X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=shared%2Fmemcpy_interleaved.cpp;h=dd7a59656608098ed451998838fcb7a713c5a6af;hb=d92973cb0206e84529011bc8edd644e1a25374bd;hp=2de1ecec3b725498ebc6d92d298e33b332723bd3;hpb=ee6ece72bc12e5527e114e0e1973f0c0b2dc2138;p=nageru

diff --git a/shared/memcpy_interleaved.cpp b/shared/memcpy_interleaved.cpp
index 2de1ece..dd7a596 100644
--- a/shared/memcpy_interleaved.cpp
+++ b/shared/memcpy_interleaved.cpp
@@ -24,8 +24,22 @@ void memcpy_interleaved_slow(uint8_t *dest1, uint8_t *dest2, const uint8_t *src,
 	}
 }
 
+void memcpy_interleaved_word_slow(uint16_t *dest1, uint16_t *dest2, const uint16_t *src, size_t n)
+{
+	assert(n % 2 == 0);
+	uint16_t *dptr1 = dest1;
+	uint16_t *dptr2 = dest2;
+
+	for (size_t i = 0; i < n; i += 2) {
+		*dptr1++ = *src++;
+		*dptr2++ = *src++;
+	}
+}
+
 #if HAS_MULTIVERSIONING
 
+// uint8_t version.
+
 __attribute__((target("default")))
 size_t memcpy_interleaved_fastpath_core(uint8_t *dest1, uint8_t *dest2, const uint8_t *src, const uint8_t *limit);
 
@@ -112,6 +126,100 @@ size_t memcpy_interleaved_fastpath(uint8_t *dest1, uint8_t *dest2, const uint8_t
 	return consumed + memcpy_interleaved_fastpath_core(dest1, dest2, src, limit);
 }
 
+// uint16_t version.
+
+__attribute__((target("default")))
+size_t memcpy_interleaved_word_fastpath_core(uint16_t *dest1, uint16_t *dest2, const uint16_t *src, const uint16_t *limit);
+
+__attribute__((target("avx2")))
+size_t memcpy_interleaved_word_fastpath_core(uint16_t *dest1, uint16_t *dest2, const uint16_t *src, const uint16_t *limit);
+
+__attribute__((target("default")))
+size_t memcpy_interleaved_word_fastpath_core(uint16_t *dest1, uint16_t *dest2, const uint16_t *src, const uint16_t *limit)
+{
+	// No fast path supported unless we have AVX2.
+	return 0;
+}
+
+__attribute__((target("avx2")))
+size_t memcpy_interleaved_word_fastpath_core(uint16_t *dest1, uint16_t *dest2, const uint16_t *src, const uint16_t *limit)
+{
+	size_t consumed = 0;
+	const __m256i *__restrict in = (const __m256i *)src;
+	__m256i *__restrict out1 = (__m256i *)dest1;
+	__m256i *__restrict out2 = (__m256i *)dest2;
+
+	__m256i shuffle_cw = _mm256_set_epi8(
+		15, 14, 11, 10, 7, 6, 3, 2, 13, 12, 9, 8, 5, 4, 1, 0,
+		15, 14, 11, 10, 7, 6, 3, 2, 13, 12, 9, 8, 5, 4, 1, 0);
+	while (in < (const __m256i *)limit) {
+		// Note: Each element in these comments is 16 bits long (lanes are 2x128 bits).
+		__m256i data1 = _mm256_stream_load_si256(in);         // AaBbCcDd EeFfGgHh
+		__m256i data2 = _mm256_stream_load_si256(in + 1);     // IiJjKkLl MmNnOoPp
+
+		data1 = _mm256_shuffle_epi8(data1, shuffle_cw);       // ABCDabcd EFGHefgh
+		data2 = _mm256_shuffle_epi8(data2, shuffle_cw);       // IJKLijkl MNOPmnop
+
+		data1 = _mm256_permute4x64_epi64(data1, 0b11011000);  // ABCDEFGH abcdefgh
+		data2 = _mm256_permute4x64_epi64(data2, 0b11011000);  // IJKLMNOP ijklmnop
+
+		__m256i lo = _mm256_permute2x128_si256(data1, data2, 0b00100000);
+		__m256i hi = _mm256_permute2x128_si256(data1, data2, 0b00110001);
+
+		_mm256_storeu_si256(out1, lo);
+		_mm256_storeu_si256(out2, hi);
+
+		in += 2;
+		++out1;
+		++out2;
+		consumed += 32;
+	}
+
+	return consumed;
+}
+
+// Returns the number of bytes consumed.
+size_t memcpy_interleaved_word_fastpath(uint16_t *dest1, uint16_t *dest2, const uint16_t *src, size_t n)
+{
+	// We assume this to generally be the case, but just to be sure,
+	// drop down to the slow path.
+	if (intptr_t(dest1) % 2 != 0 || intptr_t(dest2) % 2 != 0 || intptr_t(src) % 2 != 0) {
+		return 0;
+	}
+
+	const uint16_t *limit = src + n;
+	size_t consumed = 0;
+
+	// Align end to 32 bytes.
+	limit = (const uint16_t *)(intptr_t(limit) & ~31);
+
+	if (src >= limit) {
+		return 0;
+	}
+
+	// Process [0,15] words, such that start gets aligned to 32 bytes (16 words).
+	const uint16_t *aligned_src = (const uint16_t *)(intptr_t(src + 31) & ~31);
+	if (aligned_src != src) {
+		size_t n2 = aligned_src - src;
+		memcpy_interleaved_word_slow(dest1, dest2, src, n2);
+		dest1 += n2 / 2;
+		dest2 += n2 / 2;
+		if (n2 % 2) {
+			swap(dest1, dest2);
+		}
+		src = aligned_src;
+		consumed += n2;
+	}
+
+	// Make the length a multiple of 32 words (64 bytes).
+	if (((limit - src) % 32) != 0) {
+		limit -= 16;
+	}
+	assert(((limit - src) % 32) == 0);
+
+	return consumed + memcpy_interleaved_word_fastpath_core(dest1, dest2, src, limit);
+}
+
 #endif  // defined(HAS_MULTIVERSIONING)
 
 void memcpy_interleaved(uint8_t *dest1, uint8_t *dest2, const uint8_t *src, size_t n)
@@ -131,3 +239,21 @@ void memcpy_interleaved(uint8_t *dest1, uint8_t *dest2, const uint8_t *src, size
 		memcpy_interleaved_slow(dest1, dest2, src, n);
 	}
 }
+
+void memcpy_interleaved_word(uint16_t *dest1, uint16_t *dest2, const uint16_t *src, size_t n)
+{
+#if HAS_MULTIVERSIONING
+	size_t consumed = memcpy_interleaved_word_fastpath(dest1, dest2, src, n);
+	src += consumed;
+	dest1 += consumed / 2;
+	dest2 += consumed / 2;
+	if (consumed % 2) {
+		swap(dest1, dest2);
+	}
+	n -= consumed;
+#endif
+
+	if (n > 0) {
+		memcpy_interleaved_word_slow(dest1, dest2, src, n);
+	}
+}