Compaq AlphaServer ES40, Service Manual

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D-26 Compaq AlphaServer ES40 Service Guide
D.11 21272-CA Cchip Miscellaneous Register (MISC)
This register is designed so that only writes of 1 affect it. When a 1 is
written to any bit in the register, the programmer does not need to be
concerned with read-modify-write or the status of any other bits in the
register. Once NXM is set, the NXS field is locked. It is unlocked when
software clears the NXM field. The ABW (arbitration won) field is
locked if either ABW bit is set, so the first CPU to write it locks out the
other CPU. Writing a 1 to ACL (arbitration clear) clears both ABW bits
and both ABT (arbitration try) bits and unlocks the ABW field.
Address 801 A000 0040
Access RW
63
0
32
PK1417-99
31 4 3
44 43 40 39
29 28 27 25 24 23 20 19 16 15 12 11 8 7 2 1
reserved
DEVSUP
REV
NXS
000
NXM
00
ACL
ABT
ABW
IPREQ
IPINTR
ITINTR
CPUID