
5-16
PowerPC Microprocessor Family: The Bus Interface for 32-Bit Microprocessors
5.4.2 External Interrupt—PowerPC 603 Processor
On the 603, note that in the rare case when the next instruction is not in the completion
queue, the 603 searches elsewhere to provide the appropriate restart instruction address to
SRR0.
5.5 System Management Interrupt Exception
(0x01400)
The system management interrupt, which is implemented on the 603 and 604, but not on
the 601, behaves like an external interrupt except for the signal asserted and the vector
taken.
A system management interrupt is signaled to the processor by the assertion of the SMI
signal. The interrupt may not be recognized if a higher-priority exception occurs
simultaneously or if the MSR[EE] bit is cleared when SMI is asserted. Note that SMI takes
priority over INT if they are recognized simultaneously.
After the assertion of SMI is detected (and provided that MSR[EE] is set), the processor
waits for the next instruction (and any exceptions associated with that instruction) to
complete before taking the system management interrupt. Note that in the rare case when
the next instruction is not in the completion queue, the processor searches elsewhere to
provide the appropriate restart instruction address to SRR0.
The register settings for the system management interrupt exception are the same as those
for the external interrupt, as shown in Table 5-10.
When a system management interrupt is taken, instruction execution for the handler begins
at offset 0x01400 from the physical base address indicated by MSR[IP].
Table 5-10. System Management Interrupt—Register Settings
Register
Setting Description
SRR0
Set to the effective address of the instruction that the processor would have attempted to execute next
if no interrupt conditions were present.
SRR1
0
1–4
5–9
10–15
16–31
Note that depending on the implementation, reserved bits in the MSR may not be copied to SRR1.
Loaded with equivalent bits from the MSR (cleared in the 601)
Cleared
Loaded with equivalent bits from the MSR (cleared in the 601)
Cleared
Loaded with equivalent bits from the MSR
MSR
POW
TGPR
1
0
ILE
EE
0
—
0
PR
FP
ME
FE0
0
0
—
0
SE
BE
FE1
IP
0
0
0
—
IR
DR
RI
LE
0
0
0
Set to value of ILE
1
603e only