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PMMIR, Performance Monitors Machine Identification Register

The PMMIR characteristics are:


Describes Performance Monitors parameters specific to the implementation.


PMMIR is in the Core power domain.

This register is present only when FEAT_PMUv3p4 is implemented. Otherwise, direct accesses to PMMIR are RES0.


PMMIR is a 32-bit register.

Field descriptions

The PMMIR bit assignments are:


Bits [31:8]

Reserved, RES0.

SLOTS, bits [7:0]

Operation width. The largest value by which the STALL_SLOT event might increment by in a single cycle. If the STALL_SLOT event is implemented, this field must not be zero.

Accessing the PMMIR

If the Core power domain is off or in a low-power state, access on this interface returns an Error.

PMMIR can be accessed through the external debug interface:


This interface is accessible as follows:

  • When !IsCorePowered(), or DoubleLockStatus(), or OSLockStatus() or !AllowExternalPMUAccess() accesses to this register generate an error response.
  • Otherwise accesses to this register are RO.