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Re: vec_mradds -> _mm_maddubs_epi16 ???
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Re: vec_mradds -> _mm_maddubs_epi16 ???




On Nov 15, 2006, at 7:13 AM, John Stiles wrote:

BTW, I think you call an optimized RGB->YUV function via QuickTime.
(Or even more optimized via OpenGL, if you write a pixel shader.)

You can also call vImageMatrixMultiply_<fmt>.

In any case, the answer to your question is that _mm_mulhrs_epi16 + _mm_adds_epi16 is *almost* the same thing as vec_mradds. The double saturation will cause off by one errors for some rare cases near the limits of saturation.

Ian



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References: 
 >vec_mradds -> _mm_maddubs_epi16 ??? (From: Marc Van Olmen <email@hidden>)
 >Re: vec_mradds -> _mm_maddubs_epi16 ??? (From: Paul Russell <email@hidden>)
 >Re: vec_mradds -> _mm_maddubs_epi16 ??? (From: John Stiles <email@hidden>)



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