Intel® Xeon® Processor 5600 Series
43
Specification Update, March 2010
BD88.
FP Data Operand Pointer May Be Incorrectly Calculated After an FP
Access Which Wraps a 64-Kbyte Boundary in 16-bit Code
Problem:
The FP (Floating Point) Data Operand Pointer is the effective address of the operand
associated with the last non-control FP instruction executed by the processor. If an 80-
bit FP access (load or store) occurs in a 16-bit mode other than protected mode (in
which case the access will produce a segment limit violation), the memory access wrap
a 64-Kbyte boundary, and the FP environment is subsequently saved, the value
contained in the FP Data Operand Pointer may be incorrect.
Implication:
Due to this erratum, the FP Data Operand Pointer may be incorrect. Wrapping an 80-bit
FP load around a segment boundary in this way is not a normal programming practice.
Intel has not observed this erratum with any commercially available software.
Workaround:
If the FP Data Operand Pointer is used in an operating system which may run 16-bit FP
code, care must be taken to ensure that no 80-bit FP access are wrapped around a 64-
Kbyte boundary.
Status:
For the steppings affected, see the
BD89.
Spurious PROCHOT# Assertion During Warm Reset May Hang the
Processor
Problem:
The processor may hang if there is a spurious PROCHOT# pin assertion during a warm
reset. The hang may occur even if the minimum hold time specification for PROCHOT#
is not met or voltage regulator based throttling is not enabled.
Implication:
Due to this erratum the processor may hang if there is any spurious assertion of the
PROCHOT# pin during a warm reset.
Workaround:
It is possible of the BIOS to contain a workaround for this erratum, to be used in
conjunction with a BIOS modification.
Status:
