Intel SL8K2 Specification Update - Page 50

Errata R R56. The Base of a Null Segment May Be Non-zero on a Processor Supporting Intel® Extended Memory 64 Technology (Intel® EM64T) Problem: In IA-32e mode of the Intel EM64T processor, the base of a null segment may be non-zero. Implication: Due to this erratum, Intel EM64T enabled systems may encounter unexpected behavior when accessing memory using the null selector. Workaround: It is possible for the BIOS to contain a workaround for this erratum. Status: For the steppings affected, see the Summary Tables of Changes. R57. Upper 32 Bits of FS/GS with Null Base May Not Get Cleared in Virtual-8086 Mode on Processors with Intel® Extended Memory 64 Technology (Intel® EM64T) Enabled Problem: For processors with Intel EM64T enabled, the upper 32 bits of the FS and GS data segment registers corresponding to a null base may not get cleared when segments are loaded in Virtual8086 mode. Implication: This erratum may cause incorrect data to be loaded or stored to memory if FS/GS is not initialized before use in 64-bit mode. Intel has not observed this erratum with any commercially available software. Workaround: None identified. Status: For the steppings affected, see the Summary Tables of Changes. R58. Processor May Fault When the Upper 8 Bytes of Segment Selector Is Loaded from a Far Jump through a Call Gate via the Local Descriptor Table Problem: In IA-32e mode of the Intel EM64T processor, control transfers through a call gate via the Local Descriptor Table (LDT) that uses a 16-byte descriptor, the upper 8-byte access may wrap and access an incorrect descriptor in the LDT. This only occurs on an LDT with a LIMIT>0x10008 with a 16-byte descriptor that has a selector of 0xFFFC. Implication: In the event this erratum occurs, the upper 8-byte access may wrap and access an incorrect descriptor within the LDT, potentially resulting in a fault or system hang. Intel has not observed this erratum with any commercially available software. Workaround: None identified. Status: For the steppings affected, see the Summary Tables of Changes. 50 Intel® Pentium® 4 Processor on 90 nm Process Specification Update