Write an LC3 assembly language program that counts the numbe

Write an LC-3 assembly language program that counts the number of 1s in the value stored in R0 and stores the result in R1. For example, if R0 contains 0001001101110000, then R1should store the value 6.

Solution

.ORIG x3000

08.;initialise the registers we are using

09.LD R0, X     

10.AND R1, R1, #0   

11.AND R2, R1, #0

12.

13.;check if R0 is 0

14.LOOP    ADD R0, R0, #0   

15.BRz DONE

16.;count the bits

17.ADD R1, R1, #1

18.ADD R2, R0, #-1

19.AND R0, R0, R2

20.BRnzp LOOP

21.DONE    HALT

22.;X    .FILL 1370h   ; 0001001101110000 answer should be 6

23.;X    .FILL x5555    ; 0101010101010101 answer should be 8

24.X    .FILL xEEBB    ; 1110111010111011 answer should be 12

25.;X    .FILL x882    ; 0000100010000010 answer should be 3

26.;X    .FILL xFFFF    ; 1111111111111111 answer should be 16

28..END