ARM Full Form and RISC-V Full Form
ARM Full Form:
Advanced RISC Machine
RISC-V Full Form:
Reduced Instruction Set Computer – Five
(V represents the Roman numeral for 5)
Both architectures follow RISC principles, focusing on simple instructions, faster execution, and better power efficiency.
ARM Architecture Explained (Conceptual Overview)
A typical ARM processor architecture consists of:
- Processor Core
- Register File
- ALU (Arithmetic Logic Unit)
- Pipelined Execution Stages
- Cache Memory (L1, L2)
- Bus Interface
- Interrupt Controller
- Memory Management Unit (MMU)
ARM uses a deep pipelined architecture, allowing multiple instructions to be processed simultaneously.
This results in:
- High performance
- Excellent power efficiency
- Proven reliability
ARM processors are widely used in:
- Smartphones
- Automotive ECUs
- Industrial controllers
- Embedded and IoT devices
RISC-V Architecture Explained
1. Instruction Set Architecture (ISA)
RISC-V uses a modular and extensible ISA:
- RV32I – 32-bit base ISA
- RV64I – 64-bit base ISA
- RV128I – Future high-end systems
Designers implement only what they need, reducing hardware complexity.
2. Register File
- 32 general-purpose registers
- 32-bit or 64-bit depending on implementation
- Simple decoding and efficient execution
3. Modular Extensions
| Extension | Purpose |
|---|
| M | Multiply & Divide |
| A | Atomic operations |
| F | Floating-point |
| D | Double-precision floating point |
| C | Compressed instructions |
| V | Vector processing |
This modularity makes RISC-V highly customizable.
4. Pipeline and Execution
Standard pipeline stages:
- Fetch
- Decode
- Execute
- Memory
- Write-back
The simplicity of the ISA allows efficient pipelining and scaling.
5. Privilege Levels
| Mode | Purpose |
|---|
| User (U) | Applications |
| Supervisor (S) | Operating System |
| Machine (M) | Firmware & bootloader |
RISC-V scales from microcontrollers to full Linux-based systems.
RISC-V vs ARM: Performance Comparison
ARM Performance
- Highly optimized commercial cores
- Proven in smartphones and automotive systems
- Excellent compiler and OS support
- Stable real-world performance
RISC-V Performance
- Performance depends on implementation
- Many cores match ARM Cortex-M and Cortex-A
- Rapid progress in AI, ML, and HPC domains
Verdict:
ARM leads today in production-grade performance, while RISC-V is closing the gap quickly.
RISC-V vs ARM: Power Efficiency & Power Consumption
ARM Power Efficiency
- Ultra-low power designs
- Advanced power management
- Ideal for battery-powered mass-market devices
RISC-V Power Efficiency
- Minimal ISA overhead
- Excellent for custom low-power designs
- Power efficiency depends on core design
Verdict:
ARM excels in mass-market low-power products, while RISC-V offers design-level power optimization.
Benefits of ARM
- Industry-proven architecture
- Mature toolchains and RTOS support
- Large global job market
- Excellent power efficiency
- Strong presence in automotive and IoT
Benefits of RISC-V
- Open-source ISA
- No licensing or royalty fees
- Fully customizable architecture
- No vendor lock-in
- Ideal for startups and chip designers
- Future-ready processor ecosystem
Which Companies Use ARM Processors?
ARM processors are used by:
- Apple
- Qualcomm
- Samsung
- NVIDIA
- NXP
- STMicroelectronics
- Texas Instruments
- Broadcom
ARM dominates mobile, automotive, and embedded markets today.
Which Companies Use RISC-V?
RISC-V is adopted by:
- Google
- NVIDIA
- Intel
- Qualcomm
- Western Digital
- Bosch
- Alibaba
- SiFive
Used in AI accelerators, controllers, automotive systems, and IoT devices.
Why Companies Are Moving from ARM to RISC-V
Companies explore RISC-V because:
- Zero royalty cost
- Full design control
- No vendor lock-in
- Faster innovation cycles
- Government and academic support
Note: Most companies currently use RISC-V alongside ARM, not as a complete replacement.
RISC-V vs ARM: Comparison Table
| Feature | ARM | RISC-V |
|---|
| Architecture Type | RISC | RISC |
| Instruction Set | Proprietary | Open-source |
| Licensing Model | Paid license & royalties | Free, no royalties |
| Customization | Limited | Fully customizable |
| Vendor Lock-in | Yes | No |
| Ecosystem Maturity | Very mature | Rapidly growing |
| Performance | Production-proven | Implementation-dependent |
| Power Efficiency | Best for mass-market devices | Best for custom designs |
| Toolchain & OS Support | Strong & stable | Improving rapidly |
| Industry Usage | Smartphones, automotive, IoT | AI, controllers, custom silicon |
Final Verdict: RISC-V vs ARM – Which Is Better?
There is no single winner.
- ARM is best for current embedded jobs and commercial products
- RISC-V is ideal for future semiconductor and processor design careers
Best Learning Strategy for Embedded Students
Learn ARM first → Add RISC-V → Become future-ready.
