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by monocasa 2315 days ago
You'd be surprised how true that is today too.

The Wii and WiiU run most of the "OS" on an external ARM core "Starlet"/"Starbuck". All I/O, network access, encryption for SSL, booting the main cores, the USB stack, etc. is on that ARM core, not the main PowerPC cores so those can be dedicated to running "game code".

The Cell in the PS3 is a SPI slave that gets booted by an external processor.

The PS4 is the same way, and that external core holds most of the filesystem (how game updates happen with the console "off").

And then most SoCs (including most AMD and Intel chips) boot system management cores (ME/PSP/etc.) that then is responsible for initializing the rest of the core complexes on the chip. Pretty much every ARM SoC sold these days will talk about how they have a CortexM3 in addition to they CortexA cores; that's what it's for. SiFive's Linux capable chip has one of their E series cores in addition to their U series cores for the same purpose on the RISC-V side of things.

1 comments

> Pretty much every ARM SoC sold these days will talk about how they have a CortexM3 in addition to they CortexA cores; that's what it's for.

Usually the advertised-on-the-datasheet M cores are available for user code and you'll get a virtual serial port or some shared memory to go between them and the big core. I don't doubt that there are additional hidden cores taking care of internal power management, early boot etc.

At least, this is how it is on the STM32MP1 and the TI Sitara AM5 socs.