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TRACING AND DEBUGGING
9.5.2.2
Tracing on Implicit Call
Tracing on an implicit call happens before execution of the first instruction of the non-trace fault
handler called.
Table 9-6
summarizes all cases of tracing on implicit call. In the table, a is a bit
variable that symbolizes the trace enable bit in PC.
Call
Type
1
00-Fault
1
10-Fault
1
10-Fault
00-Parallel/Override Fault
00-Trace Fault
10-Parallel/Override Fault
10-Trace Fault
10-Parallel/Override Fault
10-Trace Fault
Interrupt
1. On i960 Jx processor, all faults except parallel/override and trace faults.
2. "x" and "a" are bit variables.
Tracing is not altered on the way to a local or a system-local fault handler, so the call is traced if
PC.te and TC.c are set before the call. For an implicit system-supervisor call, PC.te is read from the
Supervisor Stack Pointer enable bit (SSP.te). The trace on the call is serviced before execution of the
first instruction of the non-trace fault handler (tracing is disabled on the way to a trace fault handler).
On the i960 Jx processor, the parallel/override fault handler must be accessed through a
system-supervisor call. Tracing is disabled on the way to the parallel/override fault handler.
The only type of trace fault handler supported is the system-supervisor type. Tracing is disabled on
the way to the trace fault handler.
Tracing is disabled by the processor on the way to an interrupt handler, so an interrupt call is never traced.
Note that the Fault IP field of the fault record is not defined when tracing a fault call, because there
is no instruction pointer associated with an implicit call.
9-14
Table 9-6. Tracing on Implicit Call
Previous
System
Frame
Procedure
Pointer
Table Entry
Return Status
(PFP.rt[2:0])
N.A.
001
2
00
001
2
2
10
001
2
2
2
x
Type of trace fault not supported
00
Type of trace fault not supported
2
10
001
2
2
N.A.
111
2
PC.te Value
Source
Target
Used for
PC.te
PC.te
Traces on
Implicit Call
2
2
a
a
a
2
2
a
a
a
2
a
SSP.te
SSP.te
2
a
0
2
a
0
2
2
0
0
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