
MOTOROLA
Chapter 4. Exceptions
4-13
17
PR
Privilege level
0
The processor can execute both user- and supervisor-level instructions.
1
The processor can only execute user-level instructions.
18
FP
Floating-point available
0
The processor prevents dispatch of floating-point instructions, including floating-point
loads, stores, and moves, default state for the EC603e microprocessor.
1
The processor can execute floating-point instructions, and can take floating-point
enabled exception type program exceptions.
19
ME
Machine check enable
0
Machine check exceptions are disabled.
1
Machine check exceptions are enabled.
20
FE0
Floating-point exception mode 0 (see Table 4-6) (Not supported on the EC603e
microprocessor)
21
SE
Single-step trace enable
0
The processor executes instructions normally.
1
The processor generates a trace exception upon the successful completion of the next
instruction.
22
BE
Branch trace enable
0
The processor executes branch instructions normally.
1
The processor generates a trace exception upon the successful completion of a branch
instruction.
23
FE1
Floating-point exception mode 1 (see Table 4-6) (Not supported on the EC603e
microprocessor)
24
—
Reserved. Full function.
25
IP
Exception prefix. The setting of this bit specifies whether an exception vector offset is
prepended with Fs or 0s. In the following description, nnnnnis the offset of the exception. See
Figure 4-1.
0
Exceptions are vectored to the physical address 0x000n_nnnn
1
Exceptions are vectored to the physical address 0xFFFn_nnnn
26
IR
Instruction address translation
0
Instruction address translation is disabled.
1
Instruction address translation is enabled.
For more information see
Chapter 5, “Memory Management.”
27
DR
Data address translation
0
Data address translation is disabled.
1
Data address translation is enabled.
For more information see
Chapter 5, “Memory Management.”
28–29
—
Reserved. Full function.
30
RI
Recoverable exception (for system reset and machine check exceptions)
0
Exception is not recoverable.
1
Exception is recoverable.
31
LE
Little-endian mode enable
0
The processor runs in big-endian mode.
1
The processor runs in little-endian mode.
Table 4-5. MSR Bit Settings (Continued)
Bit(s)
Name
Description