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The Unabridged Pentium 4 IA32 Processor Genealogy by Bob Colwell, Tom Shanley

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Cautionary Note

Unless noted otherwise, the representation of all signal states in tables is in logical, not electrical format. As an example, the first row in Table 49-5 on page 1216 shows a 00000b on REQ[4:0]#, indicating a Deferred Reply transaction type. This means that REQ[4:0]# are deasserted (electrical ones) when driven onto REQ[4:0]#.

Table 49-5. Request Types (note: 0 = signal deasserted, 1 = signal asserted)
Packet A (Request)Packet B (Extended Request)Request Type
REQ4#REQ3#REQ2#REQ1#REQ0#REQ4#REQ3#REQ2#REQ1#REQ0#
00000xxxxx

Deferred Reply. Initiated by Response Agent to complete a request received earlier. For more information, see “Pentium® 4 FSB Transaction Deferral” on page 1277.

00001Reserved (ignore).
01000DSZ field. Always 00b (= ...

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