From f19f813537c7aea1c20749c914e756b54a9c3cf5 Mon Sep 17 00:00:00 2001
From: Igor Pavlov <87184205+ip7z@users.noreply.github.com>
Date: Mon, 27 Dec 2021 00:00:00 +0000
Subject: '21.07'

---
 C/XzCrc64Opt.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 C/XzCrc64Opt.c

(limited to 'C/XzCrc64Opt.c')

diff --git a/C/XzCrc64Opt.c b/C/XzCrc64Opt.c
new file mode 100644
index 0000000..93a9fff
--- /dev/null
+++ b/C/XzCrc64Opt.c
@@ -0,0 +1,71 @@
+/* XzCrc64Opt.c -- CRC64 calculation
+2021-02-09 : Igor Pavlov : Public domain */
+
+#include "Precomp.h"
+
+#include "CpuArch.h"
+
+#ifndef MY_CPU_BE
+
+#define CRC64_UPDATE_BYTE_2(crc, b) (table[((crc) ^ (b)) & 0xFF] ^ ((crc) >> 8))
+
+UInt64 MY_FAST_CALL XzCrc64UpdateT4(UInt64 v, const void *data, size_t size, const UInt64 *table);
+UInt64 MY_FAST_CALL XzCrc64UpdateT4(UInt64 v, const void *data, size_t size, const UInt64 *table)
+{
+  const Byte *p = (const Byte *)data;
+  for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++)
+    v = CRC64_UPDATE_BYTE_2(v, *p);
+  for (; size >= 4; size -= 4, p += 4)
+  {
+    UInt32 d = (UInt32)v ^ *(const UInt32 *)(const void *)p;
+    v = (v >> 32)
+        ^ (table + 0x300)[((d      ) & 0xFF)]
+        ^ (table + 0x200)[((d >>  8) & 0xFF)]
+        ^ (table + 0x100)[((d >> 16) & 0xFF)]
+        ^ (table + 0x000)[((d >> 24))];
+  }
+  for (; size > 0; size--, p++)
+    v = CRC64_UPDATE_BYTE_2(v, *p);
+  return v;
+}
+
+#endif
+
+
+#ifndef MY_CPU_LE
+
+#define CRC_UINT64_SWAP(v) \
+      ((v >> 56) \
+    | ((v >> 40) & ((UInt64)0xFF <<  8)) \
+    | ((v >> 24) & ((UInt64)0xFF << 16)) \
+    | ((v >>  8) & ((UInt64)0xFF << 24)) \
+    | ((v <<  8) & ((UInt64)0xFF << 32)) \
+    | ((v << 24) & ((UInt64)0xFF << 40)) \
+    | ((v << 40) & ((UInt64)0xFF << 48)) \
+    | ((v << 56)))
+
+#define CRC64_UPDATE_BYTE_2_BE(crc, b) (table[(Byte)((crc) >> 56) ^ (b)] ^ ((crc) << 8))
+
+UInt64 MY_FAST_CALL XzCrc64UpdateT1_BeT4(UInt64 v, const void *data, size_t size, const UInt64 *table);
+UInt64 MY_FAST_CALL XzCrc64UpdateT1_BeT4(UInt64 v, const void *data, size_t size, const UInt64 *table)
+{
+  const Byte *p = (const Byte *)data;
+  table += 0x100;
+  v = CRC_UINT64_SWAP(v);
+  for (; size > 0 && ((unsigned)(ptrdiff_t)p & 3) != 0; size--, p++)
+    v = CRC64_UPDATE_BYTE_2_BE(v, *p);
+  for (; size >= 4; size -= 4, p += 4)
+  {
+    UInt32 d = (UInt32)(v >> 32) ^ *(const UInt32 *)(const void *)p;
+    v = (v << 32)
+        ^ (table + 0x000)[((d      ) & 0xFF)]
+        ^ (table + 0x100)[((d >>  8) & 0xFF)]
+        ^ (table + 0x200)[((d >> 16) & 0xFF)]
+        ^ (table + 0x300)[((d >> 24))];
+  }
+  for (; size > 0; size--, p++)
+    v = CRC64_UPDATE_BYTE_2_BE(v, *p);
+  return CRC_UINT64_SWAP(v);
+}
+
+#endif
-- 
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