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Embedded Systems

The Pentium F00F Bug

By Robert R. Collins, May 01, 1998

When x86 processors encounter an invalid instruction, the processor is supposed to generate an invalid opcode exception. If this mechanism fails, however, the program can bring the system down -- and that's what happens with the F00F bug.


The Pentium F00F Bug

The Pentium F00F Bug

By Robert R. Collins

Dr. Dobb's Journal May 1998 

Sequence  Address   Data      Mnemonic                      Timestamp
------------------------------------------------------------------------
T 524285  000000B2----7E--------(-IO-WRITE-)---------------------300 ns
  524286  00000018  ----E14C    ( LOCKED MEM READ )           440 ns
  524287  0000001A  F000----    ( LOCKED MEM READ )            100 ns

Example 1: F00F bug example.

Copyright © 1998, Dr. Dobb's Journal



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