$3.(40$ pts$)$ Write an ARM Cortex M$3$ assembly code that calculates and determines which element in an array of $32-$bit numbers has the largest number of bits set. The length of the series is defined by variable LENGTH held in R$2$ and the series starts with the START label. Store the value with the most bits set in the R$1$ register. Show how your code executes step$-$by$-$step using line comments.

Example: After execution R$1=0$x$29856779$