#Software Error Requeste
25-Feb-86 01:56:49
Sb: #9029-#Software Error Requeste
Fm: Carl Sassenrath 72407,1230
To: Mike Duffy 75026,3263
This message turned up in search, but its forum couldn’t be identified from the original transcript, so it may not be linked into its thread.
Here's what happens:
1. some sort of 68000 occurs, say and address error;
2. control is vectored to Exec in supervisor mode;
3. Exec determines whether the exception occurred in
user mode (a task) or super mode (internal error).
4. If it was a task, then control is vectored to the
tasks TrapCode routine (notice that it is called a
"trap" at this point, Task Exceptions are more like
task context interrupts… for things like Try/Recover,
and Catch/Throw).
5. If the task did not supply a Trap vector, the system
default is used. If the Task is a user Process, the
task held requestor is generated. It the Task is an
internal operation (device usually), Exec turns to
the Guru.
What does this mean? Sure, you can handle your own Traps
(68000 exceptions) for your user Process and avoid the
task held message. -Carl-