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35 lines
849 B
35 lines
849 B
/* Compute the sum of the squares of a vector of signed shorts |
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* MMX-assisted version (also used on SSE) |
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* The SSE2 and MMX assist routines both operate on multiples of |
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* 8 words; they differ only in their alignment requirements (8 bytes |
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* for MMX, 16 bytes for SSE2) |
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* Copyright 2004 Phil Karn, KA9Q |
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* May be used under the terms of the GNU Lesser Public License (LGPL) |
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*/ |
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long long sumsq_mmx_assist(signed short *,int); |
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long long sumsq_mmx(signed short *in,int cnt){ |
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long long sum = 0; |
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/* Handle stuff before the next 8-byte boundary */ |
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while(((int)in & 7) != 0 && cnt != 0){ |
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sum += (long)in[0] * in[0]; |
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in++; |
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cnt--; |
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} |
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sum += sumsq_mmx_assist(in,cnt); |
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in += cnt & ~7; |
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cnt &= 7; |
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/* Handle up to 7 words at end */ |
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while(cnt != 0){ |
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sum += (long)in[0] * in[0]; |
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in++; |
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cnt--; |
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} |
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return sum; |
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}
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