Add ARM special instructions implementation for CRC32.

crc32_arm_simd.c

@@ -0,0 +1,73 @@
+//
+// Created by claunia on 29/9/21.
+//
+
+#if defined(__aarch64__) || defined(_M_ARM64) || defined(__arm__) || defined(_M_ARM)
+
+#include <arm_acle.h>
+
+#include "library.h"
+#include "crc32.h"
+
+TARGET_ARMV8_WITH_CRC uint32_t armv8_crc32_little(uint32_t crc, const unsigned char* buf, uint32_t len)
+{
+    uint32_t c = (uint32_t)~crc;
+
+#if defined(__aarch64__) || defined(_M_ARM64)
+    while(len && ((uintptr_t)buf & 7))
+    {
+        c = __crc32b(c, *buf++);
+        --len;
+    }
+    const uint64_t* buf8 = (const uint64_t*)buf;
+    while(len >= 64)
+    {
+        c = __crc32d(c, *buf8++);
+        c = __crc32d(c, *buf8++);
+        c = __crc32d(c, *buf8++);
+        c = __crc32d(c, *buf8++);
+        c = __crc32d(c, *buf8++);
+        c = __crc32d(c, *buf8++);
+        c = __crc32d(c, *buf8++);
+        c = __crc32d(c, *buf8++);
+        len -= 64;
+    }
+    while(len >= 8)
+    {
+        c = __crc32d(c, *buf8++);
+        len -= 8;
+    }
+
+    buf = (const unsigned char*)buf8;
+#else // AARCH64
+    while(len && ((uintptr_t)buf & 3))
+    {
+        c = __crc32b(c, *buf++);
+        --len;
+    }
+    const uint32_t* buf4 = (const uint32_t*)buf;
+    while(len >= 32)
+    {
+        c = __crc32w(c, *buf4++);
+        c = __crc32w(c, *buf4++);
+        c = __crc32w(c, *buf4++);
+        c = __crc32w(c, *buf4++);
+        c = __crc32w(c, *buf4++);
+        c = __crc32w(c, *buf4++);
+        c = __crc32w(c, *buf4++);
+        c = __crc32w(c, *buf4++);
+        len -= 32;
+    }
+    while(len >= 4)
+    {
+        c = __crc32d(c, *buf4++);
+        len -= 4;
+    }
+
+    buf = (const unsigned char*)buf4;
+#endif
+
+    while(len--) { c = __crc32b(c, *buf++); }
+    return ~c;
+}
+#endif