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IDT MIPS32 4Kc Processor Core
CP0 Registers
79RC32438 User Reference Manual
2 - 75
November 4, 2002
Notes
IEXI
20
Imprecise Error eXception Inhibit controls exceptions
taken due to imprecise error indications. Set when
the processor takes a debug exception or exception
in debug mode. Cleared by execution of the DERET
instruction. Otherwise modifiable by debug mode
software. When IEXI is set then the imprecise error
exceptions from bus error on instruction fetch or data
access, cache error or machine check are inhibited
and deferred until the bit is cleared.
R/W
0
R
19:18
Reserved. Must be written as zero; returns zero on
read.
R
0
Ver
17:15
EJTAG version
R
1
DExcCode
14:10
Indicates the cause of the latest exception in debug
mode. The field is encoded as the ExcCode field in
the Cause register for those normal exceptions that
may occur in debug mode.
Value is undefined after a debug exception.
R
Undefined
R
9
Reserved. Must be written as zero; returns zero on
read.
R
0
SSt
8
Controls if debug single step exception is enabled:
0: No debug single step exception enabled
1: Debug single step exception enabled
R/W
0
R
7:6
Reserved. Must be written as zero; returns zero on
read.
R
0
DINT
5
Indicates that a debug interrupt exception occurred.
Cleared on exception in debug mode.
0: No debug interrupt exception
1: Debug interrupt exception
R/W
Undefined
DIB
4
Indicates that a debug instruction break exception
occurred. Cleared on exception in debug mode.
0: No debug instruction exception
1: Debug instruction exception
R
Undefined
DDBS
3
Indicates that a debug data break exception occurred
on a store. Cleared on exception in debug mode.
0: No debug data exception on a store
1: Debug instruction exception on a store
R
Undefined
DDBL
2
Indicates that a debug data break exception occurred
on a load. Cleared on exception in debug mode.
0: No debug data exception on a load
1: Debug instruction exception on a load
R
Undefined
DBp
1
Indicates that a debug software breakpoint exception
occurred. Cleared on exception in debug mode.
0: No debug software breakpoint exception
1: Debug software breakpoint exception
R
Undefined
DSS
0
Indicates that a debug single step exception
occurred. Cleared on exception in debug mode.
0: No debug single step exception
1: Debug single step exception
R
Undefined
Fields
Description
Read/
Write
Reset
State
Name
Bit(s)
Table 2.50 Debug Register Field Descriptions (Part 2 of 2)