5.8.1. Enabling trace

When TraceEnable becomes active during a trace run, tracing is enabled. The trace port outputs a BE status, and associated with it is a 5-packet address. This provides a start address so that the trace information can be successfully decompressed from the first instruction after the trace is enabled. This indicates to the trace decompressor software that there is a discontinuity in the trace. A correct address packet offset must be generated, because the FIFO might not be empty at the point when tracing has been enabled.

In ETMv1.3, bit [7] of the fifth address packet indicates the state of the J-bit for the instruction where tracing is enabled.

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