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Mail Archives: djgpp/1997/08/08/16:05:42

From: Shawn Hargreaves <Shawn AT talula DOT demon DOT co DOT uk>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Use of ALLEGRO and DJGPP on a 386sx?
Date: Thu, 7 Aug 1997 22:47:42 +0100
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References: <33ea3a69 DOT 684447 AT news DOT demon DOT co DOT uk>
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Gary Cowell (QI'HoS) writes:
>The thing is - I am developing on my (development :))  machine but the
>target machine is a kindly donated 386sx-20 with 2mb of extended
>memory.  The question is this, will the executable run on this
>configuration with a DPMI manager??  

Should do. I haven't been able to test any Allegro programs on a 386 for
over a year, but when I last tried it (I think sometime shortly before
version 2.1) it worked fine.

>The screen is bog standard VGA but im only using 640x480 16 colour 
>anyhow.   

With your own graphics code, I presume? Allegro won't give you anything
better than the mode-X resolutions on a standard VGA card...

>Do i need any special compiler options (other than -i386) to compile 
>this to run on the 386??  

Actually you don't even need -i386. Both -i386 and -i486 generate code
that uses the regular 386 instruction set, and so will run on either
processor. These switches just indicate which one to prioritise for when
optimising the code...

>Does the lack of a math chip matter - does this need emulators/compile 
>options to get round?? I wont be doing any floating point in my code, 
>but I dont know what allegro does internally.

Allegro uses very little floating point math (some in the texture
mapping code, and obviously the float versions of the 3d math routines,
but that is all I can think of). 

To run djgpp floating point programs on a machine without an FPU, you
must either distribute the file emu387.dxe along with your program, or
link with the libemu.a library (add lemu to your gcc link command). See
the FAQ section 11.1 for more info...


--
Shawn Hargreaves - shawn AT talula DOT demon DOT co DOT uk - http://www.talula.demon.co.uk/
Beauty is a French phonetic corruption of a short cloth neck ornament.

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