Add 'neozip/' from commit 'c2712b8a345191f6ed79558c089777df94590087'

git-subtree-dir: neozip
git-subtree-mainline: b1e34e861b5d732afe828d58aad2c638135061fd
git-subtree-split: c2712b8a345191f6ed79558c089777df94590087

1 files changed, 49 insertions, 0 deletions

diff --git a/neozip/arch/arm/slide_hash_armv6.c b/neozip/arch/arm/slide_hash_armv6.c
new file mode 100644
index 0000000000..b241e6c5e6
--- /dev/null
+++ b/neozip/arch/arm/slide_hash_armv6.c
@@ -0,0 +1,49 @@
+/* slide_hash_armv6.c -- Optimized hash table shifting for ARMv6 with support for SIMD instructions
+ * Copyright (C) 2023 Cameron Cawley
+ * For conditions of distribution and use, see copyright notice in zlib.h
+ */
+
+#ifdef ARM_SIMD
+
+#include "zbuild.h"
+#include "acle_intrins.h"
+#include "deflate.h"
+
+/* SIMD version of hash_chain rebase */
+static inline void slide_hash_chain(Pos *table, uint32_t entries, uint16_t wsize) {
+    Z_REGISTER uint16x2_t v;
+    uint16x2_t p0, p1, p2, p3;
+    Z_REGISTER size_t n;
+
+    size_t size = entries*sizeof(table[0]);
+    Assert((size % (sizeof(uint16x2_t) * 4) == 0), "hash table size err");
+
+    Assert(sizeof(Pos) == 2, "Wrong Pos size");
+    v = wsize | (wsize << 16);
+
+    n = size / (sizeof(uint16x2_t) * 4);
+    do {
+        p0 = *((const uint16x2_t *)(table));
+        p1 = *((const uint16x2_t *)(table+2));
+        p2 = *((const uint16x2_t *)(table+4));
+        p3 = *((const uint16x2_t *)(table+6));
+        p0 = __uqsub16(p0, v);
+        p1 = __uqsub16(p1, v);
+        p2 = __uqsub16(p2, v);
+        p3 = __uqsub16(p3, v);
+        *((uint16x2_t *)(table)) = p0;
+        *((uint16x2_t *)(table+2)) = p1;
+        *((uint16x2_t *)(table+4)) = p2;
+        *((uint16x2_t *)(table+6)) = p3;
+        table += 8;
+    } while (--n);
+}
+
+Z_INTERNAL void slide_hash_armv6(deflate_state *s) {
+    Assert(s->w_size <= UINT16_MAX, "w_size should fit in uint16_t");
+    uint16_t wsize = (uint16_t)s->w_size;
+
+    slide_hash_chain(s->head, HASH_SIZE, wsize);
+    slide_hash_chain(s->prev, wsize, wsize);
+}
+#endif