Add crc32c inline function, allows compilation on 32-bit systems

32-bit code still can use crc32c instructions, but it operates
on 32 registers

Change-Id: I9bb6b0b59635d6ea6a753584676ebcf59c8f6584
Signed-off-by: Damjan Marion <damarion@cisco.com>

1 files changed, 58 insertions, 0 deletions

diff --git a/src/vppinfra/crc32.h b/src/vppinfra/crc32.h
new file mode 100644
index 00000000000..abb2953fb4d
--- /dev/null
+++ b/src/vppinfra/crc32.h
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2015 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef __included_crc32_h__
+#define __included_crc32_h__
+
+#if __SSE4_2__
+#include <x86intrin.h>
+
+static_always_inline u32
+clib_crc32c (u8 * s, int len)
+{
+  u32 v = 0;
+
+#if __x86_64__
+  for (; len >= 8; len -= 8, s += 8)
+    v = _mm_crc32_u64 (v, *((u64 *) s));
+#else
+  /* workaround weird GCC bug when using _mm_crc32_u32
+     which happens with -O2 optimization */
+  volatile ("":::"memory");
+#endif
+
+  for (; len >= 4; len -= 4, s += 4)
+    v = _mm_crc32_u32 (v, *((u32 *) s));
+
+  for (; len >= 2; len -= 2, s += 2)
+    v = _mm_crc32_u16 (v, *((u16 *) s));
+
+  for (; len >= 1; len -= 1, s += 1)
+    v = _mm_crc32_u8 (v, *((u16 *) s));
+
+  return v;
+}
+
+#endif
+
+#endif /* __included_crc32_h__ */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */