Write an ASM program to count number of zeros and ones?

Code:

AREA ZEROS_ONES, CODE
ENTRY
LDR R0,= VAR
MOV R1, #32
LDR R2, [R0] Z1MOVS R2, R2, LSL#1
ADDCS R3, R3, #1
ADDCC R4, R4, #1
SUBS R1, R1, #1
BNE Z1
STOP B STOP
VAR DCD 0X01010101
END