Coprocessor 15
2-14
Table 2–6. CP15 Cache Information Register (CIR) (Continued)
Bit
Function
Value
Name
2
I-cache information
Parameter to calculate the real I-cache associativity and size:
0
I-cache associativity and I-cache size are equal to the base
value.
1
I-cache associativity and I-cache size are equal to 3/2 of the
base value. Exception: If base value of associativity is 1, a 1
indicates here that there is no I-cache; 0 indicates that I-cache is
really direct-map.
1–0
I-cache information
Indicates line length of the I-cache
:
00
8 bytes
01
16 bytes
10
32 bytes
11
64 bytes
This register specifies the configuration of the TI925T core. It is recommended
that the register be written using a read-modify-write routine.
Reading from CP15 register 1 reads the control bits. The CRm and opcode_2
fields are ignored when reading CP15 register 1, but must be zero.
Writing to CP15 register 1 sets the control bits. The CRm and opcode_2 fields
are not used when writing CP15 register 1, but must be zero.
All control bits but V are set to zero upon reset.
Table 2–7. CP15 Control Register
Bit
Name
Value
Function
31–15
Reserved: Do not rely on any particular value in these bit locations
during a read (ensure they are masked properly). Write these bits as
zero.
14
0
Read as 0. Write is ignored.
13
V
Alternate vector select. Sets the address of the exception vector from
address 0x00000000 to 0x0000001F when at zero and from
0xFFFF0000 to 0xFFFF001F when at 1. This bit takes the value of the
HIVECS signal port upon reset. After reset, it can be changed by
software.