Adds (most) support for ARC platform to port-independent mips code.
Some changes (e.g., clean up of overlapping CPU/FPU ids) inspired by
comparison to the OpenBSD 2.1 codebase of Soda's ARC port.
Open issues:
* Still no support for r4600 or mipsIV CPUs with two-way L1 cache.
Code derived from Per Fogelstrom's OpenBSD source doesn't work
on mips3 pmaxes with L2 cache.
* Still some port-specific #ifdefs, for interrupt enable and
pmax L2 cache-size. Needs more thought, but overlaps with
work-in-progress by Tohru and Tsubai on spl()s and related stuff.
in length when readline is used (rl_len was a *char*!!!). Undo disabling
of readline (this fix was like ``finger hurts, cut hand'') I guess PR/5793
is already closed...
* Increase the size of sigset_t to accomodate 128 signals -- adding new
versions of sys_setprocmask(), sys_sigaction(), sys_sigpending() and
sys_sigsuspend() to handle the changed arguments.
* Abstract the guts of sys_sigaltstack(), sys_setprocmask(), sys_sigaction(),
sys_sigpending() and sys_sigsuspend() into separate functions, and call them
from all the emulations rather than hard-coding everything. (Avoids uses
the stackgap crap for these system calls.)
* Add a new flag (p_checksig) to indicate that a process may have signals
pending and userret() needs to do the full (slow) check.
* Eliminate SAS_ALTSTACK; it's exactly the inverse of SS_DISABLE.
* Correct emulation bugs with restoring SS_ONSTACK.
* Make the signal mask in the sigcontext always use the emulated mask format.
* Store signals internally in sigaction structures, rather than maintaining a
bunch of little sigsets for each SA_* bit.
* Keep track of where we put the signal trampoline, rather than figuring it out
in *_sendsig().
* Issue a warning when a non-emulated sigaction bit is observed.
* Add missing emulated signals, and a native SIGPWR (currently not used).
* Implement the `not reset when caught' semantics for relevant signals.
Note: Only code touched by the i386 port has been modified. Other ports and
emulations need to be updated.
