Intel CORE I7-900 DEKSTOP - SPECIFICATION Specification page 65

Errata
AAJ138. FP Data Operand Pointer May Be Incorrectly Calculated After an FP
Access Which Wraps a 4-Gbyte Boundary in Code That Uses 32-Bit
Address Size in 64-bit Mode
The FP (Floating Point) Data Operand Pointer is the effective address of the
Problem:
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 wraps 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 4-Gbyte 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 accesses
are wrapped around a 64-Kbyte boundary.
For the steppings affected, see the Summary Table of Changes.
Status:
AAJ139. IO_SMI Indication in SMRAM State Save Area May Be Lost
The IO_SMI bit (bit 0) in the IO state field at SMRAM offset 7FA4H is set to
Problem:
"1" by the processor to indicate a System Management Interrupt (SMI) is
either taken immediately after a successful I/O instruction or is taken after a
successful iteration of a REP I/O instruction. Due to this erratum, the setting
of the IO_SMI bit may be lost. This may happen under a complex set of
internal conditions with Intel® Hyper-Threading Technology enabled and has
not been observed with commercially available software.
Implication: Due to this erratum, SMI handlers may not be able to identify the occurrence
of I/O SMIs.
Workaround: None identified.
For the steppings affected, see the Summary Table of Changes.
Status:
®
Intel Core™ i7 processor
Specification Update
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