From:	Andrew Crabtree <andrewc AT typhoon DOT rose DOT hp DOT com>
Message-Id:	<199704102214.AA151680495@typhoon.rose.hp.com>
Subject:	Re: Ada, C and interrupts
To:	rchampre AT ada DOT info DOT unlp DOT edu DOT ar (Raul Champredonde)
Date:	Thu, 10 Apr 1997 15:14:55 PDT
Cc:	djgpp AT delorie DOT com
In-Reply-To:	<199704102011.RAA14915@ada.info.unlp.edu.ar>; from "Raul Champredonde" at Apr 10, 97 5:11 pm

>    I programed some functions in `C' to do interrupts and use NETBIOS service routines.
>    My `C' program run well.
Was your C program written originally in DJGPP or a real mode compiler like Turbo C.
It looks like the latter, in chich case you will need to rewrite in DJGPP to use 
with 32 bit ADA.

>    I want to call a NETBIOS functions, previously loaded in the interrupts vector, 
>  
>  *Q1* How do I get the segment to put into the `ES' register? 
>  
>  *Q2* How can I obtein the buffer's address when I alloc memory using `malloc' function 
> since it returned me an address formated in 20 bits (lineal address) and I need 
> an adress formated like this: segment:offset (32 bits). NETBIOS functions 
> requests ES and BX to be setted.

20 bit addresses only in real mode.  Assuming you port your C code to DJGPP then use
dpmi_allocate_dos_memory and __dpmi_int and dosmemput dosmemget.
  This is probably easiest.  The faq does a good
job of explaining this, but if you are still confused send private email and I wil give you
code which does just what you are asking.

>  *Q3* How can I run ada95 in real mode?. Exist any way to run ada95 in non protected mode?

No idea.  If its part of the 32 bit gnu stuff I doubt its possible,

>  **1st. A** :  Use `int86x', then just put the address of your buffer into the register 

Don't do this.  NetBIOS is not one of the special functions.

>  **2nd. A** :  Call `__dpmi_int,' and then put into that register pair an address 
>  of some buffer in *conventional* memory (in the first 1 MByte).The buffer's size 
>  that I need is 64 bytes only.
Nope.  If you just malloced the memory in DJGPP the it doesn't exist in conventional memory.
Thats what the allocate_dos_mem is for.

>  **3rd. A** :  I found a method for transform lineal address to segment-offset address:
>    OFFSET  = (LINEAL_ADDRESS)&000Fh
>    SEGMENT = (shift_right(LINEAL_ADDRSS,4))&FFFFh

Since you used a 32 bit offset into your selector, and not a 20 bit linear this won't work (would
in Turbo C though I think).

>  **4th. A** :  Use the transfer buffer. That buffer is used for all DOS/BIOS 
> services supported by DJGPP, and it resides in conventional memory.  

This could work but I would use your next choice.

>  **5th. A** :  Allocate my own buffer in conventional memory with a call to the
> `__dpmi_allocate_dos_memory' library function. It returns me the segment of
> the allocated block (the offset is zero).  
> 
>   * OK, I've the offset and the segment but when I intended write into the buffer 
> I get "Segmentation Violation and "General Protection Fault".  

Are you using dosmemput to move data into your conventional mem buffer?  Try that.


HTH 

Andrew

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