Speed up CRC32 calculation on ARM64

The CRC32 instructions in ARM64 can calculate the CRC32 result
for 8 bytes in a single operation, making the use of ARM64
instructions much faster compared to the general CRC32 algorithm.

Optimized CRC32 will be enabled if ARM64 has CRC extension
running on Linux.

Signed-off-by: Chenxi Mao <chenxi.mao2013@gmail.com>

1 files changed, 109 insertions, 0 deletions

diff --git a/src/liblzma/check/crc32_aarch64.h b/src/liblzma/check/crc32_aarch64.h
new file mode 100644
index 00000000..77b14af4
--- /dev/null
+++ b/src/liblzma/check/crc32_aarch64.h
@@ -0,0 +1,109 @@
+///////////////////////////////////////////////////////////////////////////////
+//
+/// \file       crc32_aarch64.c
+/// \brief      CRC32 calculation with aarch64 optimization
+//
+//  Authors:    Chenxi Mao
+//
+//  This file has been put into the public domain.
+//  You can do whatever you want with this file.
+//
+///////////////////////////////////////////////////////////////////////////////
+#ifdef LZMA_CRC_CRC32_AARCH64_H
+#	error crc_arm64_clmul.h was included twice.
+#endif
+#define LZMA_CRC_CRC32_AARCH64_H
+#include <sys/auxv.h>
+// EDG-based compilers (Intel's classic compiler and compiler for E2K) can
+// define __GNUC__ but the attribute must not be used with them.
+// The new Clang-based ICX needs the attribute.
+//
+// NOTE: Build systems check for this too, keep them in sync with this.
+#if (defined(__GNUC__) || defined(__clang__)) && !defined(__EDG__)
+#	define crc_attr_target \
+        __attribute__((__target__("+crc")))
+#else
+#	define crc_attr_target
+#endif
+#ifdef BUILDING_CRC32_AARCH64
+crc_attr_target
+crc_attr_no_sanitize_address
+static uint32_t
+crc32_arch_optimized(const uint8_t *buf, size_t size, uint32_t crc)
+{
+	crc = ~crc;
+	while ((uintptr_t)(buf) & 7) {
+		crc = __builtin_aarch64_crc32b(crc, *buf);
+		buf++;
+		size--;
+	}
+	for (;size>=8;size-=8,buf+=8) {
+		crc = __builtin_aarch64_crc32x(crc, aligned_read64le(buf));
+	}
+	for (;size>0;size--,buf++)
+		crc = __builtin_aarch64_crc32b(crc, *buf);
+	return ~crc;
+}
+#endif
+#ifdef BUILDING_CRC64_AARCH64
+//FIXME: there is no crc64_arch_optimized implementation,
+// to make compiler happy, add crc64_generic here.
+#ifdef WORDS_BIGENDIAN
+#	define A1(x) ((x) >> 56)
+#else
+#	define A1 A
+#endif
+crc_attr_target
+crc_attr_no_sanitize_address
+static uint64_t
+crc64_arch_optimized(const uint8_t *buf, size_t size, uint64_t crc)
+{
+	crc = ~crc;
+
+#ifdef WORDS_BIGENDIAN
+	crc = bswap64(crc);
+#endif
+
+	if (size > 4) {
+		while ((uintptr_t)(buf) & 3) {
+			crc = lzma_crc64_table[0][*buf++ ^ A1(crc)] ^ S8(crc);
+			--size;
+		}
+
+		const uint8_t *const limit = buf + (size & ~(size_t)(3));
+		size &= (size_t)(3);
+
+		while (buf < limit) {
+#ifdef WORDS_BIGENDIAN
+			const uint32_t tmp = (uint32_t)(crc >> 32)
+					^ aligned_read32ne(buf);
+#else
+			const uint32_t tmp = (uint32_t)crc
+					^ aligned_read32ne(buf);
+#endif
+			buf += 4;
+
+			crc = lzma_crc64_table[3][A(tmp)]
+			    ^ lzma_crc64_table[2][B(tmp)]
+			    ^ S32(crc)
+			    ^ lzma_crc64_table[1][C(tmp)]
+			    ^ lzma_crc64_table[0][D(tmp)];
+		}
+	}
+
+	while (size-- != 0)
+		crc = lzma_crc64_table[0][*buf++ ^ A1(crc)] ^ S8(crc);
+
+#ifdef WORDS_BIGENDIAN
+	crc = bswap64(crc);
+#endif
+
+	return ~crc;
+}
+#endif
+static inline bool
+is_arch_extension_supported(void)
+{
+	return (getauxval(AT_HWCAP) & HWCAP_CRC32)!=0;
+}
+