Status: Tags: #cards/cmpt295/isa Links: Computer Architecture
Instruction Set Architecture (ISA)
Principles
?
- Defines the machine code (instruction set) that a Microprocessor fetches and executes, as well as the memory model
- Contains multiple Instruction Set
Types
Structure
Memory
ISA determines memory qualities like ?
- size of a word
- size and quantity of registers
- total memory size
Word size ?
- how much memory is fetched/written each cycle
- largest size of a variable
Memory size ?
- $2^m x n$
- $2^m$ distinct addressable locations in memory with n bits each
Example
x86 word size ;; 64 bits x86 addressable memory locations ;; 64
x86 bits for each addressible location in memory ;; 8
x86 has x int and y floating point registers ;; 16, 16
Registers
Qualities ?
- Number
- Size
- Data type
- Purpose
Instruction Set
- Format
- Syntax
- Description (semantic)
- Operand model: num, order, and meaning of operands
- memory adressing modes
Conventions
ISA is a formal specification of ?
- how control and data is passed in function calls
- how registers are preserved during function calls
- which registered are callee or caller saved?
Example of x86 formal specifications ?
- Example: x86 has registered reserved for callee saved, return addresses, stack pointers, etc.
References:
Created:: 2022-03-14 03:44