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Raven PCI Host Bridge & Multi-Processor Interrupt Controller Chip
2
highest priority source. Once an interrupt is acknowledged, only sources
of higher priority will be allowed to interrupt the processor until the EOI
command is received. This register should always be written with a value
of zero which is the nonspecific EOI command.
Interrupt Acknowledge Register
Upon receipt of an interrupt signal, the processor may read this register to
retrieve the vector of the interrupt source which caused the interrupt.
8259 Mode
The 8259 mode bits control the use of an external 8259 pair for PC-AT
compatibility. Following a reset, this mode is set for pass-through, which
essentially disables the advanced controller and passes an 8259 input on
external interrupt source 0 directly through to processor zero. During
interrupt controller initialization this channel should be programmed for
mixed mode in order to take advantage of the interrupt delivery modes.
Current Task Priority Level
Each processor has a separate Current Task Priority Level register. The
system software uses this register to indicate the relative priority of the task
running on the corresponding processor. The interrupt controller will not
deliver an interrupt to a processor unless it has a priority level which is
greater than the current task priority level of that processor. This value is
also used in determining the destination for interrupts which are delivered
using the distributed deliver mode.
Architectural Notes
The hardware and software overhead required to update the task priority
register synchronously with instruction execution may far outweigh the
anticipated benefits of the task priority register. To minimize this
overhead, the interrupt controller architecture should allow the task
priority register to be updated asynchronously with respect to instruction
execution. Lower priority interrupts may continue to occur for an
indeterminate number of cycles after the processor has updated the task
priority register. If this is not acceptable, the interrupt controller
Содержание MVME2700 Series
Страница 1: ...MVME2600 2700 Series Single Board Computer Programmer s Reference Guide V2600A PG2 ...
Страница 13: ...xiv ...
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Страница 67: ...1 50 Board Description and Memory Maps 1 ...
Страница 70: ...Introduction 2 3 2 Four 31 bit tick timers Two 64 bit general purpose registers for cross processor messaging ...
Страница 151: ...2 84 Raven PCI Host Bridge Multi Processor Interrupt Controller Chip 2 ...
Страница 215: ...3 64 Falcon ECC Memory Controller Chip Set 3 ...
Страница 277: ...Glossary GL 14 G L O S S A R Y ...