NMK206 - Computer Architecture

This course is Computer Architecture, offered by the Faculty of Electronics Engineering & Technology (FKTEN) for Electronic Engineering Technology programs.

Download ModelSim 20.1.1.720 (Intel FPGA Starter Edition) setup (SHA-1 checksum). Linux users can try this (SHA-1 checksum).

Video Guide(s)

YouTube Playlist

[20250323] Welcome to NMK206 info page (for 007 lab sessions only)!

[20250424] Soft reminder: Lab Assessment 1 @202500420-0800!

I am using Takahashi Method for these slides (Actually, I broke that method by adding diagrams and long codes because I think my students need them). You will find them hard to understand if you do not attend my sessions. So, that is the 'advantage' I gave to those who actually listen in class

• Lab Briefing Slides
• Intro to CAD Tools and HDL Slides Online Session (Video)
• Verilog Basics Slides Online Session (Video)
  • [Extra] Online Session (Video) (Partial... was stopped due to low number of students)
• Combinational Logic Slides (P1) Slides (P2) Slides (P3) Slides (P4) Slides (P5)
• Sequential Logic Slides (P1) Slides (P2)
• State Machine Slides
• Simple Digital System Slides

This is the coding rule that I impose on my students. You will be penalized during assessments if it is not adhered to.

1. One file for one module
   • RULE: 1 file 1 module
2. File name must be the same as module name
   • RULE: file name === module name (.v)
3. All circuit (module) must have a testbench (tb)
   • tb is a also module (so, separate file)
   • RULE: All module MUST have a testbench
   • RULE: Tb name === module name + _tb
4. Use Verilog95 module declaration
   • Port list contain names only (separate input/output declaration)
   • Port connection(s) MUST BE specified using ordered list
   • RULE: Port connection(s) by ordered list ONLY!
5. Modules for combinational logic should only use wire/assign statements
   • reg/always reserved for sequential logic and testbench modules
   • RULE: comb. logic use assign/wire only!
6. Only basic logic gates are allowed
   • Can only use AND/OR/INV in your logic implementation
   • XOR logic is allowed for lab project only
   • RULE: allowed operators AND, OR, INV
7. Assign statements can only have ONE binary operator
   • Multiple bitwise inverts (~) are ok (they are unary operators)
   • RULE: 2-input logic gates ONLY
8. ALL nets (wire/reg) MUST BE declared.
   • some compiler may allow using without declaration
   • for my assessments, they MUST BE declared
   • RULE: All signals @wire must be declared!

Complete template for a simple 4-bit processor core (as discussed during class) available here.

Here is an example code to utilize the carry/borrow signals of our add/subtract modules at ALU level. You may use this to create add-with-carry and subtract-with-borrow functions (hint: you need a selector signal to 'enable' the carry/borrow in signals {iC} and {iB}).

alu_flag_4b.v

module alu_4b (iS,iP,iQ,iF,oF,oY);
input[1:0] iS;
input[3:0] iP,iQ,iF;
output[3:0] oF,oY;
wire[3:0] oY;
wire iC, iB, oC,oB;
 
wire[3:0] tA0, tA1;
wire[3:0] tL0, tL1;
 
add_4b a_add (iC,iP,iQ,oC,tA0);
sub_4b a_sub (iB,iP,iQ,oB,tA1);
and_4b l_and (iP,iQ,tL0);
or_4b l_or (iP,iQ,tL1);
 
// separate flag bits for borrow and carry
assign oF = { 2'b00 , oB, oC };
// should get from same bit position
assign iB = iF[1];
assign iC = iF[0];
 
dmux41 sel0 (iS,tA0,tA1,tL0,tL1,oY);
 
endmodule

alu_flag_4b_tb.v

module alu_4b_tb ();
reg[1:0] dS;
reg[3:0] dP,dQ,dF;
wire[3:0] mF,mY;
reg[3:0] cF,cY;
 
integer loop, ecnt;
 
initial begin
  ecnt = 0;
  // TASK: try to put dS assignment in a loop! => shorter code!
  dS = 2'b00; // test add
  for (loop=0;loop<512;loop++) begin
    {dF[0],dP,dQ} = loop;
    #5;
    { cF[0],cY } = dF[0] + dP + dQ;
    if (cY!=mY||cF[0]!==mF[0]) begin
      ecnt = ecnt + 1;
      $display("** Add error (%x+%x+%x=%x@%x|%x:%x)!",dP,dQ,dF[0],mY,cY,
        mF[0],cF[0]);
    end
  end
  dS = 2'b01; // test sub
  for (loop=0;loop<512;loop++) begin
    {dF[1],dP,dQ} = loop;
    #5;
    { cF[1],cY } = dP - dQ - dF[1];
    if (cY!=mY||cF[1]!==mF[1]) begin
      ecnt = ecnt + 1;
      $display("** Sub error (%x-%x-%x=%x@%x)!",dP,dQ,dF[1],mY,cY,
        mF[1],cF[1]);
    end
  end
  dS = 2'b10; // test and
  for (loop=0;loop<256;loop++) begin
    {dP,dQ} = loop;
    #5;
    cY = dP & dQ;
    if (cY!=mY) begin
      ecnt = ecnt + 1;
      $display("** And error (%x&%x=%x@%x)!",dP,dQ,mY,cY);
    end
  end
  dS = 2'b11; // test or
  for (loop=0;loop<256;loop++) begin
    {dP,dQ} = loop;
    #5;
    cY = dP | dQ;
    if (cY!=mY) begin
      ecnt = ecnt + 1;
      $display("** Or error (%x|%x=%x@%x)!",dP,dQ,mY,cY);
    end
  end
  if (ecnt==0) begin
    $display("-- Module alu_4b verified!");
  end
  else begin
    $display("** Module alu_4b with %g error(s)!",ecnt);
  end
end
 
alu_4b dut (dS,dP,dQ,dF,mF,mY);
 
endmodule

This is also shared in Google Doc format (link available in Google Classroom).

nmk206-202425s2_labproject.txt

-----------
LAB PROJECT
-----------
 
You are required to implement a soft-processor core (HDL-based) with the
following minimum requirements:
  - 8-bit microprocessor (instruction size, register size, etc.)
  - 8 general purpose registers
  - 8 ALU functions
  - basic instruction set
    = move data between registers
    = perform basic ALU operations
    = load register with immediate value
 
These requirements are necessary for submission and minimum grade B.
More functionality means better grades:
  - 16-bit/32-bit microprocessor
  - carry circuit for adder (>8b)
  - integer multiply/divide circuit (structural code - NOT behavior)
  - bit-level manipulation (towards microcontroller)
  - instruction fetch unit and memory interface
 
Note#1: Auto-0 for downloaded codes!
 
Note#2: This is a group assignment, but marks will be evaluated individually.
 
Assessment deliverables:
 
1) Verilog source files in a single ZIP file
- make sure only Verilog files are included in the file
- make sure all modules have each a proper testbench
- must be self-checking testbenches
 
2) Technical Document (Specifications)
- not more than 10 pages, no cover page (only list of members' names)
- content:
  = short summary of features
  = block diagram of design
  = list of instructions (description and op-code)
 
3) An online demonstration / Q&A
- not more than 20 minutes
- content:
  = short summary of what has been implemented
  = if completed, demonstrate running the top-level testbench
  = if NOT completed, demonstrate running component-level testbenches
 
PROJECT DUE: Lab Session@W14/14 (Item 1&2). Item 3 TBD.
 
Extra Info:
- each student may email in a contribution percentage information:
  = list all group members (specify project contribution percentage of each)
  = percentage values should total up to 100% (may use fraction e.g. 1/3)
Note: this is optional,but if a member decides to do this, please advise 
the others in group to do the same