LDA IBUFF
CPI 0AH
JNC AGAIN ; If code is >= 0AH, jump to AGAIN.

LXI H, X ; Point HL to the beginning of the look up table.
MOV L, A ; Load L from A. Thus, point HL to the location which
; contains the square of the number input by the user.
MOV A, M ; Load A with the square of the number.
MOV H, L ; Load H with the number whose square is desired.
MOV L, A ; Load L with the square of the number.

SHLD CURAD
CALL UPDAD ; Display the number and its square.
JMP AGAIN ; Jump to read the next value from the keyboard.
raja
Updated on 30-Jul-2019 22:30:25

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