This is the third episode in a series on bare metal programming on the Raspberry Pi. This episode rounds out my initial stab at doing a series on RPI embedded programming based on my summer vacation project. This episode discusses how to write code with an eye towards using it in an embedded environment. It continues with a discussion of how coprocessors fit into the ARM architecture. It also describes how to manage coprocessors programatically in a very hackerish way using self-modifying code. Finally, the episode describes how to enable the virtual memory subsystem in the ARM as well as the cache. It includes some performance measurements of my code both with and without the cache enabled.

Here is some of the source material that I reference in this episode. See the previous episode show notes for information on how to get your own bare metal Raspberry Pi setup up and running.

CATRPI

• Homepage: https://gitorious.org/catrpi
• Git repo: git://gitorious.org/catrpi/catrpi.git
• My own repository of code that I wrote during this little project.

Hacker's Delight by Henry S. Warren Jr.

• https://www.hackersdelight.org/
• A fantastic book on low level computer mathematics. I find it a joy to read. I cannot recommend it highly enough. It belongs on anyone's shelf next to Knuth and other "programming bibles".

ARM ARM

• https://www.scss.tcd.ie/~waldroj/3d1/arm_arm.pdf
• https://morrow.ece.wisc.edu/ECE353/arm_reference/ddi0100e_arm_arm.pdf
• Contains the ARM assembly language as well as chip architecture overview.
• You'll need the ARM 11 Architecture Reference Manual

ARM TRM

• https://infocenter.arm.com/help/topic/com.arm.doc.ddi0301h/DDI0301H_arm1176jzfs_r0p7_trm.pdf
• Contains info about the specific SOC that the Raspberry PI uses

dwelch67's bare metal repository

• As always, the best guide I know on this topic. Very thorough and what I used as my starting point.
• https://github.com/dwelch67/raspberrypi