EM instructions _rol_ and _ror_ do rotate an integer left or right.
Our compilers and optimizers never emit _rol_ nor _ror_, but I might
want to use them in the future.
Add _rol_ and _ror_ to powerpc. Fix `rol 4` and `ror 4` in both i80
and i86, where the rules for `rol 4` and `ror 4` seem to have never
been tested until now.
My computer is too slow, so qemuppc tests randomly timed out. With
this commit, my machine passes the qemuppc tests (if I also edit the
top build.lua to enable qemuppc).
A `set -e` in testdriver.sh caused it to exit early and hide the
output of a @@TIMEDOUT test, so I never saw the @@TIMEDOUT marker.
Then build.lua added a @@FAIL marker.
was nearly useless; lots of fixes to qemuppc and pc86 sbrk(), which was broken;
change the pc86 console to echo output to the serial port (needed for running
tests on qemu).
