
4-8
MPC603e & EC603e RISC Microprocessors User's Manual
MOTOROLA
Exception priorities are described in detail in “Exception Priorities,” in Chapter 6,
“Exceptions,” in
The Programming Environments Manual
.
Instruction
dispatch/
execution
0
IABR
Instruction address breakpoint exception
1
Program
Program exception due to the following:
Illegal instruction
Privileged instruction
Trap
2
System call
System call exception
3
Floating-point
unavailable
Floating-point unavailable exception due to the following:
603e microprocessor—Floating-point unavailable
exception.
EC603e microprocessor—Execution of a floating-point
instruction.
4
Program
Program exception due to a floating-point enabled exception
5
Alignment
Alignment exception due to the following:
Floating-point not word-aligned (not applicable to the
EC603e microprocessor)
lmw
,
stmw
,
lwarx
, or
stwcx.
not word-aligned
Little-endian access is misaligned
Multiple or string access with little-endian bit set
6
Data access
Data access exception due to a BAT page protection violation
7
Data access
Data access exception due to the following:
eciwx
,
ecowx
,
lwarx
, or
stwcx.
to direct-store segment
(bit 5 of DSISR)
Crossing from memory segment to direct-store segment
(bit 0 of DSISR)
Crossing from direct-store segment to memory segment
Any access to direct-store, SR[T] = 1
eciwx
or
ecowx
with EAR[E] = 0 (bit 11 of DSISR)
8
DTLB miss
Data TLB miss exception due to:
Store miss
Load miss
9
Alignment
Alignment exception due to a
dcbz
to a write-through or
caching-inhibited page
10
Data access
Data access exception due to TLB page protection violation
11
DTLB miss
Data TLB miss exception due to a change bit not set on a store
operation
Post-
instruction
execution
0
Trace
Trace exception due to the following:
MSR[SE] = 1
MSR[BE] = 1 for branches
Table 4-2. Exception Priorities (Continued)
Exception
Category
Priority
Exception
Cause