ARM Assembly code to find number of even numbers in an array

Let’s see how write a ARM assembly code to find number of even numbers in an array.

ALGORITHM

1. 1. Start
   2. Load the base address of array.
   3. Initialize a counter register to number of elements in array.
   4. Initialize a register(Rd) to zero to store number of even numbers.
   5. Load the value from array to a temporary register.
   6. AND the value in temporary register with 0x01.

1. • If zero flag is set, increment to register Rd.
   • Else decrement the counter register and jump to step 5.
2. Repeat steps 5-6 till counter value becomes zero
3. Stop

Here is a example code to find number of even numbers in an array. Note: initialize the array at the end of program without fail, before execution.

CODE

      AREA program,CODE,READONLY
      ENTRY
      MOV R0,#01          ; Storing 0x01 for AND operation
      LDR R1,=array       ; Storing base address of array
      MOV R2,#0X09        ; Initializing counter
lbl   AND R0,[R1],#4      ; 'AND'ing to check whether number is odd or even
      ADDEQ R3,R3,#O1     ; R3 register will have count of number of even numbers.
      SUBS R2,R2,#01
      BPL lbl
array DCD  0x11223344, 0x12345671, 0x002917343, 0x00000001, 0x62398746, 0xAB56E3CD, 0x0A761BC7, 0x623ABC46, 0xAB86E3BD, 0x0A761DE8,  
      END