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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors—Intel XScale
®
Processor
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
Developer’s Manual
August 2006
100
Order Number: 306262-004US
3.5.1.2
Register 1: Control and Auxiliary Control Registers
Register 1 is made up of two registers, one that is compliant with Intel
®
StrongARM
*
Version 5TE and referred by opcode_2 = 0x0, and the other which is specific to the
Intel XScale processor is referred by opcode_2 = 0x1. The latter is known as the
Auxiliary Control Register.
The Exception Vector Relocation bit (bit 13 of the Intel
®
StrongARM
*
control register)
allows the vectors to be mapped into high memory rather than their default location at
address 0. This bit is readable and writable by software. If the MMU is enabled, the
exception vectors will be accessed via the usual translation method involving the PID
“Register 13: Process ID” on page 106
) and the TLBs. To avoid automatic
application of the PID to exception vector accesses, software may relocate the
exceptions to high memory.
5:3
Read / Write Ignored
Instruction cache associativity = 0b101 = 32-way
2
Read-as-Zero / Write Ignored
Reserved
1:0
Read / Write Ignored
Instruction cache line length = 0b10 = 8 words/line
Table 13.
Cache Type Register (Sheet 2 of 2)
31 30 29 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
0 0 0 0 1 0 1 1 0 0 0
Dsize
1 0 1 0 1 0 0 0 0
Isize
1 0 1 0 1 0
reset value: As Shown
Bits
Access
Description
Table 14.
Intel
®
StrongARM
*
Control Register (Sheet 1 of 2)
31 30 29 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
V I Z 0 R S B 1 1 1 1 C A M
reset value: writable bits set to 0
Bits
Access
Description
31:14
Read-Unpredictable /
Write-as-Zero
Reserved
13
Read / Write
Exception Vector Relocation (V).
0 = Base address of exception vectors is 0x0000,0000
1 = Base address of exception vectors is 0xFFFF,0000
12
Read / Write
Instruction Cache Enable/Disable (I)
0 = Disabled
1 = Enabled
11
Read / Write
Branch Target Buffer Enable (Z)
0 = Disabled
1 = Enabled
10
Read-as-Zero / Write-as-Zero
Reserved
9
Read / Write
ROM Protection (R)
This selects the access checks performed by the memory
management unit. See the ARM* Architecture Reference
Manual for more information.
8
Read / Write
System Protection (S)
This selects the access checks performed by the memory
management unit. See the ARM* Architecture Reference
Manual for more information.
7
Read / Write
Big- / Little-Endian (B)
0 = Little-endian operation
1 = Big-endian operation
6:3
Read-as-One / Write-as-One
= 0b1111