Cbox Read Register - Compaq AlphaServer DS20 Service Manual

3.4

Cbox Read Register

The Cbox Read Register is read 6 bits at a time. Table 3-4 shows the ordering
from LSB to MSB. The register is read only by PALcode and is an element in the
CPU or System Uncorrectable Machine Check Error Logout frame.
Table 3-4 Cbox Read Register
Name Description
C_SYNDROME_1 Syndrome for the upper QW in the OW of victim that was
<7:0> scrubbed.
C_SYNDROME_0 Syndrome for the lower QW in the OW of victim that was
<7:0> scrubbed.
C_STAT<4:0> Bits
00000
00001
00010
00011
00100
00101
0011X
01000
01001
01010
01011
01100
01101
1XXXX
Error status
Either no error, or error on a speculative load, of a
Bcache victim read due to a Dcache/Bcache miss.
BC_PERR (Bcache tag parity error)
DC_PERR (duplicate tag parity error
DSTREAM_MEM_ERR
DSTREAM_BC_ERR
DSTREAM_DC_ERR
PROBE_BC_ERR
Reserved
Reserved
Reserved
ISTREAM_MEM_ERR
ISTREAM_BC_ERR
Reserved
DOUBLE_BIT_ERROR
Error Registers 3-7