cowlark.com :  PiFace v0.3

PiFace v0.3

a bare-metal boot loader for the Raspberry Pi's VideoCore IV GPU

Published: 2013 November 26

I actually did this a while ago but forgot to post it here...

This is a boot loader for the Raspberry Pi which runs directly on the VideoCore IV GPU. The ARM processor is not involved in any way. It allows you to play with the Raspberry Pi bare metal. It provides a serial port console and functionality for uploading and downloading data, access to files on the SD card, etc.

It was compiled with a pretty shonky VideoCore IV port of the Amsterdam Compiler Kit --- there is no gcc or LLVM port yet. Right now the feature set is pretty thin because there's still a lot of stuff which isn't known about the VideoCore, but there's still enough to be really useful if you're interested in investigating the VideoCore.