Question

For the following answer the questions below: ORG 300 LDA ADS STA PTR LDA NBR STA CTR CLA INC LOP. STA PTR 1 ISZ PTR ISZ CTR BUN LOP HLT ADS, HEX 800 PTR, HEX0 NBR, DEC-200 CTR. HEX0 END Briefly describe the task performed by the code above? What is the content of the following memory locations after the execution of the program: What is the number of iterations in program above?

Answer 1

Answer

1
Below is what each statement of the code means:

ORG 300   #code starts at address 300
LDA ADS   #load in accumulator the content of ADS, i.e. 800
STA PTR   #store the content of accumulator in address HEX 0
LDA NBR   #load in accumulator the content of NBR, i.e. DEC -200
STA CTR   #store the content of accumulator in address HEX0
CLA #clear accumulator
INC #increament accumulator, carry is stored in E
LOP, STA PTR I   #store in mem loc HEX 0
ISZ PTR   #increase mem loc by 1, skip if PTR has 0
ISZ CTR   #increase mem loc by 1, skip if CTR has 0
BUN LOP   #branch unconditionally to LOP
HLT