From: "Nick Bull" <nick AT imat DOT demon DOT co DOT uk>
Newsgroups: comp.os.msdos.djgpp
Subject: Calling Software interrupts
Date: Tue, 8 Sep 1998 17:22:30 +0100
Message-ID: <905271833.2795.0.nnrp-05.d4e48d0d@news.demon.co.uk>
NNTP-Posting-Host: imat.demon.co.uk
Lines: 44
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Precedence: bulk

Hi.

I'm trying to write a CDDA -> WAV program using DJGPP.  I've got the basics
working, and now I'm having a bit of hassle.

This is the original code I'm working from :

int ReadLong(DWORD loc, WORD secnum, char far *buf)
{
  struct ReadL {
    struct ReqHdr req;
    BYTE mode;
    void far *address;
    WORD secnum;
    DWORD loc;
    BYTE readmode;
    BYTE skip[2];
  } cmd;

   // snip //

  cmd.address=buf;

  // snip //
}

I think this is where the problem is.  I've removed the "char far *buf" from
the arguments and the "far" from the structure, but I think I'm running into
problems here.  The function should call an interrupt in the MSCDEX driver
that fills buf with data.  All of my other interrupt calls are working OK,
but they don't fill any memory with information.  Can anyone help ?  What am
I doing wrong ?

buf is allocated using a malloc, and I know my calling procedure for the
interrupt works (copies the command block to dos memory and calls using
__dpmi_interrupt).  Help !

Cheers,

Nick.

PS (Sorry for the long and probably not very clear posting)