Jazelle DBX registers
ARM DDI 0388I
Copyright © 2008-2012 ARM. All rights reserved.
5-7
ID073015
Non-Confidential
To access the JMCR, read or write the CP14 register with:
MRC p14, 7, <Rd>, c2, c0, 0; Read JMCR
MCR p14, 7, <Rd>, c2, c0, 0; Write JMCR
5.3.4
Jazelle Parameters Register
The Jazelle Parameters Register characteristics are:
Purpose
Describes the configuration parameters of the Jazelle hardware.
Usage constraints
Only accessible in privileged modes.
Configurations
Available in all configurations.
Attributes
See the register summary in
.
shows the Jazelle Parameters Register bit assignments.
Figure 5-4 Jazelle Parameters Register bit assignments
[27]
IS
The
Index Size
(IS) bit specifies the size of the index associated with quick object field accesses:
0
Quick object field indices are 8 bits.
1
Quick object field indices are 16 bits.
[26]
SP
The
Static Pointer
(SP) bit controls how the Jazelle hardware treats static references:
0
Static references are treated as handles.
1
Static references are treated as pointers.
[25:1]
-
UNK/SBZP.
[0]
JE
The
Jazelle Enable
(JE) bit controls whether the Jazelle hardware is enabled, or is disabled:
0
The Jazelle hardware is disabled:
•
BXJ
instructions behave like
BX
instructions
•
setting the J bit in the CPSR generates a Jazelle-Disabled Jazelle exception.
1
The Jazelle hardware is enabled:
•
BXJ
instructions enter Jazelle state
•
setting the J bit in the CPSR enters Jazelle state.
Table 5-4 JMCR bit assignments (continued)
Bits
Name
Function
31
22 21
17 16
12 11
8 7
4 3
0
UNK/SBZP
BSH
sADO
ARO
STO
ODO