arm: Add support for armv8 CRC32 instructions

This patch introduces the ARM A32/T32/A64 CRC Instructions, which are
mandatory since ARMv8.1. The UNPREDICTABLE behaviours are implemented as
follows:
1) CRC32(C)X (64 bit) instructions are decoded as Undefined in Aarch32
2) The instructions support predication in Aarch32
3) Using R15(PC) as source/dest operand is permitted in Aarch32

Change-Id: Iaf29b05874e1370c7615da79a07f111ded17b6cc
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/5521
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

1 files changed, 81 insertions, 0 deletions

diff --git a/src/base/crc.hh b/src/base/crc.hh
new file mode 100644
index 000000000..132a15c13
--- /dev/null
+++ b/src/base/crc.hh
@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2017 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Giacomo Travaglini
+ */
+
+#ifndef __BASE_CRC_HH__
+#define __BASE_CRC_HH__
+
+#include "base/bitfield.hh"
+
+/**
+ * Evaluate the CRC32 of the first size bytes of a data buffer,
+ * using a specific polynomium and an initial value.
+ * The crc is accomplished by reversing the input, the initial value
+ * and the output (remainder).
+ *
+ * @param data: Input data buffer pointer
+ * @param crc:  Initial value of the checksum
+ * @param size: Number of bytes
+ *
+ * @return 32-bit remainder of the checksum
+ */
+template <uint32_t Poly>
+uint32_t
+crc32(const uint8_t* data, uint32_t crc, std::size_t size)
+{
+    uint32_t byte = 0;
+
+    crc = reverseBits(crc);
+    for (auto i = 0; i < size; i++) {
+        byte = data[i];
+
+        // 32-bit reverse
+        byte = reverseBits(byte);
+        for (auto j = 0; j <= 7; j++) {
+            if ((int)(crc ^ byte) < 0) {
+                crc = (crc << 1) ^ Poly;
+            } else {
+                crc = crc << 1;
+            }
+            byte = byte << 1;
+        }
+    }
+    return reverseBits(crc);
+}
+
+#endif // __BASE_CRC_HH__