Appendix E Errata; Mp Floating Pointer Structure - Intel MultiProcessor Specification

The following sections provided here are intended to replace the corresponding sections in the
main body of the specification. The sections provided here are shown in their entirety to provide
context for the changes. Changes contained below are marked with double underlined text which
shows changes relative to the version of the sections that are provided in the main body of the
specification.
4.1

MP Floating Pointer Structure

An MP-compliant system must implement the MP floating pointer structure, which is a variable
length data structure in multiples of 16 bytes. Currently, only one 16-byte data structure is defined.
It must span a minimum of 16 contiguous bytes, beginning on a 16-byte boundary, and it must be
located within the physical address as specified in the previous section. To determine whether the
system conforms to the MP specification, the operating system must search for the MP floating
pointer structure in the order specified in the previous section. Figure 4-2 shows the format of this
structure, and Table 4-1 explains each of the fields.
Version 1.4
31 24 23
MP FEATURE
BYTES 2-5
MP FEATURE
CHECKSUM
BYTE 1
PHYSICAL ADDRESS POINTER
SIGNATURE
_ (5Fh) P (50h)
31 24 23
Figure 4-2. MP Floating Pointer Structure
16 15 8 7
SPEC_REV LENGTH
M (4Dh) _ (5Fh)
16 15 8 7
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