Ibox IPRs

Figure 5–22 Ibox Control Register

63

48 47

30 29

24 23 22 21 20 19 18 17 16 15 14 13 12 11 10

9

8

7

6

5

3

2

1

0

SEXT(VPTB[47])

VPTB[47:30]

CHIP_ID[5:0]

BIST_FAIL

TB_MB_EN

MCHK_EN

ST_WAIT_64K

PCT1_EN

PCT0_EN

SINGLE_ISSUE_H

VA_FORM_32

VA_48

SL_RCV

SL_XMIT

HWE

BP_MODE[1:0]

SBE[1:0]

SDE[1:0]

SPE[2:0]

IC_EN[1:0]

SPCE

LK99-0029A

Table 5–11describes the Ibox control register fields.

Table 5–11 Ibox Control Register Fields Description

Name

Extent

Type

Description

 

 

 

 

SEXT(VPTB[47])

[63:48]

RW,0

Sign extended VPTB[47].

VPTB[47:30]

[47:30]

RW,0

Virtual Page Table Base. See Section 5.1.5 for details.

CHIP_ID[5:0]

[29:24]

RO

This is a read-only field that supplies the revision ID number

 

 

 

for the 21264/EV68A part.

 

 

 

21264/EV68A pass 2.1 ID is 0100102.

BIST_FAIL

[23]

RO,0

Indicates the status of BiST (clear = pass, set = fail),

 

 

 

described in Section 11.5.1.

TB_MB_EN

[22]

RW,0

When set, the hardware ensures that the virtual-mode loads

 

 

 

in DTB and ITB fill flows that access the page table and the

 

 

 

subsequent virtual mode load or store that is being retried are

 

 

 

‘ordered’ relative to another processor’s stores. This must be

 

 

 

set for multiprocessor systems in which no MB instruction is

 

 

 

present in the TB fill flow, unless there are other mecha-

 

 

 

nisms present that ensure coherency.

MCHK_EN

[21]

RW,0

Machine check enable — set to enable machine checks.

5–16Internal Processor Registers

21264/EV68A Hardware Reference Manual

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Compaq EV68A specifications 11describes the Ibox control register fields, Ibox Control Register Fields Description