This problem explores two strategies for sequentially accessing the elements of a word array

to implement an assembly language subroutine Total according to these specifications.

$$ Accepts a pointer to an array of signed words in register R$1.$

$$ Accepts a word value in register R$2,$ which indicates the number of array elements.

$$ Returns the total, $($i$.$e$.,$ sum$),$ of array elements in register R$0.$

$$ On return, preserves contents of all registers, other than return result register and PSR$.$

a$.$

Write an assembly language subroutine to implement Total as follows.

$$ Use displacement mode addressing to access each element: $[$R$1,$ #$0].$

$$ Manually update the array pointer to access the next element: ADDS R$1,....$

$$ Use a down counter to control iteration $($count from R$2$ down to $0).$

b$.$ Write an assembly language subroutine to implement Total as follows.

$$ Use the autoincrement form of load multiple LDM to access each array element and

update the array pointer in one instruction.

$$ Use a down counter to control iteration $($count from R$2$ down to $0).$