System Control
ARM DDI 0500D
Copyright © 2013-2014 ARM. All rights reserved.
4-210
ID021414
Non-Confidential
[11]
-
Reserved,
RES
1.
[10:9]
- Reserved,
RES
0.
[8]
SED
SETEND Disable:
0
The SETEND instruction is available.
1
The SETEND instruction is UNALLOCATED.
[7]
ITD
IT Disable:
0
The IT instruction functionality is available.
1
All encodings of the IT instruction with hw1[3:0]!=1000 are
UNDEFINED
and treated as
unallocated. All encodings of the subsequent instruction with the following values for hw1 are
UNDEFINED
(and treated as unallocated):
11xxxxxxxxxxxxxx
All 32-bit instructions, B(2), B(1), Undefined, SVC, Load/Store multiple
1x11xxxxxxxxxxxx
Miscellaneous 16-bit instructions
1x100xxxxxxxxxxx
ADD Rd, PC, #imm
01001xxxxxxxxxxx
LDR Rd, [PC, #imm]
0100x1xxx1111xxx
ADD(4),CMP(3), MOV, BX pc, BLX pc
010001xx1xxxx111
ADD(4),CMP(3), MOV
[6]
-
Reserved,
RES
0.
[5]
CP15BEN
CP15 barrier enable:
0
CP15 barrier operations disabled. Their encodings are
UNDEFINED
.
1
CP15 barrier operations enabled.
[4:3]
-
Reserved,
RES
1.
[2]
C
Cache enable. This is an enable bit for data and unified caches at EL2:
0
Data and unified caches disabled at EL2.
1
Data and unified caches enabled at EL2.
When this bit is 0, all EL2 Normal memory data accesses and all accesses to the EL2 translation tables are
Non-cacheable.
If this register is at the highest exception level implemented, field resets to 0. Otherwise, its reset value is
UNKNOWN
.
[1]
A
Alignment check enable. This is the enable bit for Alignment fault checking:
0
Alignment fault checking disabled.
1
Alignment fault checking enabled.
When this bit is 1, all instructions that load or store one or more registers, other than load/store exclusive and
load-acquire/store-release, have an alignment check that the address being accessed is aligned to the size of
the data element(s) being accessed. If this check fails it causes an Alignment fault, that is taken as a Data Abort
exception.
Load/store exclusive and load-acquire/store-release instructions have this alignment check regardless of the
value of the A bit.
If this register is at the highest exception level implemented, field resets to 0. Otherwise, its reset value is
UNKNOWN
.
Table 4-201 HSCTLR bit assignments (continued)
Bits
Name
Function