Transcript Instruction Set Architecture

CS 447: Fall 2001
Chapter 1: Computer
Abstraction and Technology
(Introduction to the course)
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Instruction Set Architecture
• Each “family” of computer
processors are characterized by its
Instruction Set Architecture
– “architecture” for short
– Example architectures:
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Sun UltraSparc
Intel x86
MIPS
IBM mainframe
PowerPC
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Instruction Set Architecture
• Abstraction – a model that renders
lower-level details of computer
systems temporarily invisible in
order to facilitate design of
sophisticated systems
– Allows for design of ISA
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Instruction Set Architecture
• Instruction Set Architecture – an
interface between the hardware and
the software
– Includes:
• Instruction set
– Set of all instructions/operations the computer
is capable of executing
• Instruction encoding/representation
– How the instructions are represented in
memory
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Instruction Set Architecture
• Course objectives:
– Learn the ISA of the MIPS family of
processors
• Learn the set of instructions
• Be able to write programs for this
architecture
• Learn many details about the internal
organization of the MIPS (RISC I/DLX)
architecture
– We want to go from the basics of digital logic
design up through the memory hierarchy and
the software-hardware interface
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Instruction Set Architecture
• Computer instructions include
primitive operations that are
grouped together to form high-level
constructs
– Instruction categories:
arithmetic/logical, constant
manipulation, comparison, load/store,
branch, I/O, data movement
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Instruction Set Architecture
• Instructions have a symbolic (English) and
a binary representation (just like data!)
– Example
• add $1, $2, $3
– Add the contents of registers 2 and 3 and store the
result into register 1
– This representation is called “assembly language”
• 00000000001000100001100000000010
– This representation is called “machine language”.
There’s a 1-to-1 mapping between these two
representations, but this form can be stored in
computer memory
– Programmers can write programs using the
symbolic form of instructions and use an
“assembler” to perform the conversion to the
(we’ll use SPIM for this)
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Instruction Set Architecture
• A processor can only perform
operations on data stored in its
registers
• Registers are memory locations
inside the processor that can only
hold one word of data (typically 32
or 64 bits)
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Instruction Set Architecture
• Typically, programmers don’t have to
worry about ISA
– Compilers translate high-level
programming languages into machinecode instructions and data
• Compilers are more complex than
assemblers, since there’s no 1-to-1 mapping
between high-level programs and machine
instructions
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Processor Design
• Processors are simply collections of
digital-logic circuits
• Digital logic works by performing
Boolean functions (and, or, not)
• The basic boolean functions are
implemented by creating circuits
using transistors (and sometimes
resistors), depending on the
technology process being used
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Processor Fabrication
• Transistors and wires are created on
a microscopic-level on a chip by
applying layers and masks of doped
silicon and aluminum/copper to a
silicon substrate
• The mask pattern is created in a
CAD tool and physically made using
photolithography (photograph)
• The processor ends up being
manufactured on a die.
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Processor Fabrication
• The silicon substrate comes as a
cylinder
• The cylinder is cut into disks
– The disks are called wafers
• The rectangular die is “printed” as
many times as possible on the disk
• The wafer is cut into dies
– Some dies are thrown out right away if
there are observable defects
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Processor Fabrication
• The dies are then wirebonded into a
package
– They can now be tested, more defects
are thrown out
– Yield = # of good dies / # of total dies
made
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