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Raven PCI Host Bridge & Multi-Processor Interrupt Controller Chip
2
There is one Task Priority Register per processor. Priority levels from 0
(lowest) to 15 (highest) are supported. Setting the Task Priority Register to
15 masks all interrupts to this processor. Hardware will set the task register
to $F when it is reset or when the Init bit associated with this processor is
written to a one.
Interrupt Acknowledge Registers
On PowerPC-based systems, Interrupt Acknowledge is implemented as a
read request to a memory-mapped Interrupt Acknowledge register.
Reading the Interrupt Acknowledge register returns the interrupt vector
corresponding to the highest priority pending interrupt. Reading this
register also has the following side effects.
❏
The associated bit in the Interrupt Pending Register is cleared.
❏
Reading this register will update the In-Service register.
Reading this register without a pending interrupt will return a value of $FF
hex.
Offset
Processor 0 $200A0
Processor 1 $210A0
Bit
3
1
3
0
2
9
2
8
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
1
9
1
8
1
7
1
6
1
5
1
4
1
3
1
2
1
1
1
0 9 8 7 6 5 4 3 2 1 0
Name
VECTOR
Operation
R
R
R
R
Reset
$00
$00
$00
$FF