RISC-V
Instruction Set Architecture

General

• History
• Families

Base Variants(base)

• RV32
• RV64
• RV128

Standard Extensions(all)

• A
• B
• C
• D
• E
• F
• G
• I
• J
• L
• M
• N
• P
• Q
• T
• V

Topics

• Foundation
• Non-Standard Extensions
• Addressing Modes
• Registers
• Assembly
• Interrupts
• Microarchitectures

RISC-V has standardized a series of standard extensions beyond the integer base instructions which can be implemented or omitted as desired depending on the design goals (e.g. energy/area/performance/storage goals).

Overview

By default, only the core ISA must be implemented presenting great opportunity for area and energy optimization. However, additional functionality is sometimes desired. RISC-V comes with a series of standard extensions that enable additional functionality beyond the core ISA. Extensions can be implemented and omitted as desired. Those extensions are:

• M - Integer multiplication and division instructions
• A - Atomic instructions
• F - Single-precision floating-point instructions
• D - Double-precision floating-point instructions
• Q - Quad-precision floating-point instructions
• L - Decimal floating point instructions
• C - Compressed instructions
• B - Bit manipulation instructions
• J - Dynamically translated languages
• T - Transactional Memory instructions
• P - Packed-SIMD instructions
• V - Vector operations instructions
• N - User-level interrupt instructions