Changes

[[Category:Fall 2022 SPO600]]

This is the schedule and main index page for the [[SPO600]] ''Software Portability and Optimization'' course for Fall 2022.

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|1||Sep 5||[[#Week 1 - Class I|Introduction to the Course / Introduction to the Problem / Computer Architecture Basics]]||[[#Week 1 - Class II|Binary Representation of Data]]||[[#Week 1 Deliverables|Set up for the course / Lab 1]]

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|Reading||Oct 24||style="background: #f0f0ff" colspan="3" align="center"|Reading Week

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|14||Dec 12||[[#Week 14 - Class I|Future Directions in Architecture]]||style="background: #f0f0ff"|(No class)||[[#Week 14 Deliverables|Project Stage 3, December blog posts]]

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*** [[Endian|Endianness]]

** Code that takes advantage of platform-specific features

** Performance

** [[Atomic Operation|Atomic Operations]]

===== Build Process =====

The build process varies significantly between software packages. Most software distribution projects (including Linux distributions such as Ubuntu and Fedora) use a packaging system that further wraps the build process in a standardized script format, so that different software packages can be built using a consistent process.

*** Logically: false or true.

** Binary numbers are resistant to errors, especially when compared to other systems such as analog voltages.

*** If we instead use the same voltages and cable length to carry a binary signal, where 0 volts == off == "0" and 10 volts == on == "1", a signal that had degraded from 10 volts to 9.1 volts would still be counted as a "1" and a 0 volt signal with some stray electromagnetic interference presenting as (say) 0.4 volts would still be counted as "0". However, we will need to use multiple bits to carry larger numbers -- either in parallel (multiple wires side-by-side), or sequentially (multiple bits presented over the same wire in sequence).

* Integers

*** Instead of fixed-length numbers, variable-length numbers are used, with the most common values encoded in the smallest number of bits. This is an effective strategy if the distribution of values in the data set is uneven.

** Repeated sequence encoding (1D, 2D, 3D)

*** Text data can be compressed by building a dictionary of common sequences, which may represent words or complete phrases, where each entry in the dictionary is numbered. The compressed data contains the dictionary plus a sequence of numbers which represent the occurrence of the sequences in the original text. On standard text, this typically enables 10:1 compression.

** Decomposition

** Palletization

*** Images often contain repeated colours, and rarely use all of the available colours in the original encoding scheme. For example, a 1920x1080 "full HD" image contains about 2 million pixels, so if every pixel was a different colour, there would be a maximum of 2 million colours. But it's likely that many of the pixels in the image are the same colour, so there might only be (perhaps) 4000 colours in the image. If each pixel is encoded as a 24-bit value, there are potentially 16 million colours available, and there is no possibility that they are all used. Instead, a palette can be provided which specifies each of the 4000 colours used in the picture, and then each pixel can be encoded as a 12-bit number which selects one of the colours from the palette. The total storage requirement for the original 24-bit scheme is 1920*1080*3 bytes per pixel = 5.9 MB. Using a 12-bit pallette, the storage requirement is 3 * 4096 bytes for the palette plus 1920*1080*1.5 bytes for the image, for a total of 3 MB -- a reduction of almost 50%

# Follow the [[SPO600 Communication Tools]] set-up instructions.

# Optional (strongly recommended): [[SPO600 Host Setup|Set up a personal Linux system]].

# Start work on [[SPO600 Code Review Lab|Lab 1]]. Blog your work.

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*** [[Endian|Endianness]]

** Code that takes advantage of platform-specific features

** Performance

** [[Atomic Operation|Atomic Operations]]

===== Build Process =====

The build process varies significantly between software packages. Most software distribution projects (including Linux distributions such as Ubuntu and Fedora) use a packaging system that further wraps the build process in a standardized script format, so that different software packages can be built using a consistent process.

*** Logically: false or true.

** Binary numbers are resistant to errors, especially when compared to other systems such as analog voltages.

*** If we use instead use the same voltages and cable length to carry a binary signal, where 0 volts == off == "0" and 5 volts == on == "1", a signal that had degraded from 5 volts to 4.1 volts would still be counted as a "1" and a 0 volt signal with some stray electromagnetic interference presenting as (say) 0.4 volts would still be counted as "0". However, we will need to use multiple bits to carry larger numbers -- either in parallel (multiple wires side-by-side), or sequentially (multiple bits presented over the same wire in sequence).

* Integers

* Compression techniques

** Huffman encoding / Adaptive arithmetic encoding

** Repeated sequence encoding (1D, 2D, 3D)

*** Text data can be compressed by building a dictionary of common sequences, which may represent words or complete phrases, where each entry in the dictionary is numbered. The compressed data contains the dictionary plus a sequence of numbers which represent the occurrence of the sequences in the original text. On standard text, this typically enables 10:1 compression.

** Decomposition

** Palletization

*** Images often contain repeated colours, and rarely use all of the available colours in the original encoding scheme. For example, a 1920x1080 "full HD" image contains about 2 million pixels, so if every pixel was a different colour, there would be a maximum of 2 million colours. But it's likely that many of the pixels in the image are the same colour, so there might only be (perhaps) 4000 colours in the image. If each pixel is encoded as a 24-bit value, there are potentially 16 million colours available, and there is no possibility that they are all used. Instead, a palette can be provided which specifies each of the 4000 colours used in the picture, and then each pixel can be encoded as a 12-bit number which selects one of the colours from the palette. The total storage requirement for the original 24-bit scheme is 1920*1080*3 bytes per pixel = 5.9 MB. Using a 12-bit pallette, the storage requirement is 3 * 4096 bytes for the palette plus 1920*1080*1.5 bytes for the image, for a total of 3 MB -- a reduction of almost 50%

{{Admon/tip|Follow the Links!|To get the full benefit of the following material, please follow the links embedded within it. For additional detail, see the Category links at the bottom of those pages -- for example, the [[Category:Computer Architecture|Computer Architecture]] category linked from many of the following pages has over 30 pages of content.}}

* Machine language is not easy to read. [[Assembly Language]] corresponds very closely to machine language, but is (sort of!) human-readable.

* Assembly language is converted into machine code by a particular type of compiler called an [[Assembler]] (sometimes the language itself is also referred to as "Assembler").

==== 6502 ====

* Introduction to the [[6502]] (note the Resources links on that page)

* Introduction to the [[6502 Instructions - Introduction|6502 Instructions]]

* Information about the [[6502 Emulator]] which we will use in this course, and some [[6502_Emulator_Example_Code|example code]]

=== Week 2 - Class II ===

* The image adjustment is performed in the function <code>adjust_channels()</code> in the file <code>adjust_channels.c</code>. There are three implementations:

*# A basic (naive) implementation in C. Although this is a very basic implementation, it is potentially subject to autovectorization.

* The implementation built is dependent on the value of the ADJUST_CHANNEL_IMPLEMENTATION macro.

* '''Please examine, build, and test the code, compare the implementations, and note how it works - there are extensive comments in the code, especially for implementation 2.'''

* Your observations about the code might make a good blog post!

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