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26 lines
748 B
C
26 lines
748 B
C
//
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// arch/x86_64/rsp/vsub.h
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//
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// This file is subject to the terms and conditions defined in
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// 'LICENSE', which is part of this source code package.
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//
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#include "common.h"
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static inline __m128i rsp_vsub(__m128i vs, __m128i vt,
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__m128i carry, __m128i *acc_lo) {
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__m128i unsat_diff, sat_diff, overflow, vd;
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// acc_lo uses saturated arithmetic.
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unsat_diff = _mm_sub_epi16(vt, carry);
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sat_diff = _mm_subs_epi16(vt, carry);
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*acc_lo = _mm_sub_epi16(vs, unsat_diff);
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vd = _mm_subs_epi16(vs, sat_diff);
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// VD is the signed diff of the two sources and the carry. Since we
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// have to saturate the diff of all three, we have to be clever.
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overflow = _mm_cmpgt_epi16(sat_diff, unsat_diff);
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return _mm_adds_epi16(vd, overflow);
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}
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