1/ You are required to write a MARIE assembly program to implement unsigned inte

Question

1/ You are required to write a MARIE assembly program to implement unsigned integer multiplication (you are free to decide in which memory locations the 2 numbers are stored and where to store the result). You should evaluate the correctness of your program testing it with at least 3 pairs of numbers covering at least the cases: A*B=B*A (remember that the multiplication is commutative) and 1*A=A.

- Change your program to perform signed integer multiplication, test it with at least 3 pairs of numbers covering the cases: ++; +-;

Explanation / Answer

org $800

M rmb 4 ; reserved to hold the multiplicand

N rmb 4 ; reserved to hold the multiplier

P rmb 8 ; reserved to hold the product

org $1000

ldd M+2 ; place ML in D

ldy N+2 ; place NL in Y

emul ; compute MLNL

sty P+4 ; save the upper 16 bits of the partial product MLNL

std P+6 ; save the lower 16 bits of the partial product MLNL

ldd M ; place MH in D

ldy N ; place NH in Y

emul ; compute MHNH

sty P ; save the upper 16 bits of the partial product MHNH

std P+2 ; save the lower 16 bits of the partial product MHNH

ldd M ; place MH in D

ldy N+2 ; place NL in Y

emul ; compute MHNL

; the following seven instructions add MHNL to memory locations P+2~P+5

addd P+4 ; add the lower half of MHNL to P+4~P+5

std P+4 ;

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.