3.2.14. c0, Memory Model Feature Register 3

The purpose of the Memory Model Feature Register 3 is to provide information about the memory model, memory management, cache support, and TLB operations of the processor.

The Memory Model Feature Register 3 is:

Figure 3.10 shows the bit arrangement of the Memory Model Feature Register 3.

Figure 3.10. Memory Model Feature Register 3 format


Table 3.25 shows how the bit values correspond with the Memory Model Feature Register 3 functions.

Table 3.25. Memory Model Feature Register 3 bit functions

BitsFieldFunction

[31:28]

Supersection

Indicates support for supersections:

0x0 = Processor supports supersections.

[27:12]

-

Reserved, RAZ.

[11:8]

Branch predictor maintenance

Indicates support for branch predictor maintenance operations:

0x2 = Processor supports invalidate entire branch predictor array and invalidate branch predictor by MVA.

[7:4]

Hierarchical cache maintenance operations by set and way

Indicates support for invalidate cache by set and way, clean by set and way, and invalidate and clean by set and way:

0x1 = Processor supports invalidate cache by set and way, clean by set and way, and invalidate and clean by set and way.

[3:0]

Hierarchical cache maintenance operations by MVA

Indicates support for invalidate cache by MVA, clean by MVA, invalidate and clean by MVA, and invalidate all:

0x1 = Processor supports invalidate cache by MVA, clean by MVA, invalidate and clean by MVA, and invalidate all.


Table 3.26 shows the results of attempted access for each mode.

Table 3.26. Results of access to Memory Model Feature Register 3[13]

Secure privilegedNonsecure privilegedSecure UserNonsecure User
ReadWriteReadWriteReadWriteReadWrite
DataUndefinedDataUndefinedUndefinedUndefinedUndefinedUndefined

[13] An entry of Undefined in the table means that the access gives an Undefined Instruction exception when the coprocessor instruction is executed.


To access the Memory Model Feature Register 3, read CP15 with:

MRC p15, 0, <Rd>, c0, c1, 7 ; Read Memory Model Feature Register 3
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