# Instruction sets: Arm, RISC-V, x86 and others

The instruction set is the language a processor understands. Who owns it, and who can build chips with it, shapes everything around it.

Page: https://dharanova.com/learn/isa-landscape · Track: Think · Level: Foundation · Facts last checked 6 October 2026

Read first: [Microcontroller or microprocessor?](https://dharanova.com/learn/mcu-vs-mpu.md)

Diagram: Three rows. Arm designs cores in three profiles, A for applications, R for real-time and M for microcontrollers, and licenses them to many chip vendors; since 2026 Arm also sells one data-centre CPU of its own. RISC-V is an open standard kept by RISC-V International; anyone may implement it with no ISA licence fee, with their own design or a licensed core, and RVA23 (2024) is a baseline for application processors. Intel and AMD design and sell their own x86-64 chips. Also: Xtensa, owned by Cadence, and MIPS, an older architecture in billions of shipped chips, now moved to RISC-V.

## Key points

1. Arm defines three architecture profiles, each implemented by a Cortex family: A-profile (Cortex-A) for application processors running rich operating systems, R-profile (Cortex-R) for real-time systems, and M-profile (Cortex-M) for microcontrollers. [1][2]
2. Arm designs processor cores and licenses them to chip vendors, so many companies ship chips built on the same Arm cores. For most of its history Arm sold no chips of its own; in March 2026 it launched its first, a data-centre CPU. (as of 6 October 2026) [3][4]
3. RISC-V is an open instruction set standard maintained by RISC-V International; anyone may implement it without paying an ISA licence fee, though individual core designs may still be commercially licensed. [5]
4. RVA23, ratified in October 2024, is the RISC-V application-processor profile that sets a common baseline of extensions (including vector) for operating systems and software to target. [6]
5. Xtensa is a configurable processor architecture whose instruction set is owned by Cadence. It is the main CPU in some Wi-Fi microcontrollers, although at least one major Wi-Fi MCU family has moved its newer chips to RISC-V. [7][8][9]
6. x86-64 processors from Intel and AMD are used in embedded systems where PC software compatibility, high performance or virtualisation matter more than power or cost. [10][11]
7. MIPS is an older architecture found in billions of shipped chips. The company behind it switched its new processor designs to RISC-V in 2022, and was acquired by GlobalFoundries in August 2025. (as of 6 October 2026) [12][13][14]

## Sources

1. [CPU Architecture: A-profile, R-profile and M-profile](https://www.arm.com/architecture/cpu), Arm
2. [Armv7-M Architecture Reference Manual (DDI0403E.e)](https://support.arm.com/documentation/ddi0403/ee/), Arm
3. [Arm licensing models](https://www.arm.com/products/licensing), Arm
4. [Arm expands compute platform to silicon products in historic company first](https://newsroom.arm.com/news/arm-agi-cpu-launch), Arm
5. [About RISC-V International](https://riscv.org/about/), RISC-V International
6. [RISC-V Announces Ratification of the RVA23 Profile Standard](https://riscv.org/blog/risc-v-announces-ratification-of-the-rva23-profile-standard/), RISC-V International
7. [Overview of Xtensa ISA](https://dl.espressif.com/github_assets/espressif/xtensa-isa-doc/releases/download/latest/Xtensa.pdf), Espressif
8. [ESP32-S3 datasheet](https://documentation.espressif.com/esp32-s3_datasheet_en.pdf), Espressif
9. [ESP32-C6 datasheet](https://documentation.espressif.com/esp32-c6_datasheet_en.pdf), Espressif
10. [Intel Atom x7425E Processor](https://www.intel.com/content/www/us/en/products/sku/233093/intel-atom-x7425e-processor-6m-cache-up-to-3-40-ghz/specifications.html), Intel
11. [AMD Ryzen Embedded Family](https://www.amd.com/en/products/embedded/ryzen.html), AMD
12. [MIPS Corporate Overview](https://mips.com/wp-content/uploads/2024/01/MIPS-Corporate-Overview-FINALdocx.pdf), MIPS
13. [MIPS Pivots to RISC-V with Best-In-Class Performance and Scalability](https://mips.com/press-releases/mips-pivots-to-risc-v-with-best-in-class-performance-and-scalability/), MIPS
14. [GlobalFoundries Completes Acquisition of MIPS](https://gf.com/gf-press-release/globalfoundries-completes-acquisition-of-mips/), GlobalFoundries