The ARM922T coprocessor 15 (CP15), register 15 (c15) is used to provide additional device-specific test operations. You can use it to access and control the following:

You must only use these operations for test. The ARM Architecture Reference Manual describes this register as implementation defined.

The format of the CP15 test operations is:

MCR/MRC  p15,opcode_1,Rd,c15,CRm,opcode_2

The L bit distinguishes between an MCR (L = 1) and an MRC (L = 0).