6.5. CDP

CDP instructions normally execute in a single cycle. Like all the previous cycles, nCPMREQ is driven LOW to signal when an instruction is entering the decode and then the execute stage of the pipeline:

Figure 6.4 shows a CDP which is cancelled due to the previous instruction causing a Data Abort.

Figure 6.4. Late cancelled CDP

The CDP instruction enters the execute stage of the pipeline and is signaled to execute by CPASS. In the following cycle CPLATECANCEL is asserted. This causes the coprocessor to terminate execution of the CDP instruction and for it to cause no state changes to the coprocessor.

Copyright © 1999 ARM Limited. All rights reserved.ARM DDI 0164A