Re: [cc65] C128 functions slow()/fast() for C64

From: Groepaz <groepaz1gmx.net>
Date: 2012-10-21 15:51:36
On Sunday 21 October 2012, you wrote:
> On Sun, 21 Oct 2012 15:22:12 +0200
> 
> "Marc 'BlackJack' Rintsch" <marc@rintsch.de> wrote:
> > Hi *,
> > 
> > Any thoughts about providing `slow()` and `fast()` functions for the
> > C64 target that switch the screen on/off and would set a C128 into 1
> > Mhz/2 Mhz mode?
> > 
> > It is common to do this in computing intensive programs like
> > compression software.  C128 users get some extra speed out of the C64
> > application and on the C64 it doesn't do any harm AFAIK.  Even there
> > you get a small speed gain because the VIC doesn't stall the CPU any
> > more for memory access.
> > 
> > Ciao,
> > 
> > 	Marc 'BlackJack' Rintsch
> 
> Would be nice for Atari target as well. Display-DMA off increase speed
> from 1.2 MHz to 1.8MHz.
> To be precise, display-DMA steals cycles from 6502 that it effictivle
> runs at 1.2MHz instead of 1.8MHz  :)

very similar to the "badlines" of a VIC-II i guess :)

-- 

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<Angela Merkel, CDU>

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Received on Sun Oct 21 15:49:46 2012

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