interrupting user mode. The net effect of this bug is that a clock
interrupt does not cause rescheduling and processes are not
preempted. It only takes a "while (1);" to render the machine
useless.
This bug was introduced by the context changes and EPC syscall code.
Handling of ASTs was moved to C for clarity and ease of maintenance,
but was not added for the external interrupt case.
This needs to be revisited. We now have calls to do_ast() in trap(),
break_syscall() and ivt_External_Interrupt(). A single call in
exception_restore covers these 3 places without duplication. This
is where we handled ASTs prior to the overhaul, except that the
meat has been moved to do_ast(), a C function. This was the goal
to begin with.
Pointy hat: marcel
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