This is the third "generation" of Riscy Pygness.
Generation 1 worked with the NXP lpc2106 with a smart terminal that downloaded incrementally-defined words to the target's flash. It included support for an MMC/SD disk (using the SPI interface), including some FAT16 support.
Generation 2 attempted to eliminate the need for the smart terminal by storing heads on the target and providing the target with the ability to do (some) of its own compiling. I now think this is a bad idea and that the appeal of "works with any serial terminal" is without substance. Who these days uses "any" serial terminal rather than a PC or desktop workstation of some sort?
Generation 3 is the current version. I am developing primarily on the Olimex LPC P-2378 development board with an NXP lpc2378 CPU and/or the LPC P-2103. The code specific to the lpc2378 has been factored into custom-lpc23xx.asm. The code specific to the lpc2106 has been factored into custom-lpc2106.asm. The code specific to the lpc2103 has been factored into custom-lpc2103.asm. The main assembly language source code, riscy.asm, has include statements for one or the other of these two files. It is a simple matter to write other CPU-specific or board-specific files for different boards or processors.
Since the lpc2378 includes a built-in MMC/SD interface, my plan is to use that instead of the generic SPI interface. This is not ready yet. The download includes the MMC/SD code that worked on the lpc2106 but it may need to be revised somewhat to work with generation 3.