IBM PowerPC 405GP User Manual

16
UOF
Data storage interrupt-UO fault
o Excepting instruction did not cause a UO
fault.
1 Excepting instruction did cause a UO
fault.
17:31 Reserved
In general, ESR bits are set to indicate the type of preCise interrupt that occurred; other bits are
cleared. However, the machine
check-instruction (ESR[MCI]) bit behaves differently. Because
instruction-side machine checks can occur without an interrupt being taken (if
MSR[ME].= 0),
ESR[MCI]
can be set even while other ESR-setting interrupts (program, data storage, DTLB-miss)
occurring. Thus, data storage and program interrupts leave
ESR[MCI] unchanged, clear all other ESR
bits, and set the bits associated with any data storage or program interrupts occurred. Enabled
instruction-side machine checks
(MSR[ME] = 1) set ESR[MCI] and clear the data storage and
program interrupt bits.
If a machine check-instruction interrupt occurs but is disabled (MSR[ME] = 0), it sets ESR[MCI] but
leaves the data storage and program interrupt bits alone.
If a machine check-instruction interrupt
occurs while
MSR[ME] = 0, and the instruction upon which the machine check-instruction interrupt
is occurring also is some other kind of ESR-setting instruction (program, data storage, DTLB-miss, or
instruction storage interrupt),
ESR[MCI] is set to indicate that a machine check-instruction interrupt
occurred; the other
ESR bits are set or cleared to indicate the other interrupt. These scenarios are
summarized
in Table 10-5
Table 10-5. ESR Alteration by Various Interrupts
Scenario
ESR
4
:
ESR
s
:
9
,
16 .
Program interrupt without machine check Set to type Cleared
interrupt
Enabled MCI Cleared
Cleared
Disabled MCI,
no others Unchanged
Unchanged
Disabled MCI and program interrupt Set to type Cleared
Table 10-6. ESR Alteration by Various Interrupts
Scenario ECR[MCI]
ESR
4
:
ESR
s
:
9
,16
Program interrupt Unchanged Set to type Cleared
Data storage interrupt Unchanged Cleared Set to Type
Data TLB miss interrupt Unchanged
Cleared Cleared
Machine check-instruction Set to 1 Cleared Cleared
Disabled MCI,
no others Unchanged Unchanged Unchanged
Disabled MCI and program interrupt Unchanged Set to type Cleared
Preliminary Interrupt Controller
Operations
10-33

IBM PowerPC 405GP Specifications

General

Brand	IBM
Model	PowerPC 405GP
Category	Computer Hardware
Language	English