a quick getting started hack to debug all the user issues.
TODO:
-- bourne shell crashes when you type a command (known to have 16bit-isms,
+- bourne shell crashes on exit (known to have 16bit-isms,
may be worth running the slightly bigger 'Heritage' /bin/sh with SYS5 type
features instead
-- date gives bogus results, probably some sizing issues
- signal handling needs further testing (disabled on IRQ path currently)
- copy exception/trap frames onto user stack along with trap identifiers
- so we can support stuff like CP/M68K emulators.
+ so we can support stuff like CP/M 68K and TOS emulators.
- pre-emption needs more testing (also disabled on IRQ path currently)
- support multiple IRQ sources and IRQ priority nesting when appropriate
- enable IRQ during swap on context switch