1 files changed, 87 insertions, 0 deletions
diff --git a/neozip/arch/x86/compare256_avx512.c b/neozip/arch/x86/compare256_avx512.c
new file mode 100644
index 0000000000..f3105505cb
--- /dev/null
+++ b/neozip/arch/x86/compare256_avx512.c
@@ -0,0 +1,87 @@
+/* compare256_avx512.c -- AVX512 version of compare256
+ * Copyright (C) 2025 Hans Kristian Rosbach
+ * Based on AVX2 implementation by Mika T. Lindqvist
+ * For conditions of distribution and use, see copyright notice in zlib.h
+ */
+
+#include "zbuild.h"
+#include "zendian.h"
+#include "zmemory.h"
+#include "deflate.h"
+#include "fallback_builtins.h"
+
+#ifdef X86_AVX512
+
+#include <immintrin.h>
+#ifdef _MSC_VER
+#  include <nmmintrin.h>
+#endif
+
+static inline uint32_t compare256_avx512_static(const uint8_t *src0, const uint8_t *src1) {
+    __m512i zmm_src0_4, zmm_src1_4;
+    __m512i zmm_src0_3, zmm_src1_3;
+    __m512i zmm_src0_2, zmm_src1_2;
+    __m512i zmm_src0_1, zmm_src1_1;
+    __m128i xmm_src0_0, xmm_src1_0;
+    uint64_t mask_1, mask_2, mask_3, mask_4;
+    uint32_t mask_0;
+
+    // First do a 16byte round before increasing to 64bytes, this reduces the
+    // penalty for the short matches, and those are usually the most common ones.
+    // This requires us to overlap on the last round, giving a small penalty
+    // on matches of 192+ bytes (Still faster than AVX2 though).
+
+    // 16 bytes
+    xmm_src0_0 = _mm_loadu_si128((__m128i*)src0);
+    xmm_src1_0 = _mm_loadu_si128((__m128i*)src1);
+    mask_0 = (uint32_t)_mm_cmpeq_epu8_mask(xmm_src0_0, xmm_src1_0);
+    if (mask_0 != 0x0000FFFF)
+        return zng_ctz32(~mask_0); /* Invert bits so identical = 0 */
+
+    // 64 bytes
+    zmm_src0_1 = _mm512_loadu_si512((__m512i*)(src0 + 16));
+    zmm_src1_1 = _mm512_loadu_si512((__m512i*)(src1 + 16));
+    mask_1 = _mm512_cmpeq_epu8_mask(zmm_src0_1, zmm_src1_1);
+    if (mask_1 != 0xFFFFFFFFFFFFFFFF)
+        return 16 + zng_ctz64(~mask_1);
+
+    // 64 bytes
+    zmm_src0_2 = _mm512_loadu_si512((__m512i*)(src0 + 80));
+    zmm_src1_2 = _mm512_loadu_si512((__m512i*)(src1 + 80));
+    mask_2 = _mm512_cmpeq_epu8_mask(zmm_src0_2, zmm_src1_2);
+    if (mask_2 != 0xFFFFFFFFFFFFFFFF)
+        return 80 + zng_ctz64(~mask_2);
+
+    // 64 bytes
+    zmm_src0_3 = _mm512_loadu_si512((__m512i*)(src0 + 144));
+    zmm_src1_3 = _mm512_loadu_si512((__m512i*)(src1 + 144));
+    mask_3 = _mm512_cmpeq_epu8_mask(zmm_src0_3, zmm_src1_3);
+    if (mask_3 != 0xFFFFFFFFFFFFFFFF)
+        return 144 + zng_ctz64(~mask_3);
+
+    // 64 bytes (overlaps the previous 16 bytes for fast tail processing)
+    zmm_src0_4 = _mm512_loadu_si512((__m512i*)(src0 + 192));
+    zmm_src1_4 = _mm512_loadu_si512((__m512i*)(src1 + 192));
+    mask_4 = _mm512_cmpeq_epu8_mask(zmm_src0_4, zmm_src1_4);
+    if (mask_4 != 0xFFFFFFFFFFFFFFFF)
+        return 192 + zng_ctz64(~mask_4);
+
+    return 256;
+}
+
+Z_INTERNAL uint32_t compare256_avx512(const uint8_t *src0, const uint8_t *src1) {
+    return compare256_avx512_static(src0, src1);
+}
+
+#define LONGEST_MATCH       longest_match_avx512
+#define COMPARE256          compare256_avx512_static
+
+#include "match_tpl.h"
+
+#define LONGEST_MATCH_SLOW
+#define LONGEST_MATCH       longest_match_slow_avx512
+#define COMPARE256          compare256_avx512_static
+
+#include "match_tpl.h"
+
+#endif