Directnt, c't 1/97 S. 312, as , english
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Programs for Windows NT 4.0

directnt.doc   ; This text
directnt.cpp   ; Listing of the driver, compilation needs DDK
directnt.sys   ; compiled Driver
directnt.h     ; Include file which specificates the Interface
directnt.rc    ; Ressource file
cx.cpp         ; Cyrix 6x86 configuration program: source
cx.exe         ; Cyrix 6x86 configuration program: executable german
cxe.exe        ; Cyrix 6x86 configuration program: executable english
showmem.cpp    ; Sample program for the use of Directnt
showmem.exe    ; executable german
showmeme.exe   ; executable english
setup.exe      ; Installer for the driver
setup.cpp      ; Source of the installer
setup.rc       ; Ressource file
inst.bat       ; Loads the driver
stop.bat       ; Unloads then  driver
m.bat          ; "Makefile" for Visual C++ 2.0 for directnt.sys
               ; as batch file (adjust paths!!!)
giveio.sys     ; Direct I/O from Dr. Dobb's 5/96
directio.zip   ; Sources and Readme from  Dr. Dobb's 5/96
               ; availabe in
               ; ftp://ftp.mv.com/pub/ddj/1996/1996.05/directio.zip

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The driver Directnt.sys allows direct access to ports, PCI and the
internal processor registers CR0, MSR and to the memory (physically
addressed, only read access!). All the supported functions of the driver
are listed in the include file directnt.h

CX.exe is an application that communicates with the directnt driver.
You can activate (or deactivate) several features of the cyrix 6x86
processor:

Write Back or Write Through Cache Stragegy

Suspend on Halt (saving a lot of power)

Writegathering and Weak Write Ordering for the framebuffer
accelerating access to the framebuffer.

CPUID-Enable:  can be necessary, if software needs CPUID
(e.g. to detect MMX-Support).

Write-Allocation Strategy

Linear Burst (read only)

Parameter:
-----------

("Parameter: /WB :L1-Cache Write Back,   /WT : Write Through \n");
("           /SP :Suspend on HALT active,/NSP: passive\n");
("           /FF :Fast Framebuffer      ,/NFF: Slow\n");
("           /ID :CPUID on              ,/NID: CPUID off\n");
("           /WA :Write Allocation on   ,/NWA: Write Allocation off\n");
("           /Wait: Console waits for Key \n");


The application Showmem.exe is a sample for peeking into Windows
NT memory.

Showmem xxx yyy
shows the contents of the physical addresses from xxx to yyy.


Installation
-----------------------------------------------------
First of all, you have to install the driver with Setup.exe.
Then you must reboot the system. Now the driver is
automatically ready for use by applications.

Finally you can configure the processor with cx /xxx /yyy /zzz
It's useful to put CX with the parameters wanted into the startup folder.
If you like to see the message window of cx, you can add /wait,
then cx waits for a key stroke.

Stop.bat is a batch file for unloading the driver, with inst.bat you can
load it once more (adjust path!). This is very useful for testing new
driver versions.


Giveio.sys from Dale Roberts (Dr.Dobb's 5/96) can permit accesses to the
whole I/O-Area (even for a DOS-Box). But it is somewhat dangerous, because
usually NT has to survey many I/O-Accesses. You find more information
in the readme file in directio.zip!

Questions, suggestions, criticisms => as@ct.heise.de