OVM 101.

Test Environment Structure

diagram

// Top level "module" contains class based test environment
//        and structural interface that drives DUT (module)
module top;

import ovm_pkg::*;
import my_pkg::*;

...
dut_if dut_if_inst0 ();
dut dut_inst0 (._if (dut_if_inst0) );

initial
begin
    run_test ("my_test_set");
end

endmodule : top

// ovm classes
// usually classes of test environment that includes fixed test bench
// and variable test sets

`include "ovm_macros.svh"

package my_package;
import ovm_pkg::*;

// Fixed test environment
class my_test_env extends ovm_env;
    `ovm_component_utils (my_test_env)

    // constructor
    function new (string s, ovm_component inst_parent);
        super.new (s, inst_parent);
    endfunction : new

    function void build;
        super.build ();
    endfunction : build

    task run;
        #10 ovm_top.stop_request();
    endtask : run

endclass : my_test_env

class my_test_set extends ovm_test;
    `ovm_component_utils (my_test_set)

    my_test_env my_test_env_handle;

    // constructor
    function new(string s, ovm_component inst_parent); 
        super.new(s, inst_parent);
    endfunction : new

    function void build;
        super.build();
        my_test_env_handle = my_test_env::type_id::create 
            ("my_test_env_handle", this);
    endfunction : build

endclass : my_test_set

// interface dut_if(); -> between test components and DUT
interface dut_if ();
...
endinterface : dut_if

// Design under test
module DUT (dut_if _if); 
endmodule : dut

UVM/OVM primer.

Basic Concepts:

• Constrained random, coverage-driven verification
• Configurable, flexible, test benches
• Verification IP reuse

• Separation of tests from test bench
• TLM communication
• Layered sequential stimulus
• Standardized messaging
• Register layer (UVM)

UVM Class Hierarchy

• uvm_object

OVM Class Hierarchy

• ovm_object
• obm_report_object
• ovm_component
• ovm_env
• ovm_test
• ovm_agent
• ovm_sequencer
• ovm_driver
• ovm_monitor
• ovm_scoreboard
• ovm_agent usually contains driver / monitor and sequencer

Prerequisite:

• Verification Planning
• Constrained Random Verification
• SystemVerilog
• UVM/OVM Class Library, OOP, TLM

Useful Links:

• First Program
• Connecting Env to DUT
• Connecting Components
• Transactions
• Sequences and Tests
• Mnitors and Subscribers
• Reporting
• UVM tutorial
• OVM tutorial
• OVM Class Reference Online
• OVM Class Reference PDF

Java Math.

Math

• Math.round()

BigDecimal

   java.math.BigDecimal

• BigDecimal (int)
• BigDecimal (double)
• BigDecimal (long)
• BigDecimal (String) // better

• Methods
• add (value)
• compareTo(value)
• divide(value, scale, rounding-mode)
• multiply(value)
• setScale(scale, rounding-mode)
• subtract(value)
• toString()

   java.math.RoundingMode

• HALF_UP
• HALF_EVEN

import java.math.*; // imports all classes and 
                    // enumerations in java.math

// convert subtotal and discount percent to 
BigDecimal BigDecimal decimalSubtotal =
    new BigDecimal(Double.toString(subtotal)); 
decimalSubtotal =
    decimalSubtotal.setScale(2, RoundingMode.HALF_UP); 
BigDecimal decimalDiscountPercent =
    new BigDecimal(Double.toString(discountPercent));

// calculate discount amount 
BigDecimal discountAmount =
    decimalSubtotal.multiply(decimalDiscountPercent); 
discountAmount = discountAmount.setScale(
    2, RoundingMode.HALF_UP);
// calculate total before tax, sales tax, and total
BigDecimal totalBeforeTax =
   decimalSubtotal.subtract(discountAmount);
BigDecimal salesTaxPercent =
   new BigDecimal(SALES_TAX_PCT);
BigDecimal salesTax =
   salesTaxPercent.multiply(totalBeforeTax);
salesTax = salesTax.setScale(2, RoundingMode.HALF_UP);
BigDecimal total = totalBeforeTax.add(salesTax);

// Create another BigDecimal object from existing BigDecimal Object
BigDecimal total2 = new BigDecimal(total.toString());

Java OOP.

• Java String is immutable object

Using "this"

public class MyClass {
     private final String value;
     private final String type;

     public MyClass(int x){
         this(Integer.toString(x), "int");
     }

     public MyClass(boolean x){
         this(Boolean.toString(x), "boolean");
     }

     public String toString(){
         return value;
     }

     public String getType(){
         return type;
     }

     private MyClass(String value, String type){
         this.value = value;
         this.type = type;
     }
}

Java Exceptions.

Exception Basics

Order of Catch Matters

userChoice = 0; //initialize it
    try {
        userChoice = getInput(inputReader); 
    }// order of catch is important

    catch (NullPointerException e) { 
        System.out.println("Message:"+e.getMessage());
    }
    catch (MyOutOfRangeException e) {
        System.out.println("Message: " + e.getMessage()); 
    }
    catch (Exception e) {
        System.out.println("Catch all Exception"); 
    }

    finally { //always exectued with our without catch
        if (userChoice==0) //still has initial value
            System.out.println("Please try again ..."); 
        else
            System.out.println("Your choice is:"+ userChoice); 
    }
 

Prevent Exceptions As Possible

// Get valid numeric format
public static double getDouble(Scanner sc, String prompt) {
          double d = 0.0;
          boolean isValid = false;
          while (isValid == false)
          {
              System.out.print(prompt);
              if (sc.hasNextDouble())
              {
                  d = sc.nextDouble();
                  isValid = true;
              }
              else {
                  System.out.println(
                      "Error! Invalid number. Try again.");
              }
              sc.nextLine(); // discard any other data
           }
           return d; 
}

// Get valid numeric format
public static double getDoubleWithin (
        Scanner sc,
        String prompt,
        double min, double max )
{
    double d = 0.0;
    boolean isValid = false;
    while (isValid == false) {
        d = getDouble(sc, prompt);
        if (d <= min) {
            System.out.println(
                "Error! Number must be greater than " + 
                min + ".");
        }
        else if (d >= max){
            System.out.println(
                "Error! Number must be less than " +
                max + ".");
        } 
        else
            isValid = true;
    }
    return d; 
}

Scanner sc = new Scanner(System.in);
double subtotal1 = getDouble(sc, "Enter subtotal: "); 
double subtotal2 = getDoubleWithinRange(
                              sc,
                             "Enter subtotal: ",
                             0,
                             10000);

From Git to GitHub.

Create Folders in GitHub

1. When upload files, pull the whole directory to the area.
2. Add "dir/" in front of files to be committed.
3. Use "git add folder/filename" or "git add file_path" and then "git commit" and "git push"
4. In GitHub, click "Create new files", in the file name box, add "path_name / file_name"

Clone GitHub Repository

# git clone github_url local_directory
1. git clone https://github.com/changanna/java.git local_java_dir
2. git clong git@github.com:changanna/java.git # SSH protocol
3. git add file_path
4. git add .
5. git commit
6. git push

Check in Folders/Files For First Time

1.git init
2.git config user.name "someone"
3.git config user.email "someone@someplace.com"
4.git add *
5.git commit -m "some init msg"
6.git push

Check in Folders/Files Settings

1. using sourcetree: 
   Repository -> Repository Settings --> Advanced --> uncheck "Use global user settings" box

2. Repository > Repository Settings > Edit config file.
   Check if the [user] section exists. If the user section is missing, add it.

   [user]
   name = "your name"
   email = "your email"

3. Don't use "git pull" to skip settings
   % git fetch
   % git reset --hard origin/master
   % git fetch && git reset --hard HEAD

Git Quick Guides

Git 101.

Basics:

• help / man 
• man git
• man git-log / man git-commit
• git help log

• git config --global user.name <your_name>
• git config --global user.email you@yourdomain.com
• git config --get remote.origin.ur /home/amy/project
• git config -l # 
• git init
• git status
• git log (more)
• git add <filename> (more)
• git commit -m "message" <filename> (more)
• git branch <branch_name> (more)
• git checkout master 
• git checkout -b <branch_name>
• git branch (check branch is created)
• git merge (more)
• git branch -d <branch-to-delete> # but git ensure the changes is in current branch
• git branch -D <branch-to-remove> # no changes are reserved
• git branch -r origin/master # keeps a pristine copy of original branch
• git revert (more)
• git clone <directory> <new cloned directory>
• git commit -a # to commit the new cloned directory in repository
• ex: git clone amy.org:/home/amy/project  my_repo_directory # ssh protocol
• git pull <new cloned directory>
• git fetch <new cloned directory> # to inspect new changes and decide whether to merge
• git log -p HEAD..FETCH_HEAD
• gitk HEAD..FETCH_HEAD
• gitk HEAD...FETCH_HEAD  # show everything reachable from either one but not both
• git remote add <new directory> <from directory>
• git fetch <new directory> # inspect without merging
• git log -p master..new_directory/master # show a list of changes
• git merge new_directory/master
• git pull . remotes/new_directory/master # same as above commands, merge without checking
• git pull # update all changes to local files
• git push # update files in remote github repository

• git show <commit number>
• git show HEAD # tip of current branch
• git show HEAD^    # parent
• git show HEAD^^  # grandparent
• git show experiment1 # tip of experiment1 branch

• more...
• git rm [-n][-q][-r] <dir to be removed>
• git tag v2.5 <your own commit name.
• git diff v2.5 HEAD
• git branch new_branch v2.5
• git reset --hard HEAD^
• git grep "key_word" v2.5
• git log v2.5..v2.7
• git log --since="2 days ago"
• git log v2.5..  Makefile
• git log master .. child # commit in child but not master
• gitk --since="2 days ago"  codec/
• git diff  v2.5:Makefile  HEAD:Makefile.in
• git show v2.5:Makefile
• git docs
• git tutorial files

EXAMPLE

% tar xzf project.tar.gz
% cd project
% git init
% git add .
% git commit
% git add file1 file2
% git diff --cached
% git status
% git commit -a -m "new changes"
% git log -p
% git log --stat --summary
% git branch experiment1
% git branch
% git checkout experiment1
    ... (edit files)
% git commit -a
% git checkout master
    ... (edit files)
% git commit -a
% git merge experiment1
% git diff
% git commit -a
% (git push to update files in remote github repository)
% git branch -d experiment1
% git branch -D crazy-idea-to-remove

GitHub:

• git remote add origin https://github.com/myaccount/mynewrepository.git
• git push -u origin master_branch_name
• git hash object - use hash code as an identifier for a specific commit
• git revert <has code number> - to backtrack
• git pull origin master_branch_name - get most recent changes to local computer