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/
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References:	<001301bf68c7$fe83e2e0$43fa4dc6 AT julianro>
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NNTP-Posting-Date:	Thu, 27 Jan 2000 18:05:53 GMT
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Date:	Thu, 27 Jan 2000 18:05:53 GMT
To:	djgpp AT delorie DOT com
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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.

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