Assn8Soln - CDA 3101 Assignment 8 Due in class on Thursday...

CDA 3101 Assignment 8
Due in class on Thursday, Nov. 30
Turn hardcopy in class, stapled, with your name and “CDA 3101 Assignment 8”
clearly written on it.
Important: For some of the problems below, I have provided figures (Figures 5.28, and
5.38 from the textbook) that you need to make additions/changes to. Use a ruler and a
RED pen to make any changes/additions to these figures, so that the changes are clearly
visible. In case, you make a mistake, I suggest you start with a clean figure. Also, clearly
write (in a numbered list) what changes/additions you have made to the figures and why
(Please feel free to use extra pages for this).
1. (22 points) Simulate on the multi-cycle path in Fig. 5.28 of the textbook (and using
the FSM in Fig. 5.38 of the textbook) the “beq $t0, $t1, label” instruction with $t0 =
$t1 = ABCDEF01
16
, label being the 5 instructions above beq, and the instruction
address = 0x00400040. Do this by filling in the following for each of the cycles it
takes to complete beq (you can put X for don’t know/don’t care). Provide
justification for each value you write below.
Cycle 1 Cycle 2 Cycle 3
PC 00400040
16
00400044
16
since
the PC is always
incremented by
4 bytes after the
first cycle.
00400044
16
since
nothing changes
the PC in the
second cycle since
PCWrite is false.
The branch
address doesn’t
make it in until the
rising edge of the
4
th
clock cycle.
Data port on
MEM
1109FFFA
16
X since
MemRead is 0,
and thus no data
is being read.
X since MemRead
is 0, and thus no
data is being read.
IorD 0 from FSM. ..we
do indeed want to
select the address
from the PC to get
an instruction
X from FSM
since it isn’t
listed, and we
don’t care what
address we send
to memory
because we’re
not using
memory
X from FSM for
same reasons as
cycle 2

IR X since the IR
doesn’t get written