Introduction

Machine-Level Programming I:
Introduction
Sept. 10, 2002
Machine-Level Programming I:
Introduction
Sept. 10, 2002
Topics
Topics
nAssembly Programmer’s
Execution Model
nAccessing Information
lRegisters
lMemory
nArithmetic operations
class05.ppt
15-213
“The course that gives CMU its Zip!”

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IA32 Processors
IA32 Processors
Totally Dominate Computer Market
Totally Dominate Computer Market
Evolutionary Design
Evolutionary Design
nStarting in 1978 with 8086
nAdded more features as time goes on
nStill support old features, although obsolete
Complex Instruction Set Computer (CISC)
Complex Instruction Set Computer (CISC)
nMany different instructions with many different formats
lBut, only small subset encountered with Linux programs
nHard to match performance of Reduced Instruction Set
Computers (RISC)
nBut, Intel has done just that!

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X86 Evolution: Programmer’s View
X86 Evolution: Programmer’s View
Name
Name Date Date Transistors Transistors
8086
8086 1978 1978 29K 29K
n16-bit processor. Basis for IBM PC & DOS
nLimited to 1MB address space. DOS only gives you 640K
80286
80286 1982 1982 134K 134K
nAdded elaborate, but not very useful, addressing scheme
nBasis for IBM PC-AT and Windows
386
386 1985 1985 275K 275K
nExtended to 32 bits. Added “flat addressing”
nCapable of running Unix
nLinux/gcc uses no instructions introduced in later models

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X86 Evolution: Programmer’s View
X86 Evolution: Programmer’s View
Name
Name Date Date Transistors Transistors
486
486 1989 1989 1.9M 1.9M
Pentium
Pentium 1993 1993 3.1M 3.1M
Pentium/MMX
Pentium/MMX 1997 1997 4.5M 4.5M
nAdded special collection of instructions for operating on 64-
bit vectors of 1, 2, or 4 byte integer data
PentiumPro
PentiumPro 1995 1995 6.5M 6.5M
nAdded conditional move instructions
nBig change in underlying microarchitecture

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X86 Evolution: Programmer’s View
X86 Evolution: Programmer’s View
Name
Name Date Date Transistors Transistors
Pentium III
Pentium III 1999 1999 8.2M 8.2M
nAdded “streaming SIMD” instructions for operating on 128-bit
vectors of 1, 2, or 4 byte integer or floating point data
nOur fish machines
Pentium 4
Pentium 4 2001 2001 42M 42M
nAdded 8-byte formats and 144 new instructions for streaming
SIMD mode