Due date: See Canvas

0. Preparation

• Make a assignment sub-directory and copy the prepared files:

  mkdir ~/cs355/hw3 cp /home/cs355001/Handouts/hw3/* ~/cs355/hw3

  You will copy these files:

  basic.h - the commonly used circuit components in the CS355 assignments Full_Adder aa c_in a b | c_out sum; // A full-address Decoder2x4 aa c[1..0] | s[3..0]; // A 2x4 decoder You can use the Full_Adder and the 2x4 decoder components in this assignment help-ALU - the simulation program file to test the ALU circuit It creates switches and probes to help you test the ALU16 circuit (macro) that you must make in this assignment help-SHIFT - the simulation program file to test the SHIFTER circuit It creates switches and probes to help you test the SHIFTER16 circuit (macro) that you must make in this assignment alu-shf.h - Skeletal assignment file - contains the circuits (macro definitions) that you must make for this assignment

  You only need to edit the alu-shf.h file and turn it in for this assignment.

1. Assignment Description and new features in EDiSim used in assignment

This assignment reinforces the material in Chapter 3 of the CS355 Syllabus.
Read Chapter 3 of the lecture notes online at this link if you have problem designing the circuits: click here
The ALU was discussed here: click here
The Shifter was discussed here: click here

In this assignment, you will design and implement two components for your computer, which are:

a 16 bit ALU               a 16 bit Shifter

Both circuits are implemented as macros, so you will be writing two macros for this assignment.

New feature of EDiSim used in this assignment:

In this assignment, we will use the array notations for signals and use the short-hand notation to avoid writing out all 32 signal variables !!!

Information that you will need for this assignment:

How to define user-defined components as macros: click here . Array notation for signals and its short-hand notation: click here .

You have used macros in assignment 2; I have included the link to macros in case you need a refresher.

Please read the write ups on how to use array notation in EDiSim above.

2A. Assignment Assignment - part 1: make a 16 bit ALU circuit (as a macro)

• Write a macro called ALU16 that defines a 16-bit ALU circuit.

  Note:

  The ALU in the CS 355 assignment is different from the ALU that was demonstratred in class !!! (It will be constructed in a similar way, but the functions are slightly different) So be careful not to be confused with the CPU that I demonstrated in class !!!

  The ALU16 macro header is like this (and I have written it in the alu-shf.h assignment file:

  Define ALU16 a[15..0] b[15..0] c[1..0] | s[15..0] N Z; /* Complete the 16 bit ALU circuit here */ Endef;

  The inputs of the ALU16 circuits are:

  a[15..0] = the first (16 bit) binary number b[15..0] = the second (16 bit) binary number c[1..0] = two bits control signals to select the ALU operation Selection scheme for the ALU operations are: c[1] c[0] Function --------------------------------------------------- 0 0 Output = sum of the input numbers 0 1 Output = AND (a AND b bitwise and) 1 0 Output = first input a (s = a) 1 1 Output = Not of first input a (s = not a)

  The output signal variables are as follows:

  s[15..0] = 16 bit result of the selected operation N = the negative flag N=1 if the 16 bits binary number s[15..0] is a negative value (i.e., the left-most bit is equal to 1), otherwise N=0. Z = the zero flag Z=1 if the 16 bits binary number s[15..0] is equal to 0000000000000000 (i.e., the all bits are equal to 0), otherwise Z=0.

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  After you have written the ALU16 macro in the file alu-shf.h, you can test the ALU16 circuit using this command:

  /home/cs355001/bin/cs355sim help-ALU

  The test circuit (help-ALU) will look as follows:

  You can interact with the help-ALU test circuit as follows: Use the following keys to change the first input (binary) number: 1 2 3 4 q w e r a s d f z x c v Use the following keys to change the second input (binary) number: 8 9 0 - u i o p h j k l b n m , Use the following keys to change the function selection control signals: 6 7 Check whether the output value and the flags are computed correctly !!! You can observe the correct behavior by running this program and use the above instructions to interact with the circuit: /home/cs355001/Solutions/hw3-ALU

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• Comment:

  Just like the CPU discussed in class, you should first write a One_Bit_ALU component that do the specified computations given in Section 3 on 1-bit binary numbers. Then, use the One_Bit_ALU component to build the ALU16 component.

  NOTE:

  There is Decoder2x4( ) component in basic.h that you can use to implement the ALU There is FULL_Adder( ) component in basic.h that you can use to implement the ALU

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2B. Assignment Assignment - part 2: make a 16 bit Shifter circuit (as a macro)

• Write a macro called SHIFTER16 that implements a 16-bit shifter circuit.

  The macro header is as follows:

  Define SHIFTER16 a[15..0] c[1..0] | s[15..0]; /* Complete the 16 bit shifter circuit here */ Endef;

  The input parameters of the shifter circuit are as follows:

  a[15..0] = the (16 bit) binary number c[1..0] = two bits control signals to select the Shifter operation Selection scheme: c[1] c[0] Function ------------------------------------------------- 0 0 No shift (output = input) 0 1 Shift right 1 bit position 1 0 Shift left 1 bit position 1 1 Not used (output all 0)

  The output signals of the SHIFTER16 circuit are as follows:

  s[15..0] = 16 bit result of the selected shift operation

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  After you have written the SHIFTER16 macro in the file alu-shf.h, you can test the SHIFTER16 circuit using this command:

  /home/cs355001/bin/cs355sim help-SHIFT

  The test circuit (help-SHIFT) will look as follows:

  You can interact with the help-ALU test circuit as follows: Use the following keys to change the input (binary) number: 1 2 3 4 q w e r a s d f z x c v Use the following keys to change the function selection control signals: 6 7 Check whether the output value is computed (= shifted) correctly !!! You can observe the correct behavior by running this program and use the above instructions to interact with the circuit: /home/cs355001/Solutions/hw3-SHIFT

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• Important:

  Both macros (ALU16 and and SHIFTER16) must be store in the skeleton assignment file named "alu-shf.h" (provided in the handouts)

3. Skeleton assignment file alu-shf

• The skeleton assignment file for hw3 is: alu-shf.h

• You must use the alu-shf.h file to implement the ALU16 and the SHIFTER16 components:

  /* --------------------------------------------------------------------- Skeleton assignment file alu-shf.h --------------------------------------------------------------------- */ /* ------------------------------------------------------------------------ THIS CODE IS MY OWN WORK, IT WAS WRITTEN WITHOUT CONSULTING A TUTOR OR CODE WRITTEN BY OTHER STUDENTS - your name ------------------------------------------------------------------------ */ Define ALU16 a[15..0] b[15..0] c[1..0] | s[15..0] N Z; /* Complete the 16 bit ALU circuit here */ Endef; Define SHIFTER16 a[15..0] c[1..0] | s[15..0]; /* Complete the 16 bit shifter circuit here */ Endef;

  because:

  The provided circuit test environment program files will include the file alu-shf.h

  Complete the assignment by writing the ALU16 and SHIFTER16 macros.

  You can make and use other macros to help you define the ALU16 and SHIFTER16 macros. Put these macros in the alu-shf.h file.

4. New and old features of EDiSim that you need to know to do the assignment

• Array notation for signals

  In this assignment, you will be using arrays of signals (This topic would have been discussed in class). You can find information of array of signals here: click here

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• Defining/using your own components

  You have already used this feature in assignment hw2 In case you need to find information on how to define and use user-defined components, the page is here: click here

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• Components in basic.h

  The following components in basic.h can be helpful (and used) in this assignment: Full_Adder: a full adder circuit (that you have used in assignment 2) Decoder2x4: a 2-by-4 decoder circuit.

5. Turn in

Turn in your "alu-shf.h" file that contains the ALU16 and the SHIFTER16 components as assignment hw3 with the following command:

cd ~/cs355/hw3 /home/cs355001/turnin alu-shf.h hw3

6. Extension requests

• 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 hw3

Students will be graded partially on the basis of their programming assignments. These programming assignments are to be treated as examinations, and are expected to be your individual work. While discussions with other students in the course may be permitted or encouraged by your instructor, you should write your program yourself. The mathlab representatives are available to explain error messages, discuss briefly technical details with which you may not be familiar, and give short suggestions as to how you might detect logic errors. The reps should not, however be asked to write part or all of your program. Your instructor (and any teaching assistants assigned to the course) will be glad to help you to the extent that he or she feels reasonable.

Submissions based on other students solutions in prior offerings of the course specifically violate these guidelines, as do submissions prepared with the help of an outside "tutor".

You should take precautions to protect the confidentiality of your work: preserve the secrecy of your password, do not make files or directories sharable, pick up your printouts promptly and dispose of printouts where they will not tempt other students. All work should be done either in the class directory of your ITD account (preferred) or in your "priv" directory (only if you do not have a class directory).

All submissions should include a comment statement near the top of the program of the form:

THIS CODE IS MY OWN WORK, IT WAS WRITTEN WITHOUT CONSULTING A TUTOR OR CODE WRITTEN BY OTHER STUDENTS - your name

Cases of apparent plagiarism or collusion will be referred to the Honor Council.