ECE243

ECE243 - “SPRING” 2009

Andreas Moshovos (*)

** Warning **

There may be errors or omissions in the notes that follow and of course I’m responsible for them. If you do spot an error please let me know. There no intentional errors in the notes. Irrespective of any typos and other errors, you are responsible for the “correct answer” to questions and problems.

How these relate to the recommended book: In our lectures we will use a slightly different order than the book and also emphasize some topics more than others. Accordingly, there may not always be a direct correspondence between a lecture and a book section. Where possible I will be noting the book sections each lecture corresponds to.

If you want to experiment with NIOS II programs outside of the labs I recommend purchasing a DE-1 board.

Chapter 8 from Altera’s NIOS II Processor Reference: NIOS II Instruction Reference

The complete NIOS II Processor Reference: NIOS II Processor Reference Handbook

These are the notes from 2008. I will be updating as we progress through the course as needed.

THEMATIC SECTION #1: Understanding what computers do at the low level:

What you need to know to successfully program a computer

Week of January 5

1. Introduction, course goals, digital systems and why they are useful.

(book chapter 1 except 1.6 & 1.7)

Week of January 12

2. Using Binary Quantities to Represent Other Things. Typos at the last conversion fixed. Jan 23^rd, 2009.

(book 2.1)

**** Practice questions Answers

* More information about floating point numbers – we will not cover or discuss any of this material.

3. Behavioral Model of Memory.

(book 2.2 – 2.3)

* if there is time we will cover this in the lectures:

- The DE1 SRAM memory chip interface: lecture slides, datasheet

**** Practice questions

4. Introduction to the NIOS II programming model.

(book 3.8 and some of 3.9 and 2.4)

Week of January 19

Please note that in some of the lecture notes I use the io variety of loads and stores. That is a leftover that I have yet to edit from an earlier version of the lab system.

Please replace all ldwio, etc. with the non-io version. IO loads and stores bypass processor caches (we will talk about caches later on). Your program may run slower and in some cases incorrectly if you use the io versions of loads and stores.

5. Using Assembly to Write NIOS II programs.

(book 2.6, 3.10 and the MSL website)

Step-by-Step Examples of loads and stores

6. Simple Control Flow (non straight-line sequencing).

Additions and modifications on January 19, 2010: Simplified code for understanding (removed %hiadj() and %lo() – code is less efficient). Added discussion of if-then, and examples of branch immediate field calculations.

(book 2.4.5, 2.4.6, 3.11.1, 3.11.2)

7. For loops, arrays and do-while loops.

(not as-is in the book related sections 2.11 and 3.15)

Week of January 26

8. Subroutines – Requirements – Calling and Returning

9. Subroutines – Passing Arguments

Examples of functions using strings as arguments

Strings are zero-terminated in C. So “lala” is stored in memory as five bytes: ‘l’, ‘a’, ‘l’, ‘a’, 0.

You can think of strings as arrays of bytes where the last element is always zero.

See lecture 2 for more information.

Week of February 2

10. A Recursive Subroutine