Compaq EV68A 5.3.4 Dstream TB Invalidate A ll Process (ASM=0) Register DTB_IAP, 5.3.5 Dstream TB Invalidate All Register DTB_IA, 5.3.6 Dstream TB Invalidate Single Registers 0 and 1 DTB_IS0,1,

21264/EV68A Hardware Reference Manual Internal Processor Registers 5–27
Mbox IPRs
5.3.4 Dstream TB Invalidate A ll Process (ASM=0) Register – DTB_IAP
The Dstream translation buffer invalidate all process (ASM=0) register (DTB_IAP) is a
write-onlypseudo register. Write transactions to this register invalidateall DTB entries
in whichthe address space match (ASM) bit is clear.
5.3.5 Dstream TB Invalidate All Register – DTB_IA
The Dstream translationbuffer invalidate all register (DTB_IA) is a write-only pseudo
register.Write transactions to this register invalidate allDTB entriesand reset the DTB
not-last-usedpointer to its initial state.
5.3.6 Dstream TB Invalidate Single Registers 0 and 1– DTB_IS0,1
The Dstreamtranslation buffer invalidate single registers (DTB_IS0 and DTB_IS1) are
write-onlypseudo registers through which software may invalidate a single entry in the
DTB arrays.Writing a virtual page number to one of these registers invalidatesany
DTB entry in the correspondingm emorypipeline which meets one ofthe following cri-
teria:
•The DTB entry’svirtual page number matches DTB_IS[47:13] and its ASN field
matchesDTB _ASN[63:56].
•The DTB entry’svirtual page number matches DTB_IS[47:13] and its ASM bit is
set.
Figure 5–29shows the Dstream translation buffer invalidate single registers.
Figure 5–29 Dstrea mT ranslation BufferI nvalidate Single Registers
ALT_MODE[1:0] [1:0] WO Alt_Mode:
ALT_MODE[1:0] Mode
00 Kernel
01 Executive
10 Supervisor
11 User
Table 5–17 DTB Alternate Proce ssorM odeRe gister Fields Description (Continued)
Name Extent Type Description
63 4847 1312 0
VA[47:13] LK99-0015A