Reading from CP15 Register 13 with opcode_2 = 0 returns the value of the Fast Context Switch Extension (FCSE) Process IDentifier (PID). FCSCE PID Register format is shown in Figure 3.10.

Writing to CP15 Register 13 with opcode_2 = 0 updates the FCSE PID from the value in bits [31:25]. Bits [24:0] Should Be Zero. The FCSE PID is set to b0000000 on Reset.

The CRm and opcode_2 Should Be Zero when reading or writing the FCSE PID.

You must take care when changing the FCSE PID because the following instructions have been fetched with the previous FCSE PID. In this way, changing the FCSE PID has similarities with a branch with delayed execution. See Relocation of low virtual addresses by the FCSE PID.

A 32-bit read/write register is provided to hold a Trace PROCess IDentifier (PROCID) up to 32-bits in length visible to the ETM7. This is achieved by reading from or writing to the PROCID Register with opcode_2 set to 1. PROCID Register format is shown in Figure 3.11.

The PROCIDWR signal is exported to notify the ETM7 that the Trace PROCID has been written.