initial code repo

[stor4nfv.git] / src / ceph / src / common / crc32c_ppc.c

diff --git a/src/ceph/src/common/crc32c_ppc.c b/src/ceph/src/common/crc32c_ppc.c
new file mode 100644 (file)
index 0000000..43756e2
--- /dev/null
+++ b/src/ceph/src/common/crc32c_ppc.c
@@ -0,0 +1,148 @@
+/* Copyright (C) 2017 International Business Machines Corp.
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+#define CRC_TABLE
+#define FAST_ZERO_TABLE
+
+#include "acconfig.h"
+#include "include/int_types.h"
+#include "crc32c_ppc_constants.h"
+#include "reverse.h"
+
+#include <stdlib.h>
+#include <strings.h>
+
+#define VMX_ALIGN      16
+#define VMX_ALIGN_MASK (VMX_ALIGN-1)
+
+#ifdef REFLECT
+static unsigned int crc32_align(unsigned int crc, unsigned char const *p,
+                                unsigned long len)
+{
+  while (len--)
+    crc = crc_table[(crc ^ *p++) & 0xff] ^ (crc >> 8);
+  return crc;
+}
+#else
+static unsigned int crc32_align(unsigned int crc, unsigned char const *p,
+                                unsigned long len)
+{
+  while (len--)
+    crc = crc_table[((crc >> 24) ^ *p++) & 0xff] ^ (crc << 8);
+  return crc;
+}
+#endif
+
+#ifdef HAVE_POWER8
+static inline unsigned long polynomial_multiply(unsigned int a, unsigned int b) {
+        vector unsigned int va = {a, 0, 0, 0};
+        vector unsigned int vb = {b, 0, 0, 0};
+        vector unsigned long vt;
+
+        __asm__("vpmsumw %0,%1,%2" : "=v"(vt) : "v"(va), "v"(vb));
+
+        return vt[0];
+}
+
+unsigned int barrett_reduction(unsigned long val);
+
+static inline unsigned int gf_multiply(unsigned int a, unsigned int b) {
+        return barrett_reduction(polynomial_multiply(a, b));
+}
+
+unsigned int append_zeros(unsigned int crc, unsigned long length) {
+        unsigned long i = 0;
+
+        while (length) {
+                if (length & 1) {
+                        crc = gf_multiply(crc, crc_zero[i]);
+                }
+                i++;
+                length /= 2;
+        }
+
+        return crc;
+}
+
+
+unsigned int __crc32_vpmsum(unsigned int crc, unsigned char const *p,
+                            unsigned long len);
+
+static uint32_t crc32_vpmsum(uint32_t crc, unsigned char const *data,
+                             unsigned len)
+{
+  unsigned int prealign;
+  unsigned int tail;
+
+#ifdef CRC_XOR
+  crc ^= 0xffffffff;
+#endif
+
+  if (len < VMX_ALIGN + VMX_ALIGN_MASK) {
+    crc = crc32_align(crc, data, (unsigned long)len);
+    goto out;
+  }
+
+  if ((unsigned long)data & VMX_ALIGN_MASK) {
+    prealign = VMX_ALIGN - ((unsigned long)data & VMX_ALIGN_MASK);
+    crc = crc32_align(crc, data, prealign);
+    len -= prealign;
+    data += prealign;
+  }
+
+  crc = __crc32_vpmsum(crc, data, (unsigned long)len & ~VMX_ALIGN_MASK);
+
+  tail = len & VMX_ALIGN_MASK;
+  if (tail) {
+    data += len & ~VMX_ALIGN_MASK;
+    crc = crc32_align(crc, data, tail);
+  }
+
+out:
+#ifdef CRC_XOR
+  crc ^= 0xffffffff;
+#endif
+
+  return crc;
+}
+
+/* This wrapper function works around the fact that crc32_vpmsum 
+ * does not gracefully handle the case where the data pointer is NULL.
+ */
+uint32_t ceph_crc32c_ppc(uint32_t crc, unsigned char const *data, unsigned len)
+{
+  if (!data) {
+    /* Handle the NULL buffer case. */
+#ifdef REFLECT
+    crc = reverse_bits(crc);
+#endif
+
+    crc = append_zeros(crc, len);
+
+#ifdef REFLECT
+    crc = reverse_bits(crc);
+#endif
+  } else {
+    /* Handle the valid buffer case. */
+    crc = crc32_vpmsum(crc, data, (unsigned long)len);
+  }
+  return crc;
+}
+
+#else /* HAVE_POWER8 */
+
+/* This symbol has to exist on non-ppc architectures (and on legacy
+ * ppc systems using power7 or below) in order to compile properly
+ * there, even though it won't be called.
+ */
+uint32_t ceph_crc32c_ppc(uint32_t crc, unsigned char const *data, unsigned len)
+{
+  return 0;
+}
+
+#endif /* HAVE_POWER8 */