8085 program to generate Fibonacci series

Problem – Write an assembly language program in 8085 microprocessor to generate Fibonacci series.

Example – Assume Fibonacci series is stored at starting memory location 3050.

Note – This program generates Fibonacci series in hexadecimal numbers.

Algorithm –

1. Initialize register H with 30 and register L with 50, so that indirect memory M points to memory location 3050.
2. Initialize register B with 00, register C with 08 and register D with 01.
3. Move the content of B in M.
4. Increment M by 1 so that M points to next memory location.
5. Move the content of D in M.
6. Move the content of B in accumulator A.
7. Add the content of D in A.
8. Move the content of D in B.
9. Move the content of A in D.
10. Increment M by 1 so that M points to next memory location.
11. Move the content of A in M.
12. Decrements C by 1.
13. Jump to memory location 200C if ZF = 0 otherwise Halt the program.

Program –

MEMORY ADDRESS	MNEMONICS	COMMENT
2000	LXI H, 3050	H <- 30, L <- 50
2003	MVI C, 08	C <- 08
2005	MVI B, 00	B <- 00
2007	MVI D, 01	D <- 01
2009	MOV M, B	M <- B
200A	INX H	M <- M + 01
200B	MOV M, D	M <- D
200C	MOV A, B	A <- B
200C	ADD D	A <- A + D
200E	MOV B, D	B <- D
200F	MOV D, A	D <- A
2010	INX H	M <- M + 01
2011	MOV M, A	M <- A
2012	DCR C	C <- C – 01
2013	JNZ 200C	Jump if ZF = 0
2016	HLT	END

Explanation – Registers A, B, C, D, H, L are used for general purpose.

1. LXI H 3050: assigns 30 to H and 50 to L.
2. MVI B, 00: assigns 00 to B.
3. MVI C, 08: assigns 08 to C.
4. MVI D, 01: assigns 01 to D.
5. MOV M, B: moves the content of B in M.
6. INX H: increment M by 1.
7. MOV M, D: moves the content of D in M.
8. MOV A, B: moves the content of B in A.
9. ADD D: add the content of D and A. Store the result in A.
10. MOV B, D: moves the content of D in B.
11. MOV D, A: moves the content of A in D.
12. INX H: increment M by 1.
13. MOV M, A: moves the content of A in M.
14. DCR C: decrements C by 1.
15. JNZ 200C: jump to memory location 200C if ZF = 0.
16. HLT: stops executing the program and halts any further execution.

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