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Date: Thu, 14 Feb 2002 12:26:48 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
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To: Altaf <aladhani AT charter DOT net>
cc: djgpp AT delorie DOT com
Subject: Re: Need help with FP_SEG and FP_OFF
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On Wed, 13 Feb 2002, Altaf wrote:

> I have just started to port an old 16bit code to DJGPP'c gcc compiler.
> I have a small segment of code which I can not port. I ueses SREGS
> structure.
> 
> Here is an example. If someone can look at it and let me know how to
> translate into DJGPP's. I have been reading FAQ section 17.6 and 18.2
> and more. BUT I am still not being able to solve the mystery of
> register.

Could you please be more specific about what's missing in the FAQ?
There's a working example of code in section 18.2 that should explain
how to write such code.  What is unclear about it that prevented you
from rewriting your code for DJGPP yourself?

I attach below the (untested) DJGPP version of your code.  Can you
tell what parts of the code below need some knowledge that is not in
section 18.2's text and example?

> My problem area is:
> FP_SEG and FP_OFF(). DJGPP does not have these two functions.
> Can I write my own? OR Can I somehow translate them into DJGPP.

As the FAQ tells, you don't need FP_OFF and FP_SEG.

Here's the code; any questions?  I've put comments where your code is
incomplete.  Also, I suggest to read section 18.5 carefully, since
your code seems to pass structures to a real-mode service.

#include <sys/types.h>
#include <sys/movedata.h>
#include <dpmi.h>
#include <go32.h>

int someFn(someStruct *profileptr)
{
  __dpmi_regs r;
  unsigned char *fdata;
  fdata = (char *)profileptr;
  printf("fdata in setprofile: [%s] \n", fdata);
  printf("fdata in setprofile: [%s] \n", fdata);

  r.h.ah = 0x44;
  r.h.al = 0x03; /* could have simply said "r.x.ax = 0x4403;" instead */
  r.x.bx = handle; /* this is undeclared: a possible bug */

  /* You need to pass profile_size, the size of the structure
     someStruct in bytes.  */
  dosmemput (profileptr, profile_size, _tb);
  r.x.ds = _tb >> 4;
  r.x.dx = _tb & 0x0f;
  r.x.cx = SETPROFILE;
  __dpmi_int (0x21, &r);

  /* Error checking missing here.  You should at least look at
     (r.x.flags & 1), the carry flag: if it's set, the call failed.  */

  printf("End of setprofile \n");
}