Compaq 21264 - Manual (Page 154)

5–12 Internal Processor Registers Alpha 21264/EV67 Hardware Reference Manual
Ibox IPRs
Table 5–7 describes the interrupt summary register fields.
5.2.12 Hardware Interrupt Clear Register – HW_INT_CLR
The hardware interrupt clear register (HW_INT_CLR) is a write-only register used to
clear edge-sensitive interrupt requests. See Section D.31 for more information about the
PALcode restriction concerning this register. Figure 5–19 shows the hardware interrupt
clear register.
Figure 5–19 Hardware Interrupt Clear Register
Table 5–7 Interrupt Summary Register Fields Description
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] — —
63 29 28 27 26 25 33 32 31 30 0
SL
CR
PC[1:0]
MCHK_D
FBTP
LK99-0025A