From: pausch AT saafNOSPAM DOT se (Paul Schlyter)
Newsgroups: comp.os.msdos.programmer,comp.os.msdos.djgpp
Subject: Re: adress enabling (Win98)
Date: 28 Aug 2000 19:23:05 +0200
Organization: Svensk Amat|rAstronomisk F|rening (SAAF)
Lines: 47
Message-ID: <8oe75p$nhe$1@merope.saaf.se>
References: <39AA2AD6 DOT A2FFD5B AT siemens DOT at> <enokqs8dk0jah52r8sc22ka2fu48lickep AT 4ax DOT com> <39AA6C2C DOT CF273476 AT siemens DOT at>
NNTP-Posting-Host: merope.saaf.se
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

In article <39AA6C2C DOT CF273476 AT siemens DOT at>,
Martin Alt  <martin DOT alt AT siemens DOT at> wrote:
>> I don't understand what you mean.  Are you using a DOS application to
>> write to a specific address?  It should work just fine in a plain DOS
>> session as well as a Windows '9x session.  Perhaps you could post the
>> relevant portion of code, along with a better description of what you
>> are doing and what the exact result is?
>
> I didn't want to boring with long code, but it looks like:
> 
> -----------
> #define ISAADDR 0xd800
> 
> static unsigned portRead = ISAADDR,portWData  = ISAADDR + 1,portWCtr  = ISAADDR +
> 2,portOE = ISAADDR + 3;
> 
> void bos021_wr(unsigned short reg,unsigned short data)
> {
>   outpw(portWData,data);                                /* write data to Data latch
> */
>   outpw(portWCtr,(unsigned short)(0x01<<(reg-1)));      /* write reg to Controll
> latch */
>   outpw(portOE,(unsigned short)0x03);                   /* enable output */
> }
> ------------
> I didn't get an error, but there is also no outbut (chipselect,...).
> With MS-DOS it works well, so it has something to do that I am not
> allowed to write on this adress.
> I reserved to range in BIOS and/or Win98 but it seems that only a
> device driver has access!?!
 
That's most likely the case.  In Protected Mode, applications don't
have unrestricted access to port I/O.  Which is as it should be,
since there would easily be chaos if multiple applications did access
the same hardware device simultaneously.
 
So you'll have to learn how to write a VxD (Virtual Device Driver)
under Win98.  From within a VxD, you *will* have unrestricted access
to the system.  Which of course also means it's easy to crash the
entire system from within a VxD.
 
-- 
----------------------------------------------------------------
Paul Schlyter,  Swedish Amateur Astronomer's Society (SAAF)
Grev Turegatan 40,  S-114 38 Stockholm,  SWEDEN
e-mail:  pausch at saaf dot se   or    paul.schlyter at ausys dot se
WWW:     http://hotel04.ausys.se/pausch    http://welcome.to/pausch