Decimal subtraction of two 8-bit numbers

Program Name

Write a Assembly Language Program for Decimal subtraction of two 8-bit numbers.

Theory

Instruction Mnemonic	Operand	Comments
LDA	8100	load the first i/p from 8100 to Accumulator
MOV	B,A	move the content of accumulator to reg.B
MVI	A,99H	Move immediately 99H to accumulator (largest two digit decimal number )
SUB	B	subtract from the accumulator, the contents of reg.B to get the 9's complement
INR	A	increment the content of accumulator to get 10's complement
		(Add 1 to 9’s complement to get 10’s complement)
MOV	C,A	move accumulator contents into reg.C
LDA	8101	load the second i/p of sub into accumulator through memory 8101
ADD	C	add the contents of accumulator
		(-ve number ) with reg.C
DAA		decimal adjust after addition
		convert the content of accumulator into decimal format after addtion
STA	8102	store the result(content of accumulator) at 8102
HLT		stop

Program Code


LDA	8100
MOV	B,A
MVI	A,99H
SUB	B
INR	A
MOV	C,A
LDA	8101
ADD	C
DAA	
STA	8102
HLT

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