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

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

ALGORITHM

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 negative numbers.
5. Load the value from array to a temporary register.
6. Compare the value with zero
• If zero flag is set, increment the register Rd.
• Else decrement the counter register and jump to step 5.
7. Repeat steps 5-6 till counter value becomes zero
8. Stop

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

CODE

      AREA program,CODE,READONLY
      ENTRY
      LDR R1,=array       ; Storing base address of array
      MOV R2,#0X09        ; Initializing counter
lbl   AND R0,[R1],#4      
      CMP R0,#00          ; Comparing with zero
      ADDMI R3,R3,#01     ; R3 register will have count of number of negative numbers.
      SUBS R2,R2,#01
      BPL lbl
array DCD  0x11223343, -0x12345672, 0x002917BD3, -0x00000A01, -0x62398746, 0xAB56E3CE, -0x0A761AC7, 0x623ABC46, -0xAB86E3BD, 0x0A762DE8,  
      END