Cbox CSRs and IPRs

5.4.5 Cbox Read Register (IPR) Description

The Cbox read register is read 6 bits at a time. Table 5–26shows the ordering from LSB to MSB.

Table 5–26 Cbox Read IPR Fields Description

Name

Description

 

 

C_SYNDROME_1[7:0]

C_SYNDROME_0[7:0]

C_STAT[4:0]

If CMD is ChxToDirty, then C_SYNDROME_1 is X; otherwise, is syndrome for upper QW in OW of victim that was scrubbed.

If CMD is ChxToDirty, then C_SYNDROME_0 is X; otherwise, is syndrome for lower QW in OW of victim that was scrubbed.

Bits

Error Status

0 0 0 0 0

Either no error, or error on a speculative load, or a Bcache vic-

 

tim read due to a Dcache/Bcache miss

0 0 0 0 1

BC_PERR (Bcache tag parity error)

0 0 0 1 0

DC_PERR (duplicate tag parity error)

0 0 0 1 1

DSTREAM_MEM_ERR

0 0 1 0 0

DSTREAM_BC_ERR

0 0 1 0 1

DSTREAM_DC_ERR

0 0 1 1 X

PROBE_BC_ERR

0 1 0 0 0

Reserved

0 1 0 0 1

Reserved

0 1 0 1 0

Reserved

0 1 0 1 1

ISTREAM_MEM_ERR

0 1 1 0 0

ISTREAM_BC_ERR

0 1 1 0 1

Reserved

0 1 1 1 X

Reserved

1 0 0 1 1

DSTREAM_MEM_DBL1

1 0 1 0 0

DSTREAM_BC_DBL1

1 1 0 1 1

ISTREAM_MEM_DBL1

1 1 1 0 0

ISTREAM_BC_DBL1

 

1 Error status as specified only when Cbox WRITE_ONCE chain bit

 

SKEWED_ FILL_MODE[0] is clear; otherwise, error status is

 

generic DOUBLE_BIT_ERROR (1XXXX).

C_STS[3:0]

If C_STAT equals xxx_MEM_ERR or xxx_BC_ERR, then C_STS contains the

 

status of the block as follows; otherwise, the value of C_STS is X:

 

Bit Value

Status of Block

 

7:4

Reserved

 

3

Parity

 

2

Valid

 

1

Dirty

 

0

Shared

C_ADDR[6:42]

Address of last reported ECC or parity error. If C_STAT value is

 

DSTREAM_DC_ERR, only bits 6:19 are valid. If C_STAT value is

 

DOUBLE_BIT_ERROR and SKEWED_FILL_MODE[0] is set, then C_ADDR

 

is X.

 

 

 

 

Alpha 21264/EV67 Hardware Reference Manual

Internal Processor Registers 5–41

Page 183
Image 183
Compaq 21264, EV67 specifications Cbox CSRs and IPRs Cbox Read Register IPR Description, Cbox Read IPR Fields Description