Question

E 2.12 Write a program to compute the average of the square of all elements of an array with 32 8-bit unsigned numbers. the array is stored at $1000-$101F. Store the results at $1020-$1021.

Answer 1

The program is commented array elements is not entered, the addresses are mentioned

N: equ 32 ;array count

org $1000 ;starting address of the elements

array: dw -elements- from $1000 - $101F

sum: rmb 4 ;array sum

i: rmb 1 ;array index

org $1500 ;starting addr of program

ldaa #0

staa sum ;initiallize sum to 0

staa mul ;

staa i ; intialize loop counter zero

loop ldab i ;B

cmpb #N ;is i=N?

beq done ;if i=N then branch to label ‘done’

ldx #array ;use index register X as pointer to the array , X=$1000

abx ;X <-X+B = X+I, to compute the address of current element

ldd 0,x ;place array[i] in D

ldy 0,x ;D

emuls ; perform signed multiplication D*D

std mul ;

sty mul ;

ldd 0,x ; D <- mul , D is set to array[i]*array[i]

addd sum+2 ;D=D+sum

std sum+2

ldaa #0

adca sum+1 ;propagating carry to msb

staa sum+1

inc i ;moving to next element

inc I

bra loop

$1020 - $1021

ldd sum ;load the dividend into D

ldx N ;load the divisor into X

idivs ; perform signed division

stx $1020 ;storing the quotient

std $1021 ;storing the remainder

done swi

end