| 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. |
