4.11.2. Coprocessor data transfer

A Coprocessor Data Transfer (CPDT) occurs when the processor executes an LDC or STC instruction. CPDT instructions are treated in the same way as standard processor loads and stores. Only when you analyze the disassembled trace information can you determine that the data access involved a coprocessor.

ETMv1

In ETMv1, it is important that the number of words transferred for an LDC or STC instruction can be statically determined from the instruction. To do this, the decompressor requires specific knowledge of the coprocessor involved because the number of data packets is not directly encoded in the instruction but is determined by the coprocessor during execution of the instruction. The debugger must be aware of this mapping.

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