Ive understood the first part of this lab and have gotten all the answers. i just need help on answers…
Ive understood the first part of this lab and have gotten all the answers. i just need help on answers #21 through #27. Im pretty lost on this….
we are using the “
Brookshear machine simulator”
Experiment 2
In this Experiment you will learn about the use of the JUMP instruction. The following
program contains both conditional instructions and a loop.
memory memory
address content comment
F0 20 ;LOAD R0 with 00
F1 00
F2 21 ;LOAD R1 with 01
F3 01
F4 23 ;LOAD R3 with 03
F5 03
F6 B3 ;JUMP to FC if R3 equals R0
F7 FC
F8 50 :ADD R0, R1 into R0
F9 01
FA B0 ;JUMP to F6
FB F6
FC C0 ;HALT
FD 00
Step 1. Either re-start the simulation program, or select C to clear both main memory
and registers of any previous values. Then select option M to enter the program.
Check that the program has been placed correctly in memory. © Anthony W. Smith, 2014
CSCI 108: Survey of Computer Science
Lab 4: Introduction to machine code lab
Step 2. Select option P, and set the Program Counter to the address of the start of the
program
Step 3. Select option S to execute the program one step at a time. Record the value of
the PC after each step. (HINT: you should record 13 PC values including FC for the
HALT instruction.)
19. _________________________________________________________________
_________________________________________________________________
_________________________________________________________________
Step 4. How many times do we go round the loop?
20. _________________________________________________________________
_________________________________________________________________
_________________________________________________________________
_________________________________________________________________
_________________________________________________________________
Step 5. A JUMP instruction is said to be unconditional if a jump will occur every time
the instruction is executed.
21. the JUMP at address FA is an unconditional jump (T / F) _________________
Step 6. Say I erased the program from memory, then entered it again starting in location
A0. Two instructions would have to be changed for the program to work. Write down
the old instruction, the new instruction, and the new comment for each. (Check your
answers by entering the new program and running it until it terminates.)
22. old instruction #1 ___________________________________________________
23. new instruction #1 __________________________________________________
24. new comment #1 ___________________________________________________
25. old instruction #2 ___________________________________________________ © Anthony W. Smith, 2014
CSCI 108: Survey of Computer Science
Lab 4: Introduction to machine code lab
26. new instruction #2 __________________________________________________
27. new comment #2 ___________________________________________________