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.

6666

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
200D 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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