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AMD Athlon™ Processor Model 4 Revision Guide

23614K—October 2003

Preliminary Information

AMD Athlon™ Processor Model 4 

Revision Guide

The purpose of the 

AMD Athlon™ Processor Model 4 Revision Guide 

is to communicate updated product

information on the AMD Athlon™ processor model 4 to designers of computer systems and software
developers. This guide consists of three sections:

Product Errata: 

This section, which starts on page 5, provides a detailed description of product

errata, including potential effects on system operation and suggested workarounds. An erratum is
defined as a deviation from the product’s specification. A product errata may cause the behavior of
the AMD Athlon™ Processor Model 4 to deviate from published specifications.

Revision Determination: 

This section, which starts on page 20, shows the AMD Athlon processor

model 4 identification numbers returned by the CPUID instruction for each revision of the
processor.

Technical and Documentation Support:

 This section, which starts on page 21, provides a listing of

available technical support resources. It also lists corrections, modifications, and clarifications to
listed documents. Please refer to the data sheets listed in this section for product marking
information.

Revision Guide Policy

Occasionally AMD identifies deviations from or changes to the specification of the AMD Athlon
processor model 4. These changes are documented in the 

AMD Athlon™ Processor Model 4 Revision

Guide

 as errata. Descriptions are written to assist system and software designers in using the AMD

Athlon processor model 4 and corrections to AMD’s documentation on the AMD Athlon processor
model 4 are included. This release documents currently characterized product errata, but is not
intended to identify all errata in the processor.

Summary of Contents for Athlon 4

Page 1: ...AMD Athlon Processor Model 4 Revision Guide Publication 23614 Rev K Issue Date October 2003 Preliminary Information...

Page 2: ...ation Except as set forth in AMD s Standard Terms and Conditions of Sale AMD assumes no liability whatsoever and disclaims any express or implied warranty relating to its products including but not li...

Page 3: ...n History Date Rev Description October 2003 K Revised erratum 24 June 2003 J Added erratum 24 December 2002 I Added errata 21 23 July 2002 H Added erratum 20 March 2002 G Added erratum 17 April 2001 F...

Page 4: ...s on page 20 shows the AMD Athlon processor model 4 identification numbers returned by the CPUID instruction for each revision of the processor Technical and Documentation Support This section which s...

Page 5: ...roduct Revision to Errata Errata Numbers and Description Revision Numbers A4 A5 A6 A7 A9 5 MCA Bus Unit Control Register MSR 408H Returns Incorrect Information X X X X X 10 Resistance Value of the ZN...

Page 6: ...the upper 32 bits in EDX Non conformance A read to the Machine Check Architecture MCA Bus Unit Control MSR 408h MC2_CTL returns incorrect information in EDX It returns the information stored in the up...

Page 7: ...t on System The AMD Athlon system bus signal quality for signals driven to the Northbridge may be adversely affected Suggested Workaround All motherboards should have ZN ZP resistors set to approximat...

Page 8: ...strength levels in the driver compensation circuit The compensation circuit attempts to correct the drive strength but if there is not sufficient time to perform this function the system bus cannot op...

Page 9: ...as specified Non conformance Under rare and unlikely conditions the load store unit instruction scheduler and effective address generation unit interact in such a way that deadlock a occurs preventin...

Page 10: ...from a low power state and reconnect to the system bus when the nominal operating frequency is generated with a half frequency multiplier This circuit is rarely observed to glitch when coming out of...

Page 11: ...properly after a microcode patch is loaded Non conformance The processor has the patch RAM BIST function disabled Since BIST is not run on the patch RAM reliable operation of the patch RAM cannot be a...

Page 12: ...ted logical address Non conformance When the logical address designated by the INVLPG instruction is mapped by a 4 Mbyte page mapping and LA 21 is equal to one it is possible that the TLB will still r...

Page 13: ...ification has generated an instruction cache invalidation 2 The processor is fetching the line that is being invalidated 3 The fetch misses in the Level 1 instruction TLB 4 The fetch hits in the Level...

Page 14: ...invalidates the instruction cache line with address A and brings the line into the L1 data cache marking it as modified However the instruction buffer which also contains some bytes from address A is...

Page 15: ...ection exception Non conformance If the RDPMC is executed in real mode with a specific illegal value of ECX 4 then the processor may incorrectly enter the GP fault handler as if it were in 32 bit real...

Page 16: ...conformance When a task gate is used by a CALL or JMP instruction and any debug breakpoint is enabled through the DR7 LE or GE bits the processor may under certain timing scenarios incorrectly use the...

Page 17: ...estart the processor should immediately enter the debug trap handler Non conformance Under this scenario the processor does not enter the debug trap handler but instead returns to the instruction foll...

Page 18: ...y occur infrequently on a prefetch instruction Suggested Workaround Two workarounds are described for this erratum Kernel Workaround The Operating System kernel can work around the erratum by allowing...

Page 19: ...ion per cache line a naturally aligned 64 byte quantity and ensuring one of the following In many cases if a particular target address of a prefetch is known to encounter this errata simply change the...

Page 20: ...n 2 Revision Determination Table 2 shows the AMD Athlon processor model 4 identification number returned by the CPUID instruction for each revision of the processor Table 2 CPUID Values for the Revisi...

Page 21: ...to the data sheets listed in this section for product marking information AMD Athlon Processor Model 4 Data Sheet order 23792 AMD 751 System Controller Data Sheet order 21910 AMD 756 Peripheral Bus C...

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