| August 1998 |
The Segment Descriptor Cache |
The segment descriptor cache is the
heart of memory management, and the key to unlocking real mode. In
this article, I discuss the contents and usage of this undocumented
entity which is the key to unreal mode and more efficient debugging. |
| May 1998 |
The Pentium F00F Bug |
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. |
| May 1998 |
VME: Coming Out of the Cold |
In this article, Robert
finishes his discussion of Virtual Mode Extensions. Robert demonstrates
that Intel left enough information to aid in reverse-engineering,
in spite of attempting to remove vital engineering details of VME.
Many of the known Caveats of VME are discussed. Finally, the VME-related
instruction algorithms are disclosed for the first time in a public
document. |
| March 1998 |
Benchmarks: Fact Fiction or Fantasy? |
Can you really trust published
benchmarks? By making a 166-MHz Pentium computer seem to outperform
a 300-MHz Pentium II system, Robert shows why healthy skepticism is
a useful trait. Brian Butler then presents a sample database benchmark.
Additional resources include BENCHMK.ZIP (source code). |
| March 1998 |
Details and Caveats of Intel's Virtual Mode
Extensions (VME) |
In this article, Robert
continues his discussion of VME by uncovering the inner workings of
Intel's Virtual Mode Extensions. |
| January 1998 |
The Pentium's Enhanced v86 Mode |
In this article, Robert
starts his three-part discussion of Intel's Enhancements to v86 mode.
Robert begins his discussion with a behind-the-scenes look at the
first Ev86 article disclosure in November, 1995. Following the spy
thriller, Robert begins his discussion of v86 mode enhancements on
the Pentium Processor. |
| November 1997 |
ICE Mode and the Pentium Processor
- and -
The Creation of Appendix H |
Robert Continues his examination
of in-circuit emulation and the Pentium by looking at the Pentium's
ICE Mode. |
| September 1997 |
In-Circuit Emulation: How the Microprocessor
Evolved Over Time |
In this article, Robert
continues his discussion of In-Circuit Emulation by discussing the
changes taking place inside of the microprocessor. |
| August 1997 |
Inside the Pentium II Math Bug
- and -
A behind-the-scenes Chronology
of the Dan-0411 Bug |
Two days before Intel's
biggest processor announcement in years, a math bug in the Pentium
Pro and Pentium II came to light. Robert takes you inside the Dan-0411
"flag erratum," and tells how the story unfolded. |
| July 1997 |
In-Circuit Emulation
A powerful hardware tool for software debugging |
Robert discusses the basics
of in-circuit emulation, describing how it has become his primary
software debugging tool. |
| May 1997 |
The Caveats of System Management Mode |
In this issue, Robert discusses
the many caveats of SMM, and gives pointers to make your SMM development
easier. Later in the article, Robert demonstrates how it's possible
to violate the priviledge level mechanism of the Pentium Processor
by modifying values in the SMM State Save Map. |
| March 1997 |
The Secrets of System Management Mode |
In this issue, Robert discusses
the secrets of the state save map, the AutoHALT feature, and I/O Restart
features of Intel's System Management Mode. |
| January 1997 |
Intel's System Management Mode |
Robert launches an examination
of the Intel System Management Mode (SMM), comparing the SMM's RSM
instruction to the ICE mode's undocumented LOADALL instruction. |
|
November 1996
|
CPUID Algorithm Wars -- Part II
|
Robert presents a processor-detection
algorithm that can obtain processor stepping information on processors
thatdon't support the CPUID instruction. |
|
September 1996
|
Detecting Intel Processors: Knowing the generation
of a system CPU
|
How does your program know
which Intel processor is the current system CPU? Robert looks at the
options, including Intel's PUSHF/POPF technique. |
|
July 1996
|
Paging Extensions for the Pentium Pro Processor
|
The Pentium Pro's Physical
Address Extensions (PAE) let the processor address up to 64 GB of
physical memory (36-bit address bus), and access page sizes of 2 MB. |
|
May 1996
|
Understanding Pentium's 4 MB Page Size Extensions
|
Four-MB paging lets the
operating system access very large data structures. However, receiving
documentation for this feature required signing a hefty NDA. Did you
know that this feature was documented all along, if you knew where
to look, and no NDA required. |