Supported Instructions

Supported Instructions

• Supported Instructions refer to the specific operations that the CPU can perform.

  • Arithmetic Operations: This includes operations like addition and subtraction.

  • Data Movement: This involves loading and storing data between various memory locations.

  • Control Flow: Branching and jumping within the execution flow of programs.

Data Types

• The types of data that the processor can handle:

  • Integers: Whole numbers without fractional parts.

  • Floating-Point Numbers: Numbers that can represent a fractional component.

  • Characters: Individual symbols or letters.

Registers

• Registers serve as small, fast storage locations within the CPU for temporary data during processing.

Memory Management

• Memory management is pivotal in how hardware manages main memory.

  • Key features include virtual memory, allowing systems to use disk storage as an extension of RAM.

Input/Output Model

• Pertains to the methods used by the processor for interacting with peripheral devices.

Example of an Instruction Set Architecture (ISA)

• x86 Architecture: A widely used example of ISA in PCs, designed as a Complex Instruction Set Computer (CISC).

  • Arithmetic Operations: Instructions include ADD for addition and SUB for subtraction.

  • Data Movement: Instructions like MOV to transfer data between registers and memory.

  • Control Flow: Instructions such as JMP for unconditional jumps.

Examples of CISC Architectures

1. x86 Architecture

   • Utilized by Intel and AMD processors with a rich instruction set allowing complex operations.

   • Instructions include MOV, ADD, SUB, JMP, and CALL.

2. Motorola 68k Family

   • Features multiple operations executed in a single instruction.

3. VAX Architecture

   • Complex instruction set by Digital Equipment Corporation.

Examples of RISC Architectures

1. ARM Architecture

   • Noted for its efficient instruction set, popular in mobile and embedded systems.

2. MIPS Architecture

   • Designed for efficient pipelining, with a simple instruction set.

3. Power Architecture

   • Emphasizes simplicity for high performance across various applications.

Operand Storage in the CPU

• Operand storage in the CPU refers to temporary storage methods for data during program execution.

  • Registers: High-speed storage locations holding operands and intermediate results.

    • General-Purpose Registers: Store frequently accessed data.

    • Special-Purpose Registers: Store values like the program counter and stack pointer.

Cache Memory

• L1 Cache: Fastest cache located within the CPU core for frequently used data.

• L2 and L3 Cache: Larger caches providing faster access than main memory but slower than L1.

Main Memory (RAM)

• Stores program instructions and data manipulated by the CPU.

Stack Memory

• A region of memory for temporary data, including function call details and local variables.

  • Stack Pointer: Manages memory allocation and deallocation.

Virtual Memory

• A memory management technique utilizing disk storage as an extension of RAM.

  • Page Tables: Translate virtual addresses to physical addresses.

Explicit Named Operands

• The number of explicitly named operands in a computer instruction relates to how many data items are referenced.

  • For instance, the instruction MOV eax, 123 uses two explicit named operands: eax (the register) and 123 (an immediate value).

Operand Locations

Common Operand Locations

1. Registers: Locations within CPU for fast access.

   • E.g., ADD R1, R2 uses operands from registers.

2. Immediate Values: Fixed values specified in the instruction.

   • E.g., MOV R1, #10 uses an immediate operand.

3. Memory: Operands located at specified memory locations.

   • E.g., LOAD R1, [address] fetches from memory.

4. Stack: Temporary values for function calls.

   • E.g., PUSH R1 places value onto the stack.

5. Accumulator: Operands in a special register used for arithmetic.

   • E.g., ADD A, B operates using an accumulator register.

6. Indexed: Addressing operands with an index/offset.

   • E.g., LOAD R1, [base + offset] accesses indexed memory.

7. Condition Codes: Flags affecting instruction execution.

   • E.g., BRANCH IF ZERO uses condition codes.

Instruction Set Architectures (ISAs)

• ISAs define the operations a processor can execute.

Types of Operations in ISAs

1. Arithmetic Operations: Add, subtract, multiply, divide, increment, decrement.

2. Logical Operations: AND, OR, XOR, NOT.

3. Data Movement Operations: MOVE, LOAD, STORE.

4. Control Flow Operations: JMP, CALL, RET.

5. Shift and Rotate Operations: Shift left/right, rotate left/right.

6. Comparison Operations: Compare, set conditions.

7. Control Operations: Halt, no operation.

Operand Types and Sizes

Common Operand Types

1. **Integer Operands

• Sizes: 8-bit, 16-bit, 32-bit, 64-bit.

2. Floating-Point Operands

• Sizes: 32-bit, 64-bit.

3. Character/String Operands

• Typically 8 bits per character.

4. Pointer Operands

• Size matches the native word size.

5. Boolean Operands

• Typically stored as 1-bit values.

How Operands Are Specified

1. Registers: Specified by name (e.g., R1).

2. Memory Addresses: Specified directly (e.g., [0x1234]).

3. Immediate Values: Specified within instruction (e.g., MOV R1, #10).

4. Indirect Addressing: Using addresses in registers (e.g., [R2]).

5. Indexed Addressing: Using base and offset (e.g., [R3 + 4]).

6. Stack Pointers: Relative to stack pointer (e.g., [SP]).

Types of Instruction Set Architectures (ISAs)

1. Stack Architecture

• Operands are on the stack; pop and push operations are common.

2. Accumulator Architecture

• One operand is the accumulator used for arithmetic/logical operations.

3. General Purpose Register (GPR) Architecture

• All operands are explicitly mentioned, allowing flexibility in modern processing.

Trade-offs of Different ISAs

• Each ISA type has unique advantages and impacts processing and application design.