Compaq EV68A specifications Cbox CSRs and IPRs, 21describes the Dcache status register fields

Models: EV68A

1 356
Download 356 pages 47.63 Kb
Page 174
Image 174

Cbox CSRs and IPRs

Figure 5–34 Dcache Status Register

63

5

4

3

2

1

0

 

 

 

 

 

 

 

SEO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ECC_ERR_LD

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ECC_ERR_ST

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TPERR_P1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TPERR_P0

 

 

 

 

 

 

 

 

 

 

 

 

 

LK99-0042A

 

 

 

 

 

 

 

Table 5–21describes the Dcache status register fields.

Table 5–21 Dcache Status Register Fields Description

 

 

 

 

 

 

 

 

 

 

Name

Extent

Type

Description

 

 

 

 

 

 

 

 

 

 

Reserved

[63:5]

SEO

[4]

W1C

Second error occurred. When set, this bit indicates that a second

 

 

 

 

Dcache store ECC error occurred within 6 cycles of the previous

 

 

 

 

Dcache store ECC error.

ECC_ERR_LD

[3]

W1C

ECC error on load. When set, this bit indicates that a single-bit ECC

 

 

 

 

error occurred while processing a load from the Dcache or any fill.

ECC_ERR_ST

[2]

W1C

ECC error on store. When set, this bit indicates that an ECC error

 

 

 

 

occurred while processing a store.

TPERR_P1

[1]

W1C

Tag parity error — pipe 1. When set, this bit indicates that a Dcache

 

 

 

 

tag probe from pipe 1 resulted in a tag parity error. The error is uncor-

 

 

 

 

rectable and results in a machine check.

TPERR_P0

[0]

W1C

Tag parity error — pipe 0. When set, this bit indicates that a Dcache

 

 

 

 

tag probe from pipe 0 resulted in a tag parity error. The error is uncor-

 

 

 

 

rectable and results in a machine check.

 

 

 

 

 

 

 

 

 

 

5.4 Cbox CSRs and IPRs

This section describes the Cbox CSRs and IPRs.

The Cbox configuration registers are split into three shift register chains:

The hardware allocates 367 bits for the WRITE_ONCE chain, of which the 21264/ EV68A uses 304 bits. During hardware reset (after BiST), 367 bits are always shifted into the WRITE_ONCE chain from the SROM, MSB first, so that the unused bits are shifted out the end of the WRITE_ONCE chain.

A 36-bit WRITE_MANY chain that is loaded using MTPR instructions to the Cbox data register. Six bits of information are shifted into the WRITE_MANY chain dur- ing each write transaction to the Cbox data register.

A 60-bit Cbox ERROR_REG chain that is read by using MFFR instructions from the Cbox data register in combination with MTPR instructions to the Cbox shift register. Each write transaction to the Cbox shift register destructively shifts six bits of information out of the Cbox error register.

5–32Internal Processor Registers

21264/EV68A Hardware Reference Manual

Page 174
Image 174
Compaq EV68A Cbox CSRs and IPRs, 21describes the Dcache status register fields, Dcache Status Register Fields Description