.arm
.text
.global main

main:

STMDB R13!, {R0-R12, R14}

LDR R1, =Values
LDR R2, =Const

MOV R11, #5

MOV R3, #0

Loop:

BL Subrtn

ADD R1, R1, #3

ADD R3, R3, #1
CMP R3, #4

BLO Loop

LDMIA R13!, {R0-R12, PC}

Subrtn:
STMDB R13!, {R4-R10}

LDRB R4, [R1]
LDRB R5, [R2]
MUL R6, R4, R5

LDRB R4, [R1, #1]
LDRB R5, [R2, #1]
MUL R7, R4, R5

LDRB R4, [R1, #2]
LDRB R5, [R2, #2]
MUL R8, R4, R5

ADCS R9, R6, R7
SUB R9, R9, R8

MUL R10, R9, R11
MOV R0, R10, ASR #6

LDMIA R13!, {R4-R10}

MOV PC, LR

.data
Values:
.byte 0x02, 0x03, 0x04
.byte 0x10, 0x05, 0x06
.byte 0x0B, 0x02, 0x0D
.byte 0x01, 0x0C, 0x08

Const:
.byte 0x04, 0x07, 0x05