Jazelle DBX registers
ARM DDI 0388I
Copyright © 2008-2012 ARM. All rights reserved.
5-5
ID073015
Non-Confidential
Write operation of the JIDR
A write to the JIDR clears the translation table. This has the effect of making all configurable
opcodes executed in software only. See
Jazelle Configurable Opcode Translation Table
5.3.2
Jazelle Operating System Control Register
The JOSCR characteristics are:
Purpose
Enables operating systems to control access to Jazelle Extension
hardware.
Usage constraints
The JOSCR is:
•
only accessible in privileged modes.
•
set to zero after a reset and must be written in privileged modes.
Configurations
Available in all configurations.
Attributes
See the register summary in
.
shows the JOSCR bit assignments.
Figure 5-2 JOSCR bit assignments
shows the JOSCR bit assignments.
31
2 1 0
CV
CD
Reserved, RAZ
Table 5-3 JOSCR bit assignments
Bits
Name
Function
[31:2]
-
Reserved, RAZ.
[1]
CV
Configuration Valid bit.
0 = The Jazelle configuration is invalid. Any attempt to enter Jazelle state when the Jazelle hardware
is enabled:
•
generates a configuration invalid Jazelle exception
•
sets this bit, marking the Jazelle configuration as valid.
1 = The Jazelle configuration is valid. Entering Jazelle state succeeds when the Jazelle hardware is
enabled.
The CV bit is automatically cleared on an exception.
[0]
CD
Configuration Disabled bit.
0 = Jazelle configuration in User mode is enabled:
•
reading the JIDR succeeds
•
reading any other Jazelle configuration register generates an Undefined Instruction exception
•
writing the JOSCR generates an Undefined Instruction exception
•
writing any other Jazelle configuration register succeeds.
1 = Jazelle configuration from User mode is disabled:
•
reading any Jazelle configuration register generates an Undefined Instruction exception
•
writing any Jazelle configuration register generates an Undefined Instruction exception.