From:	Bill Currie <bcurrie AT tssc DOT co DOT nz>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: (new question) problem with memory allocation
Date:	Fri, 09 Jan 1998 16:18:37 +1300
Organization:	Telecommunication Systems Support Centre
Lines:	25
Message-ID:	<34B5970D.148A@tssc.co.nz>
References:	<199801090150 DOT RAA16234 AT adit DOT ap DOT net> <34B58A15 DOT B86CC43B AT xmission DOT com>
NNTP-Posting-Host:	node106.tssc.co.nz
Mime-Version:	1.0
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

David Eberhard wrote:
> 
> Thanks for all the help.  It solved my problem, but now I have
> another. Here's the code:
> 
>    video_selector = __dpmi_allocate_ldt_descriptors(1);
>    __dpmi_set_segment_base_address(video_selector, linear_address);
>    //Set limit to around 2 Meg
>    __dpmi_set_segment_limit(video_selector, 2000000UL);
> 
> Here I am setting up a selector so I can access the linear buffer of
> my video card.  I wanted to set the segment limit to around 2 meg, but
> it crashes my program and gives about the same error that I got with
> my last problem. It crashes when I try to write to video memory using
> the selector I made above.  If I trim down 2000000 to 200000, then my
> program works fine.  Anyone know why?

Yup, DPMI is failing your set limit call.  Segments over 1M in lengt
must be a multiple of 4k.  This means you must use a segment limit of
2002944 (unless you want to go the other way).  Anyway, wouldn't you
want to go to 2097152 (2M exactly)?

Bill
-- 
Leave others their otherness

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