CPE 431531 Chapter 2 Instructions: Language of the Computer

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CPE 431/531Chapter 2 Instructions Language
of the Computer

• Dr. Rhonda Kay Gaede
• UAH

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2.1 Introduction

• The words of a computers language are called
  instructions and its vocabulary is called an
  instruction set.
• Instruction sets are more similar than they are
  different
• Goal is to find a language that makes it easy to
  build the hardware
• Stored-program concept
• Instructions and data can be stored in memory in
  as numbers

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2.2 Operations of the Computer Hardware Basics
of MIPS Arithmetic

• We need arithmetic
• add a, b, c
• From high level
• a b c d e
• Fixing the number of operands keeps the hardware
  simple.
• Design Principle 1
• Simplicity favors regularity

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2.2 Operations of the Computer Hardware The
Role of the Compiler

• Compilation is the process of creating MIPS
  assembly language instructions from a high level
  language instruction (C).
• Examples
• a b c
• d a e
• f (g h) (i j)

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2.3 Operands of the Computer Hardware MIPS
Basics

• In high level languages, variables live in
  _____________.
• In MIPS assembly, operands live only in
  _______________.
• ______________________ instructions move
  variables from memory/registers to
  registers/memory.
• MIPS has 32 registers and an address space of 232
  memory bytes.
• Design Principle 2 Smaller is faster.
• _____________________________________

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2.3 Operands of the Computer Hardware Memory
Operands First Pass

• Data transfer instructions
• _____________________________________________
• _____________________________________________
• Compiling an Assignment When an Operand is in
  Memory
• A is an array of 100 words, base pointer s3
• g s1, h s2
• g h A8
• Hardware/Software Interface
• A compiler _______________, ______________________
  ______, _____________________________________.

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2.3 Operands of the Computer Hardware - Memory
Operands Second Pass

• Bytes/Words
• 32-bit words consist of 4 8-bit bytes
• MIPS is _________ addressable
• g h A8
  A12 h A8
• Constants or Immediate Operands
• addi s3, s3,4
• Design Principle 3
• ________________________________________

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2.4 Representing Instructions in the Computer
R-type Instructions

• Translating a MIPS assembly instruction into a
  machine instruction _________________________
• MIPS Fields
• op rd
• rs shamt
• rt funct

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2.4 Representing Instructions in the Computer
I-Type Instructions

• Design Principle 4
• ___________________________________
• For data transfer, address offset is limited to
  _________ bytes, _________ words.
• Another Translation Example A300 h A300

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2.6 Instructions for Making Decisions
Instruction Examples and Compilation

• Two conditional ones for now
• beq register1, register2, L1
• bne register1, register2, L1
• if (i j)
• f g h
• else
• f g h

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2.6 Instructions for Making Decisions Add
Another Decision

• Less than is useful, i.e., for (i 0 i lt 10
  i)
• slti t0, s1, 10
• bne t0, zero, offset
• slt t0, s0, s1
• bne t0, zero, offset

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2.7 Supporting Procedures in Computer Hardware
Getting Started

• Steps involved in calling a procedure (function)
• Make parameters available to the called
  procedure.
• Transfer control to the procedure
• Acquire the needed space for the procedure.
• Perform the desired task.
• Make result available to the calling procedure
• Transfer control back to calling procedure.
• Support comes in registers and instructions
• Registers
• a0-a3 - _______________________________________
• v0-v1 - _______________________________________
• ra ______________________________________
• Instructions
• jal
• jr

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2.7 Supporting Procedures in Computer Hardware
Compiling a Leaf Procedure

• int leaf_example (int g, int h, int i, int j)
• int f
• f (g h) - (i j)
• return(f)
• leaf_example sub sp, sp, 12
• sw t1, 8(sp)
• sw t0, 4(sp)
• sw s0, 0(sp)
• add t0, a0, a1
• add t1, a2, a3
• sub s0, t0, t1
• add v0, s0, Zero
• lw s0, 0(sp)
• lw t0, 4(sp)
• lw t1, 8(sp)
• add sp, sp, 12

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2.7 Supporting Procedures in Computer Hardware
Leaf Example Stack
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2.7 Supporting Procedures in Computer Hardware
Nested Procedures

• Calling Procedure
• Pushes its argument registers onto the stack
  ___________ ____________________
• Pushes any temporary registers it needs
  _____________________ ____________________________
  _
• Pushes ra onto the stack
• Called Procedure
• Pushes saved registers onto the stack

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2.7 Supporting Procedures in Computer Hardware
Nested Procedure Compilation
int fact (int n) if (n lt 1) return (1) else
return (fact(n-1)) fact addi sp, sp,
-8 sw ra, 4(sp) sw a0, 0(sp) slti t0,
a0, 1 beq t0, zero, L1 addi v0, zero,
1 addi sp, sp, 8 jr ra L1 addi a0, a0,
-1 jal fact lw a0, 0(sp) lw ra,
4(sp) addi sp, sp, 8 mul v0, a0,
v0 jr ra
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2.7 Supporting Procedures in Computer Hardware
More About the Stack

• Allocating Space for Automatic Variables
• In addition to storing saved registers, the stack
  holds ___________________________________
• Saved registers ______________________________
  ________________________________

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2.7 Supporting Procedures in Computer Hardware
The Heap

• Space is needed for static variables and dynamic
  data structures
• Space is reserved and freed on the heap using
  explicit system calls.
• Register Usage
• zero 0
• v0-v1 2-3
• a0-a3 4-7
• t0-t7 8-15
• s0-s7 16-23
• t8-t9 24-25
• gp 28
• sp 29
• fp 30
• ra 31

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2.9 MIPS Addressing for 32-Bit Immediates and
Addresses 32-Bit Immediates

• 32-Bit Immediate Operands
• Upper 16 Bits - _____________________________
• Lower 16 Bits - _____________________________
• Loading 003D 0900

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2.9 MIPS Addressing for 32-Bit Immediates and
Addresses Addresses

• Addresses in Branches and Jumps
• j 10000
• bne s0, s1, Exit
• Elaboration For jumps, we give only 28 bits,
  from whence springeth the other 4?
• Branching Far Away

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2.9 MIPS Addressing Addressing Mode Summary

• MIPS Addressing Mode Summary
• Register
• Base
• Immediate
• PC-Relative
• Pseudodirect

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2.10 Translating and Starting a Program
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2.11 How Compilers Optimize

• High-level Optimizations
• _______________________
• _______________________
• Local and Global Optimizations
• ________________________
• _________________________
• _________________________

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2.16 Real Stuff IA-32 Instructions The Early
Years

• 1978 - 8086 ____________________________________
• 1980 8087 ____________________________________
  _______________________________________
• 1982 80286 ____________________________________
• 1985 80386 ____________________________________
  _________________________________
• 1989-1995
• 1989 80486, 1992 Pentium, 1995 Pentium Pro
• _______________________________________________
• 1997 MMX _________________________________
  ____________________________________________

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2.16 Real Stuff IA-32 Instructions The Later
Years

• 1999 Pentium III _______________________________
  _______________________________________________
  ________________________________________
• 2001 Pentium 4 ________________________________
  _______________________________________
• 2003 AMD ____________________________________
  __________________________
• 2004 EM64T __________________________________
  _______________________________________________
• This checkered ancestry has led to an
  architecture that is difficult to explain and
  impossible to love. What it lacks in ___________,
  it makes up in ____________.

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2.17 Fallacies and Pitfalls

• Fallacy More powerful instructions mean higher
  performance.
• Fallacy Write in assembly language to obtain the
  highest performance.
• Pitfall Forgetting that sequential word
  addresses in machines with byte addressing do not
  differ by one.