delorie.com/archives/browse.cgi   search  
Mail Archives: djgpp/2000/01/27/14:54:03

From: Damian Yerrick <MYNAMEISd_yerrick AT hotmail DOT comNO2CANNEDHAM>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: DMA access
Organization: Pin Eight Software http://pineight.8m.com/
Message-ID: <ds119sgs9hajic2r9177elulqk2pc817p5@4ax.com>
References: <001301bf68c7$fe83e2e0$43fa4dc6 AT julianro>
X-Newsreader: Forte Agent 1.7/32.534
MIME-Version: 1.0
Lines: 25
X-Trace: /Kw5eD8h5hy1afXRs7yC0IH8ebeN6ta0DDOHXPmem3sqYNslsobqC9Z9Hn9HbkeAdt8ZxY54OR3Y!wjvWONwqCyCwbxFGjieF/oQtRQuM6dWV+pJLhydf50x2pskPU4UFI3GkPwjhln2YgJwTD+zsDw==
X-Complaints-To: abuse AT gte DOT net
X-Abuse-Info: Please be sure to forward a copy of ALL headers
X-Abuse-Info: Otherwise we will be unable to process your complaint properly
NNTP-Posting-Date: Thu, 27 Jan 2000 18:05:53 GMT
Distribution: world
Date: Thu, 27 Jan 2000 18:05:53 GMT
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

On Thu, 27 Jan 2000 08:10:36 -0500, "Julian Rolon"
<jrolon AT alpha DOT telecom-co DOT net> wrote:

>faq states two methods for correct DMA accessig, one of these is
>allocate a buffer in conventional memory with DPMI function
>allocate_dos_memory but this function return a real mode segment
>between 0000 and FFFF, How can i guarantee that segment returned
>falls into Conventional memory??

Short answer: Don't worry.

Longer answer:
Real mode memory is 0x00000000-0x000fffff (1024 KB).
Conventional memory is 0x00000000-0x0009ffff (640 KB).
Upper memory blocks are any space in 0x000a0000-0x000fffff (384 KB)
that is not used by adapter RAM or ROM.
allocate_dos_memory will allocate a conventional memory block and then
return the real mode segment that corresponds to the base of said
block.

-- 
Damian Yerrick  http://yerricde.tripod.com/
Comment on story ideas: http://home1.gte.net/frodo/quickjot.html
AOL is sucks! Find out why: http://anti-aol.org/faqs/aas/
View full sig: http://www.rose-hulman.edu/~yerricde/sig.html

- Raw text -


  webmaster     delorie software   privacy  
  Copyright © 2019   by DJ Delorie     Updated Jul 2019