3. MIPS Instruction Set1

생성일: 2021년 9월 12일 오후 6:31

Instruction Set (명령집합)

• The vocabulary of commands understood by a given architecture
• The words of a computer's language are called instructions, and its vocabulary is called instruction set

Machine Language

1. Programming languages
   1. High level programming languages
      • C, C++, Java, Python....
2. Assembly programming languages
   1. symbolic machine languages
3. Machine languages
   1. Binary(1과0), IA32, IA64, ARM, MIPS, Power PC

Translator

• Compiler : high-level language ⇒ machine language
• Assembler : assembly language ⇒ machine language (A part of compiler)
• Interpreter : Translate and execute programs directly
  • JVM(Java virtual machine)

Compiler

Source Program : high-level 언어로 작성된 프로그램
Target Program : machine 언어(x86, MIPS, ARM)로 작성된 프로그램

• 좋은 Compiler는?
  • Generate correct code
  • Target code runs fast
  • Compiler runs fast
  • Support for separate compilation, good diagnostics for errors
• Compilation Process

preprocessor = 전처리기

• Compiler Phases

Machine State

• ISA defines machine states and instructions
• Registers(Register Files)
  • CPU internal storage to store data fetched from memory
    • Can be read or written in a single cycle
    • Arithmetic and logic operations are usually performed on registers
    • MIPS ISA has 32 32-bit registers: Each register consists of 32 flip-flops
  • Top level of the memory hierarchy
    • Registers ↔ Caches ↔ Memory ↔ Hard disk
    • Registers are visible to programmers and maintained by programmers
    • Caches are invisible to programmers and maintained by HW
• Smaller is Faster
  • 32 registers의 제한 이유 : A very large number of registers may increase the clock cycle time simply because it takes electronic signals longer when they must travel farther

Memory

• A large, single dimensional array, starting at address 0
• Store programs (which contains both instructions and data)
• To transfer data, use load (memory to register) and store (register to memory) instructions

Memory Operands (피연산자)

• load = The data transfer instruction that copies data from memory to a register
• The format of the load instruction is the name of the operation followed by the register to be loaded, then a constant and register used to access memory
• memory address = constant portion of the instruction + contents of the second register forms

Data Size

• word: the default data size for computation
  • 32b for 32b ISA, 64b for 64b ISA
• Double word: 64b data
• Half word: 16b data
• Byte: 8b data

Machine Instruction

• Opcode(연산코드) : Specifies the operation to be performed
  • ADD, MULT, LOAD, STORE, JUMP
• Operands : Specifies the location of data
  • Source operands (input data)
  • Destination operands (output data)
  • The location can be
    • Memory operand specified by a memory address : Ex) 8(R2), x1004F
    • Register operand specified by a register number : R1

MIPS Instruction Types

• Arithmetic and logic instructions
  • ADD, MULT, XOR, SHIFT...
• Data transfer instructions (memory instructions)
  • LOAD, STORE
• Control transfer instructions (branch instructions)
  • Change the program control flow
  • JUMP, CALL, RETURN, BEQ

MIPS Instruction Format - R type

32 bits long

MIPS Instruction Format - I type

32 bits long

MIPS Instruction Format - J type

32 bits long

• Jump(j), Jump and link(jal) instructions have two fields
  • Opcode (6 bits)
  • Address (26 bits)

MIPS Addressing Modes

• Register addressing
  • Address is in a register
  • jr $ra (indirect branches)
• Base addressing
  • Address is the sum of register(base register) and a constant(offset)
  • Idw $s0, 100($s1)
• Immediate addressing
  • For constant operands (immediate operand)
  • add $t1, $t2, 3
• PC-relative addressing
  • Address is the sum of PC and constant(offset)
  • beq $s0, $s1, L1
• Pseudodirect addressing
  • Address is the 26 bit offset concatenated with the upper bits of PC
  • j L 1

MIPS Instruction Example