Message-Id: <199906211407.QAA20050@deimos.worldonline.nl> From: "Bart Alewijnse" To: "Eli Zaretskii" Cc: Subject: Re: Screen copy Date: Mon, 21 Jun 1999 16:05:29 +0200 X-MSMail-Priority: Normal X-Priority: 3 X-Mailer: Microsoft Internet Mail 4.70.1155 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_01BEBBFF.E23DAD20" Content-Transfer-Encoding: 7bit Reply-To: djgpp AT delorie DOT com This is a multi-part message in MIME format. ------=_NextPart_000_01BEBBFF.E23DAD20 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit > On 20 Jun 1999, Bart Alewijnse wrote: > > > How do you copy a double buffer to the screen the fastest? > > If the buffer is contiguous, then use library function `dosmemput' when wouln't it be? Are you implying unchained mode? > (it's documented in the library reference). It already uses the > fastest assembly instructions possible. Including the move-the-aligned-stuff-and-stick-on-the-odds-and-ends thing? I suppose so huh... > > Are there any other ways to do this? What's a fast one/the fastest? > > I suppose that for the LFB it'd just be memcpy > > `dosmemput' uses essentially the same code as `memcpy', except that it > ``wastes'' a single instruction to load _dos_ds into a segment > register before commencing the transfer. Which has a near-zilch effect since that's one or so clock when moving k's of data per frame... Alright then... > If you are really interested in knowing the innards of library > functions, I suggest to download djlsr202.zip and study their > sources. Will do.. And thanks. -Bart ------=_NextPart_000_01BEBBFF.E23DAD20 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable

> On 20 Jun 1999, Bart Alewijnse = wrote:
>
> > How do you copy a double buffer to the = screen the fastest?
>
> If the buffer is contiguous, then = use library function `dosmemput'
when wouln't it be? Are you implying = unchained mode?

> (it's documented in the library reference). =  It already uses the
> fastest assembly instructions = possible.
Including the = move-the-aligned-stuff-and-stick-on-the-odds-and-ends
thing? I = suppose so huh...

> > Are there any other ways to do this? = What's a fast one/the fastest?
> > I suppose that for the LFB = it'd just be memcpy
>
> `dosmemput' uses essentially the = same code as `memcpy', except that it
> ``wastes'' a single = instruction to load _dos_ds into a segment
> register before = commencing the transfer.
Which has a near-zilch effect since that's = one or so clock when
moving k's of data per frame... Alright = then...

> If you are really interested in knowing the innards = of library
> functions, I suggest to download djlsr202.zip and = study their
> sources.
Will do..

And = thanks.

-Bart

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