[ scummvm-Patches-1705747 ] Speedups for plotYUV and related functions

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Patches item #1705747, was opened at 2007-04-23 10:21
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Robin Watts (robinwatts)
Assigned to: Nobody/Anonymous (nobody)
Summary: Speedups for plotYUV and related functions

Initial Comment:
This patch accelerates the plotYUV1x, plotYUV2x and plotYUV3x functions used for the MPEG playback on all platforms.

The algorithm is fundamentally unchanged, just various additions are moved out from the inner loop, and various additions removed. Finally the loops are reversed to count down towards zero (as on most architectures testing against 0 is cheap/free).

Specifically this patch has been tested with Broken Sword 1 on WinCE, and found to make a significant improvement in speed.

There is no rocket science here - the algorithm hasn't changed at all - it's just an optimised coding.


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You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=418822&aid=1705747&group_id=37116