Write an ARM Cortex M$3$ assembly code which determines positive, and negative numbers in a series of signed $32-$bit numbers. The number of elements in the array is defined by variable LENGTH and the start address of the array with START label. Your code should place the number of negative elements in register R$7,$ the number of zero elements in register R$6$ and the number of positive elements in R$5.$ Show how your code executes step$-$by$-$step using line comments.

Example: After execution R$5=3,$ R$6=1,$ R$7=2$