- Make a assignment sub-directory
and copy the
prepared files:
mkdir ~/cs355/hw5 cp /home/cs355001/Handouts/hw5/* ~/cs355/hw5You will copy these files:
hw5.h - This file contains the machine instructions that you must write for assignment 5 Many other support files that construct a working CPU !!! DO NOT touch these files !!!
- This assignment is to reinforce
the encoding method used in
machine instruction.
Each bit in a machine instruction controls
some component inside the CPU.
You will learn how to set the bits in
a machine instruction to perform
certain computer instruction.
- In this assignment, you will write a number of machine instructions (in binary form) that accomplish certain effects specified by the assignment
- The format of the machine instruction has been
discussed in class.
This webpage contains the description of the
machine instruction:
click here
Each machine instruction is 32 bits long
- Each bit in the machine instruction controls a certain component in the datapath
- The meaning of
of the bits in
a machine instruction are
as follows (it has been explained in class):
- Refer to this
lecture note
on how each of the
bit in
a machine instruction is used to
control the CPU:
click here
- For this assignment,
you must write the following
ten (10) machine instructions
(as binary numbers) in the
assignment file hw5.h:
Memory Location machine instruction 0 Copy R8 to R0 (i.e.: mov r0, r8) 1 Copy MDR to R1 2 Add R6 and R8 and store result in R2 3 Add MDR and R9 and store result in R3 4 Left shift R9 and store result in R4 5 Right shift (R8+R9) and store result in R0 6 Left shift (NOT(MDR)) and store the result in R1 (NOT ≡ invert the bits) 7 Compute R8/2 and store the result in register R2 8 Compute 2*(R6 + R9) and store the result in R3 9 Compute 4*R9 and store the result in R4 I will describe how to write the machine instruction in the next section.
- Procedure:
- First, you must
determine the
correct
bit setting in
each machine instruction field
- Then, write these 32 bites out as a binary constant in the file hw5.h provided to you in this assignment
- First, you must
determine the
correct
bit setting in
each machine instruction field
- Example:
- Let's start with an empty
mirco-instruction:
- Suppose we
have determined that
we need to use the following
bit pattern to
control the
data path:
- You must first
form 4 groups of
8 bits:
- Therefore, you will write the following
4 binary numbers for
the machine instruction:
Writing binary numbers in C:
- You are in fact writing a binary number in C when you use
the prefix 0b
- The notation:
0b.......
denotes a binary number (= a number written in the binary number system) in C
- This is how to denote
numbers in other number systems in a C program:
0..... is a Octal number 0x.... is a Hexadecimal number 0b.... is a Binary number A number that does not start with 0 is a decimal number
- Let's start with an empty
mirco-instruction:
- You must store the machine instructions
in a ROM
(read only memory)
that is defined in the
skeleton assignment file
hw5.h
- The skeleton assignment file hw5.h has been copied to your assignment directory in the preparation step
Here is the initial content in the hw5.h program file that you must put the mirco-instructions:
/* ------------------------------------------------------------------ HW5 TODO: Write the binary number pattern for the 10 machine instructions specified in the homework assignmnet write up below. Each machine instruction is 32 bits or 4 bytes You can write each byte of the machine instruction in this format: 0bXXXXXXXX where X is 0 or 1 A number starting with 0b is treated as a binary number by the compiler To help you obtain the bit pattern, I have align the bit along with the meaning of each bit using the acronym below. (You need to read the acronym vertically !!!) You ONLY need to change the bits under: AMux, ALU, Shif, EnC, CCCC, BBBB, AAAA You DO NOT need to change the bits under: Cond, MBR, MAR, RD, WR, branch address Meaning of the bits: (to help you set the bits of the machine instr) Read the acronym vertically !!! |||||||| |||| VVVVVVVV VVVV ACCAASSM MRWE MooLLhhB ADRn unnUUiiR R C branch xdd ff CCCC BBBBAAAA address ------------------------------------------------------------------- */ /* instr. 0: */ 0b00000000, 0b00000000, 0b00000000, 0b00000000, /* instr. 1: */ 0b00000000, 0b00000000, 0b00000000, 0b00000000, /* instr. 2: */ 0b00000000, 0b00000000, 0b00000000, 0b00000000, /* instr. 3: */ 0b00000000, 0b00000000, 0b00000000, 0b00000000, /* instr. 4: */ 0b00000000, 0b00000000, 0b00000000, 0b00000000, /* instr. 5: */ 0b00000000, 0b00000000, 0b00000000, 0b00000000, /* instr. 6: */ 0b00000000, 0b00000000, 0b00000000, 0b00000000, /* instr. 7: */ 0b00000000, 0b00000000, 0b00000000, 0b00000000, /* instr. 8: */ 0b00000000, 0b00000000, 0b00000000, 0b00000000, /* instr. 9: */ 0b00000000, 0b00000000, 0b00000000, 0b00000000,Notice:
- There are 10 rows of
bits (they are all 00000000
initially)
- I have labeled the
bit positions with its
function in the
banner above the bits
- The left-most bit is labeled as AMux (because it control the A-bus multiplexor in the data path)
- The next 2 bits are marked as Cond (we don't use these 2 bits in CS355)
- The following next 2 bits are makred as ALU because they conrol the function that the ALU will perform.
- And so on...
- For assignment 5, you
ONLY need to change the bits under:
AMux, ALU, Shif, EnC, CCCC, BBBB, AAAA
- The following command is
used to construct and run the
test circuit for
hw5:
cd ~/cs355/hw5 // execute this command ONCE only in window bash ./run-hw5You will see the following circuit:
To check if the instructions that you have written is correct (or not):
- You will run the CPU so it will execute the instructions that you wrote in the addresses 0 - 9 !!!
- How to operate the
circuit:
- Use Function key F2 to
toggle the
line in the
circult !!!
This will help with the clarity
- Use the key b to
reset the circuit:
- Clear the registers R1, R2, R3, R4, and R5 to 0
- Set 4 phase clock to phase 1 (i.e. Phase[0] = 1)
You must have the reset toggled to 0 to allow the CPU circuit to run !!!
- Use the keys
0,
1,
2 and
3
to select an
address between
0 and 9
- The machine instruction selected will be shown on the upper-right hand corner
The select machine instruction can now be executed by:
- Toggling the key a (4 times)
When executing an machine instruction, make sure that:
- Reset = 0
- The 4 phase clock is at Phase[0] when you start executing the machine instruction (= start clicking on key a)
- Use Function key F2 to
toggle the
line in the
circult !!!
- The result of the
execution of the
machine instruction can be
view in the
registers (at the top-left)
in the circuit:
- Check if the correct register was updated with the correct value
- You can set up
a specific machine instruction
using this demo program I used in class:
/home/cs355001/demo/datapath/cs355-demo-dp2You can turn off the lines by pressing the F2 key.
Press the ' (= the quote key next to the ENTER key at the right of the keyboard) once to de-activate the RESET function.
To test a machine instruction:
- Set up the
machine instruction using the
keys:
- 1, 2, 3, 4, 5, 6, 7, 8, 9, 0
- q, w, e, r, t
- a, s, d, f
- h, j, k, l
- z, x, c, v, b, n, m, ','
- Then click 4 times up-and-down on the '/' key to similar 4 click signals to execute the selected machine instruction
- Set up the
machine instruction using the
keys:
- Turn in your hw5.h file
using the following command:
/home/cs355001/turnin hw5.h hw5
- Each assignment must be
turned in before the
specified dead line
(see class webpage for the
deadline)
- You can request upto 3 extensions
in the semester
without any penalties without
any questions asked
(A 4th extension request will be automatically denied --- personal emergencies and illiness with documentation will receive a "free" extension)
- To request an
extenion for this assignment,
us the following
command:
/home/cs355001/req-ext hw5