This document discusses processor organization and design. It introduces the topic and explains that it will cover choosing general characteristics of a processor like memory model, data and instruction bit width, and register file implementation. It will not cover detailed impacts of these choices or the physical realization of a processor. The document then provides background on what a processor is, common instruction set architectures, and von Neumann and Harvard computer architectures before exploring the main design decisions around memory model, data widths, instruction widths, and register files.

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Processor Organization
Dominik Salvet
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Processor Organization
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Introduction
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What are we going to talk about?
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Brief explanation of a processor and a computer
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A little bit of the first phase of a processor designing
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Choosing general characteristics of a processor
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What are we not going to talk about?
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Detail impacts of the processor characteristics
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Designing Instruction Set Architecture (ISA)
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Physical realization of a processor
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Virtual realization of a processor

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Processor
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Also referred as Central Processing Unit (CPU)
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A sophisticated machine to process data
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Executes it's native instructions over data
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Instructions are bit vectors just like data
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Popular Instruction Set Architecture types
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RISC (Reduced Instruction Set Computer)
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CISC (Complex Instruction Set Computer)
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Consists at least of
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ALU (Arithmetic Logic Unit)
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CU (Control Unit)

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Computer
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A CPU and some kind of memory
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Input/Output (I/O) devices can be considered as
read-only/write-only memory
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It is based on a theoretical architecture model
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Von Neumann architecture
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Harvard architecture

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Decisions Before Us
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Memory model
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Data bit width
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Instruction bit width
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Register file implementation

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Memory Model
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Communication with Input/Output devices
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Von Neumann vs Harvard architecture
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Address bit width
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Smallest addressable memory unit

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Data Bit Width
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Native processor bit width to work with data
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Defines bit width of most internal registers
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Instructions over data with this bit width can
be executed without additional overhead
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Multiple data bit widths can also be supported

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Instruction Bit Width
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Fixed length
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Bigger programs and lower overhead with processing
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Variable length
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Smaller programs and higher overhead with processing
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Number of individual instructions available
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Instruction may hold it's constant data within itself

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Register File Implementation
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Less registers
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Almost always faster access
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Possible to have shorter instruction bit width
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More registers
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Possible to keep more program context in registers
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Bit width of the registers is often derived from
data bit width
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Other registers

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Processor Organization
Questions?
Dominik Salvet
github.com/dominiksalvet