Went with the hybrid proposal, and it works perfectly (AFAIT*) on
the host now. I'll try to test the i386 boot out sometime tonight. The
native code support is activated with the -DNEW_INTERRUPT_HANDLING flag,
but the bytecode support is radically different, to the extent that I had
to make a new bytecode tree and compile against that. Once I bring that
tree up to snuff, I'll just move into where the old tree was and finally
do a CVS commit and the thing.
Driver writers: the new interrupt paradigm is straight
event-based, with jos.system.interrupts using addInterruptListener() in
the usual way, with one exeption. When the interpreter finishes the
current timeslice, it checks the interrupt queue; while it's not empty,
the C code will extract your driver objects from jos.system.interrupts and
run its handleInterrupt ( int interrupt_number ) code from there. This
code will run, uninterrupted -- including by other interrupts -- until it
completes, so be very careful with it. Get your data from the h/w in that
function and let another thread take care of the analysis, if at all
possible. (The keyboard driver, for instance, (will) slurps scancodes out
of the controller and shoves them into a queue, where the keyboard daemon
can play with them, distribute them, etc.)
My model, in general, is that jos.platform.* is limited to
abstractions common across every computer JOS will run on, like keyboards
(even if they aren't there). jos.platform.keyboard generates Key and
Scancode events, but jos.platform.driver.keyboard (& keyboardd) is what
handles the hardware (lower-edge) part of the driver. The
platform.drivers are expected to use jos.system.* (probably should be
renamed) to access the h/w, via the interrupts and machine classes, and
more as we need them.
Thus jos.platform.screen would be driven by
jos.platform.driver.screen, which would just be Thomas Bocek's VGA driver
class (or a wrapper there-to). jos.platform.driver.* will be copied over
from arch/bytecode/jos/platform/driver/* according the current build, so
that's how we get h/w-specificity.
jos.platform == JOSSystem and jos.system == JOSBox, I believe,
though I haven't read their descriptions recently enough to be sure.
Comments? (Suggestions? Flames?)
-_Quinn
* As Far As I Tested
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