User guide

System Control

ID072410 Non-Confidential

4.3 Register descriptions

This section describes the system control registers whose implementation is specific to this

processor.

4.3.1 Auxiliary Control Register, ACTLR

The ACTLR characteristics are:

Purpose Disables certain aspects of functionality within the processor.

Usage Constraints There are no usage constraints.

Configurations This register is available in all processor configurations.

Attributes See the register summary in Table 4-1 on page 4-3.

Figure 4-1 shows the ACTLR bit assignments.

Figure 4-1 ACTLR bit assignments

Table 4-2 shows the ACTLR bit assignments.

4.3.2 CPUID Base Register, CPUID

The CPUID characteristics are:

Purpose Specifies:

• the ID number of the processor core

• the version number of the processor core

• the implementation details of the processor core.

Usage Constraints There are no usage constraints.

Configurations This register is available in all processor configurations.

Attributes See the register summary in Table 4-1 on page 4-3.

Reserved

31 3210

DISFOLD

DISDEFWBUF

DISMCYCINT

Table 4-2 ACTLR bit assignments

Bits Name Function

[31:3] - Reserved

[2] DISFOLD Disables folding of

instructions.

[1] DISDEFWBUF Disables write buffer use during default memory map accesses. This causes all bus faults to be precise,

but decreases the performance of the processor because stores to memory must complete before the

next instruction can be executed.

[0] DISMCYCINT Disables interruption of multi-cycle instructions. This increases the interrupt latency of the processor

because load/store and multiply/divide operations complete before interrupt stacking occurs.