Table 3-44 Coprocessor Access Control Register Bit Functions; Table 3-45 Results Of Access To The Coprocessor Access Control Register; Figure 3-28 Coprocessor Access Control Register Format - ARM ARM1176JZF-S Technical Reference Manual

3.2.9 c1, Coprocessor Access Control Register
Bits
[31:28]
-
a. n is the coprocessor number between 0 and 13.
Corresponding bit in Non-Secure
Access Control Register
0
1
ARM DDI 0301H
ID012310
The purpose of the Coprocessor Access Control Register is to set access rights for the
coprocessors CP0 through CP13. This register has no effect on access to CP14, the debug
control coprocessor, or CP15, the system control coprocessor. This register also provides a
means for software to determine if any particular coprocessor, CP0-CP13, exists in the system.
The Coprocessor Access Control Register is:
• in CP15 c1
• a 32-bit read/write register common to Secure and Non-secure worlds
• accessible in privileged modes only.
Figure 3-28 shows the arrangement of bits in the register.
28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
31
SBZ/UNP cp13 cp12 cp11 cp10 cp9
Table 3-44 lists how the bit values correspond with the Coprocessor Access Control Register
functions.
Field name Function
- UNP/SBZ.
a Defines access permissions for each coprocessor.
cp<n>
Access denied is the reset condition.
Access denied is the behavior for non-existent coprocessors:
b00 = Access denied, reset value. Attempted access generates an Undefined exception
b01 = Privileged mode access only
b10 = Reserved.
b11 = Privileged and User mode access.
Access to coprocessors in the Non-secure world depends on the permissions set in the c1,
Non-Secure Access Control Register on page 3-55.
Attempts to read or write the Coprocessor Access Control Register access bits depend on the
corresponding bit for each coprocessor in c1, Non-Secure Access Control Register on page 3-55.
Table 3-45 lists the results of attempted access to coprocessor access bits for each mode.

Table 3-45 Results of access to the Coprocessor Access Control Register

Secure Privileged
Read
Data
Data
To use the Coprocessor Access Control Register read or write CP15 with:
• Opcode_1 set to 0
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cp8 cp7

Figure 3-28 Coprocessor Access Control Register format

Table 3-44 Coprocessor Access Control Register bit functions

Non-secure Privileged
Write Read
Data b00
Data Data
System Control Coprocessor
cp6 cp5 cp4 cp3 cp2
User
Write
Ignored Undefined exception
Data Undefined exception
cp1 cp0
3-51