![Xilinx Virtex-II Pro PPC405 Скачать руководство пользователя страница 196](http://html1.mh-extra.com/html/xilinx/virtex-ii-pro-ppc405/virtex-ii-pro-ppc405_user-manual_3410279196.webp)
504
March 2002 Release
1-800-255-7778
Virtex-II Pro™ Platform FPGA Documentation
Chapter 7:
Exceptions and Interrupts
R
Machine-Check Interrupt (0x0200)
Interrupt Classification
•
Critical—return using the
rfci
instruction.
•
Asynchronous (not guaranteed to be synchronous).
•
Imprecise (not guaranteed to be precise).
Description
A machine-check exception is caused by an error detected on the processor-local bus (PLB).
External devices assert an error signal to the processor when a machine-check error is
recognized. The processor supports two external PLB-error signals, one for instructions
and one for data. This enables the processor to differentiate between machine checks due
to instruction fetching and those caused by data access.
This interrupt is enabled using the machine-check enable bit (ME) in the MSR. When
MSR[ME]
=
1, the processor recognizes exceptions caused by asserting one of the PLB-error
input signals and forces a machine-check interrupt to occur. When MSR[ME]
=
0, the
processor continues to recognize the PLB-error input signals, but an associated machine-
check interrupt does not occur. The exception is not persistent.
All maskable interrupts, including those caused by machine-check exceptions, are
disabled when a machine-check interrupt occurs. The machine-check interrupt handler
should not re-enable MSR[ME] until it has saved SRR2 and SRR3. Saving these registers
avoids potential corruption of the interrupt handler should another machine-check
interrupt occur.
Instruction Machine-Check Interrupt
Instruction machine-check errors are reported to the processor by an external device
during an instruction fetch. However, the exception and subsequent interrupt do not occur
until the processor attempts to
execute
the instruction that caused the error. If the erroneous
instruction fetch results in a cache-line fill, any instruction later executed from the
cacheline can cause the exception to occur. Machine-check exceptions associated with
cached instructions always invalidate the corresponding instruction-cacheline.
ESR[MCI] is set to 1 by all instruction machine-check exceptions. This is true regardless of
whether the machine-check interrupt is enabled or not. If machine-check interrupts are
disabled (MSR[ME]
=
0), software can periodically examine ESR[MCI] to determine if any
instruction machine-check exceptions have occurred. Software should clear ESR[MCI] to 0
before returning from the machine-check interrupt handler to avoid any ambiguity when
handling subsequent machine-check interrupts.
Data Machine-Check Interrupt
Data machine-check errors are reported to the processor by an external device during a
data access. Determining the cause is dependent on the system implementation. Generally
the data machine-check interrupt handler must examine the error-reporting registers
located in the external-PLB devices to determine the exception cause.
Содержание Virtex-II Pro PPC405
Страница 1: ...R Volume 2 a PPC405 User Manual Virtex II Pro Platform FPGA Developer s Kit March 2002 Release...
Страница 14: ...322 www xilinx com March 2002 Release 1 800 255 7778 Virtex II Pro Platform FPGA Documentation Preface R...
Страница 252: ...560 www xilinx com March 2002 Release 1 800 255 7778 Virtex II Pro Platform FPGA Documentation R...
Страница 260: ...568 www xilinx com March 2002 Release 1 800 255 7778 Virtex II Pro Platform FPGA Documentation R...
Страница 562: ...870 www xilinx com March 2002 Release 1 800 255 7778 Virtex II Pro Platform FPGA Documentation R...