Transcript Sp16 Lect 3 -Chapter 1 of text

ECE 5465
Chapter 1 of text
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Lecture 1 - Introduction
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Outline
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Design abstraction
MU0
Instruction set design
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In the beginning ….
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The dawn of the modern era started with the
stored program computer …..
Much yet to be written
All stored program computers operate on the
same core principals. The start of the
execution of any instructions begins :
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Mem(PC)  IR
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Modern design
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All modern designs are done using design
abstraction.
The abstraction level description ends up as
transistors on an ic after translation by multiple
CAD tools.
There are various dimension to abstraction.
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The hardware dimension
The HDL dimension
The power dimension
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MU0
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MU0 is much like MicroBaby, an
accumulator architecture
MU0 instruction set is simpler than the
MicroBaby instruction set. It only has Load,
Store, Add, and Subtract, and two conditional
jumps.
It has 16-bit data and address versus just the
8-bit of MicroBaby, so it has 64K bytes of
main memory.
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MU0 Structure
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The datapath and instructions
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MU0 datapath detail
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A more detailed
view of the
architecture
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The MU0 instruction bits
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Instruction encoding – ref text
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Instruction set design
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Instruction set design involves choosing the
binary encoding of each instruction
Best to choose one where the instruction word
is broken into fields, with each field having a
specific meaning or purpose.
Then, what goes into what happens on the
busses during each cycle of execution.
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Here we can further study MicroBaby and the
timing of all the control signals.
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Then RISC was discussed
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The reference for the paper that started it all is given. (for RISC on
page 24) “The Case for the Reduced Instruction Set Computer”
Core elements of “pure” RISC (see pg 24)
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RISC advantages
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Small die size / shorter development time / higher performance
RISC drawbacks
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Fixed instruction size
Load/Store
Large Register Bank
Poor code density
No x86 compatibility – no IBM PC compatibility
ARMs answer for code density – the THUMB architecture
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