Register Description
R
58 Intel® 82845 MCH for SDR Datasheet
3.5.19 DERRSYN—DRAM Error Syndrome Register (Device 0)
Address Offset: 86h
Default Value: 00h
Access: RO
Size: 8 bits
This register is used to report the ECC syndromes for each quadword of a 32 byte-aligned data
quantity read from the system memory array.
Bit Description
7:0 DRAM ECC Syndrome (DECCSYN). After a system mem ory ECC error, hardware loads this
field with a syndrome that describes the set of bits found to be in error.
Note: Thi s field is locked from the time that it is loaded up to the time when the error flag is
cleared by software. If the first error was a single bit, correctable error, then a subsequent
multiple bit error will overwrite this field. In all other cases, an error that occurs after the
first error and before the error flag has been cleared by software will escape recording.
3.5.20 EAP—Error Address Pointer Register (Device 0)
Address Offset: 8C–8Fh
Default Value: 0000_0000h
Access: RO
Size: 32 bits
This register contains the address of the 32 byte-aligned data unit on which system memory ECC
error(s) was detected.
Bit Descriptions
31:30 Reserved.
29:1 Error Address Pointer (EAP). This field is used to store address bits A[33:5] of the 32-byte-
aligned data unit of system memory of which an error (single bit or multi-bit error) has occurred.
Note: The value of this bit field represents the address of the first s ingle or the first multiple bit
error occurrence after the error flag bits in the ERRSTS register have been cleared by
software. A multiple bit error will overwrite a single bit error. Once the error flag bits are set
as a result of an error, this bit field is locked and does not change as a result of a new error
until the error flag is cleared by software.
0 Reserved.