ARM R4 Manuale Utente
System Control Coprocessor
ARM DDI 0363E
Copyright © 2009 ARM Limited. All rights reserved.
4-18
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MRC p15, 0, <Rd>, c0, c0, 4 ; Returns MPU details
4.2.6
c0, Multiprocessor ID Register
The Multiprocessor ID Register enables cores to be recognized and characterized within a
multiprocessor system.
multiprocessor system.
The Multiprocessor ID Register is:
•
•
read-only register
•
accessible in Privileged mode only.
Figure 4-11 shows the arrangement of bits in the register.
Figure 4-11 Multiprocessor ID Register format
Because this is a uniprocessor system, this register is Read-As-Zero.
To access the Multiprocessor ID Register, read CP15 with:
MRC p15, 0, <Rd>, c0, c0, 5 ; Returns Multiprocessor ID details
4.2.7
The Processor Feature Registers
There are two Processor Feature Registers, PFR0 and PFR1. This section describes:
•
•
•
c0, Processor Feature Register 0, PFR0
The Processor Feature Register 0 provides information about the execution state support and
programmer’s model for the processor.
programmer’s model for the processor.
Processor Feature Register 0 is:
•
•
a read-only register
•
accessible in Privileged mode only.
Figure 4-12 shows the bit arrangement for Processor Feature Register 0.
Figure 4-12 Processor Feature Register 0 format
Affinity Level 2
Reserved
31
16
8 7
0
Affinity Level 0
Affinity Level 1
24 23
Reserved
State3
31
16 15
8 7
3
0
State2
State1
State0
4
11
12