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Subject: Re: Scrolling thread on iriver

Re: Scrolling thread on iriver

From: Dave Hooper <>
Date: Tue, 14 Jun 2005 21:04:54 +0100

> You could possibly save the shifting, but not the masking.


> It
> might be a bit more efficient, but imho not that much.
> It would also require additional code in lcd_bitmap(), since
> the current implementation always starts reading at bit 0 in
> the source bitmap.

Yep - because that would be necessary for any kind of 'partial blit' routine

> Btw, the jerky scrolling you observed is certainly not a problem
> with the lcd code performance, but rather caused by other
> threads not yielding frequently enough. Rockbox uses a simple
> cooperative round-robin scheduler, and if even one single thread
> holds the cpu for too long, the scrolling can't be smooth.

Totally agree. So the less time the scroll thread itself requires, the
earlier those other threads can take a chance at running, which would
increase the chance of smooth scrolling ;-)

> Regards, Jens

Received on 2005-06-14

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