# How do I code the Fibonacci sequence LMC?

I was wondering if it was possible to create a program that creates the Fibonacci Sequence in "Little Man Computer".

The program would output in the letter boxes the individual numbers of the sequence. The only input made would be asking the user how high it would like the sequence to go. For example if I input "20" it would only go up to to number 13.

Any help would be greatly appreciated,

Isaac.

## Answers

Source: link

INP STA N LOOP LDA A SUB N BRP ENDLOOP LDA A OUT LDA B ADD A STA ACC LDA B STA A LDA ACC STA B BRA LOOP ENDLOOP HLT A DAT 0 B DAT 1 N DAT ACC DAT

The fibonacci series can be printed in the LMC in the following manner:

INP STO n #number of terms LDA one OUT loop LDA fib #THE MAIN LOOP THAT PRINTS FIBONACCI NUMBERS STO temp2 ADD temp STO fib LDA temp2 STO temp BR check check LDA n #LOOP TO KEEP A TRACK OF NUMBER OF TERMS BRZ halt SUB one STO n BRZ halt LDA fib OUT BR loop halt HLT n DAT 000 fib DAT 001 temp DAT 001 temp2 DAT 000 one DAT 001

Explanation: The program first asks for an input n, the number of terms to be printed.Then the loop starts running - it will print the default value of variable fib, which has been set to 1. The value of fib is stored in another variable temp2, and the variable temp is used to record the previous value of fib so that the numbers are added correctly and a correct sequence is obtained. The loop controls the values of fib, temp and temp2 as the number of terms are increased.

The program then checks if the number of terms required have been printed and decrements the value of n. If n=0 it means that the required number of terms has been reached and the program halts. If n is not zero, the loop continues till n=0.

**Though there might me more efficient methods, however this one works correctly and uses a pretty less number of mailboxes which makes it quite efficient.