Intel AT80604004881AA User Manual
Features
174
Intel® Xeon® Processor 7500 Datasheet, Volume 1
7.5.10
Checksums
The PIROM includes multiple checksums.
includes the checksum values for
each section defined in the 128-byte ROM.
Checksums are automatically calculated and programmed by Intel. The first step in
calculating the checksum is to add each byte from the field to the next subsequent
byte. This result is then negated to provide the checksum.
calculating the checksum is to add each byte from the field to the next subsequent
byte. This result is then negated to provide the checksum.
Example: For a byte string of AA445Ch, the resulting checksum will be B6h.
AA = 10101010
44 = 01000100
5C = 0101100
AA + 44 + 5C = 01001010
Negate the sum: 10110101 +1 = 101101 (B6h)
§
Table 7-5.
128-Byte ROM Checksum Values
Section
Checksum Address
Header
0Dh
Processor Data
1Ah
Processor Core Data
29h
Processor Uncore Data
4Bh
Package Data
53h
Part Number Data
65h
Feature Data
76h
Other Data
7Fh