Fix DIV of a negative value
Factor out register writes

Register writes always affect the Z/N flags, even when a BL instruction writes
R15.
Rename the I/O functions
Replace gettimeofday by SDL_GetTicks
Press F12 to reset your RISC
Add current status to readme
Document F12
Fix start-up flicker
Some more emulation bugs + small cleanups

Many CPU features seem to be completely unused by Oberon?
Implement the floating instructions.

This is a pretty literal translation of the Verilog code. This received
minimal testing, there are certainly bugs here.
Enable more compiler warnings
Paul Reed's implementation of the PCLink RS232 protocol
Full-screen display

Use --fullscreen command line option or press F11 to toggle.
Use alt key to emulate middle button click (Paul Reed)
copyright
typo
Implement Cmd-Shift-F for Mac users. I hope this works.