Computer Organization Lab 06

CSCI 2500 — Computer Organization
Lab 06 (document version 1.2)
ˆ This lab is due by the end of your lab session on Wednesday, October 9, 2019.
ˆ This lab is to be completed individually. Do not share your code with anyone else.
ˆ You must show your code and your solutions to a TA or mentor to receive credit for each
checkpoint.
ˆ Labs are available on Mondays before your lab sessions. Plan to start each lab early and
ask questions during office hours, in the discussion forum on Submitty, and during your lab
session.
1. Checkpoint 1: For the first checkpoint, download the bit.s MIPS code example from
Submitty. Understand how the code works to produce the output below:
--------------x-----------------
-x-----------xxx----------------
-xx----------x--x---------------
x--x---------x---x--------------
x---x--------x---x--------------
x----x-------x----xxxxxx--------
x-----x------x----------xx------
x------xx---x--xx--------xxxxxxx-----x---xx--xxxx------------xx
-x---x---xx----xx---------xxxxx-
--x--x--x---x-----x---xxxx-x----
---x-x-x--------------xxxx-x----
xxx--xx---------xxxx------x-----
x---x--x---------xx----x--x-----
-x---x-x-----------------x------
--x--x-x----------------xx------
---x-xx-------------------xx----
----xx-----------------xx---x---
----x-----------------x--x---x--
---x-----------------x----xxxx--
--x-------------------x---------
--x--------------------x--------
--x-----xxxxxxxx-------x--------
---x--xx--------xx----x---------
---x--x-----------x----xx-------
--xxxx-------------xxxxxxxx-----
Modify the given code to eliminate the “j merge” instruction in the printbit procedure. In
other words, revise the procedure to use only one branch instruction.
To receive credit for this checkpoint, you need to show both your code revision and successful
output.
2. Checkpoint 2: Similar to Checkpoint 1, revise the bitcount procedure in bit.s to eliminate
the beq instruction. More specifically, you can only use the one bne instruction and the one
jal instruction; no other branch or jump instructions are allowed.
Try running your code using the hexadecimal words shown in the lab06a.txt and lab06b.txt
files available in Submitty.
And to test, add a syscall to print_int to display the return value (i.e., temporary register
$t0) before you print the newline and return.
To receive credit for this checkpoint, you need to show both your code revision and successful
output.
3. Checkpoint 3: For the third checkpoint, make a copy of the revised bit.s code, then modify
this code as described below.
Currently, this code displays each 32-bit word of the given data on a line by itself, i.e., one
word per line. Extend the bitcount procedure to display n words per line, where n is specified
as the third argument to bitcount in register $a2.
Further, to allow for multiple words, instead of passing the word to be displayed in $a0, pass
in the address of the data in $a0. This will also require a change in main.
Test your code by setting $a2 to 1. Then test your code using the lab06b.txt file with $a2
set to 2. What does your output look like?
As above, to receive credit for this checkpoint, you need to show both your code revision and
successful output.
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