Apple is fully moving its embedded cores to the RISC-V architecture

It was reported last year that Apple is recruiting programmers for the RISC-V architecture, mainly responsible for the design and related improvements of various embedded subsystems running on iOS, macOS, watchOS, and tvOS. According to the job description, candidates also need to understand machine learning, computational vision, and natural language processing technologies, as well as a solid understanding of Arm’s extended architecture, Neon. At that time, someone saw from the job description that Apple already had RISC-V architecture devices in operation.

Image: semianalysis

According to SemiAnalysis, Apple is fully moving its embedded cores to the RISC-V architecture. At present, in Apple’s M-series processors, in addition to the main core, there are a large number of embedded auxiliary cores. For example, there are more than 30 in M1, responsible for various workloads independent of the operating system, including Wi-Fi/Bluetooth, touchpad control, thunderbolt interface, etc. These embedded auxiliary cores run their own firmware, powering the perimeter around the main core running the operating system.

This type of embedded auxiliary core is often based on Arm’s Cortex-M series or low-end Cortex-A series cores, which Apple is replacing with RISC-V architecture cores. Since most of the embedded auxiliary cores of these functional modules have a single function, Apple can re-adapt with a slight adjustment in the firmware. With the scale and capability of Apple’s engineering team, it is not difficult to do so.

Today, Apple uses a large number of Arm architecture processors and needs to pay a large licensing fee. With the further development of Apple’s self-developed chips, the number will continue to increase in the future, and the cost will also rise.
If the embedded auxiliary core is replaced with a RISC-V architecture core, Apple can save a lot of money due to its license-free and open-source features.

It is not clear when Apple will fully transfer the embedded kernel to the RISC-V architecture, after all, Apple will not issue an official announcement for this. On the one hand, its self-developed M-series processors are still based on the Arm architecture on the main core, and on the other hand, all the contents of these embedded auxiliary cores are invisible to users.