Compaq AlphaServer ES40, Service Manual

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Registers D-15
Table D–6 ISUM Register Fields
Name Extent Type Description
Reserved [63:39]
EI[5:0] [38:33] RO External Interrupts
SL [32] RO Serial Line Interrupt
CR [31] RO Corrected Read Error Interrupts
PC[1:0] [30:29] RO Performance Counter Interrupts
PC0 when PC[0] is set.
PC1 when PC[1] is set.
SI[15:1] [28:14] RO Software Interrupts
Reserved [13:11]
ASTU, ASTS [10],[9] RO AST Interrupts
For each processor mode, the bit is
set if an associated AST interrupt is
pending. This includes the mode’s
ASTER and ASTRR bits and
whether the processor mode value
held in the IER_CM register is
greater than or equal to the value
for the mode.
Reserved [8:5]
ASTE, ASTK [4],[3] RO AST Interrupts
For each processor mode, the bit is
set if an associated AST interrupt is
pending. This includes the mode’s
ASTER and ASTRR bits and
whether the processor mode value
held in the IER_CM register is
greater than or equal to the value
for the mode.
Reserved [2:0]