linux/lib/lz4/lz4defs.h

/*
 * lz4defs.h -- architecture specific defines
 *
 * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

/*
 * Detects 64 bits mode
 */
#if defined(CONFIG_64BIT)
#define LZ4_ARCH64 1
#else
#define LZ4_ARCH64 0
#endif

/*
 * Architecture-specific macros
 */
#define BYTE	u8
typedef struct _U16_S { u16 v; } U16_S;
typedef struct _U32_S { u32 v; } U32_S;
typedef struct _U64_S { u64 v; } U64_S;
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)

#define A16(x) (((U16_S *)(x))->v)
#define A32(x) (((U32_S *)(x))->v)
#define A64(x) (((U64_S *)(x))->v)

#define PUT4(s, d) (A32(d) = A32(s))
#define PUT8(s, d) (A64(d) = A64(s))

#define LZ4_READ_LITTLEENDIAN_16(d, s, p)	\
	(d = s - A16(p))

#define LZ4_WRITE_LITTLEENDIAN_16(p, v)	\
	do {	\
		A16(p) = v; \
		p += 2; \
	} while (0)
#else /* CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS */

#define A64(x) get_unaligned((u64 *)&(((U16_S *)(x))->v))
#define A32(x) get_unaligned((u32 *)&(((U16_S *)(x))->v))
#define A16(x) get_unaligned((u16 *)&(((U16_S *)(x))->v))

#define PUT4(s, d) \
	put_unaligned(get_unaligned((const u32 *) s), (u32 *) d)
#define PUT8(s, d) \
	put_unaligned(get_unaligned((const u64 *) s), (u64 *) d)

#define LZ4_READ_LITTLEENDIAN_16(d, s, p)	\
	(d = s - get_unaligned_le16(p))

#define LZ4_WRITE_LITTLEENDIAN_16(p, v)			\
	do {						\
		put_unaligned_le16(v, (u16 *)(p));	\
		p += 2;					\
	} while (0)
#endif

#define COPYLENGTH 8
#define ML_BITS  4
#define ML_MASK  ((1U << ML_BITS) - 1)
#define RUN_BITS (8 - ML_BITS)
#define RUN_MASK ((1U << RUN_BITS) - 1)
#define MEMORY_USAGE	14
#define MINMATCH	4
#define SKIPSTRENGTH	6
#define LASTLITERALS	5
#define MFLIMIT		(COPYLENGTH + MINMATCH)
#define MINLENGTH	(MFLIMIT + 1)
#define MAXD_LOG	16
#define MAXD		(1 << MAXD_LOG)
#define MAXD_MASK	(u32)(MAXD - 1)
#define MAX_DISTANCE	(MAXD - 1)
#define HASH_LOG	(MAXD_LOG - 1)
#define HASHTABLESIZE	(1 << HASH_LOG)
#define MAX_NB_ATTEMPTS	256
#define OPTIMAL_ML	(int)((ML_MASK-1)+MINMATCH)
#define LZ4_64KLIMIT	((1<<16) + (MFLIMIT - 1))
#define HASHLOG64K	((MEMORY_USAGE - 2) + 1)
#define HASH64KTABLESIZE	(1U << HASHLOG64K)
#define LZ4_HASH_VALUE(p)	(((A32(p)) * 2654435761U) >> \
				((MINMATCH * 8) - (MEMORY_USAGE-2)))
#define LZ4_HASH64K_VALUE(p)	(((A32(p)) * 2654435761U) >> \
				((MINMATCH * 8) - HASHLOG64K))
#define HASH_VALUE(p)		(((A32(p)) * 2654435761U) >> \
				((MINMATCH * 8) - HASH_LOG))

#if LZ4_ARCH64/* 64-bit */
#define STEPSIZE 8

#define LZ4_COPYSTEP(s, d)	\
	do {			\
		PUT8(s, d);	\
		d += 8;		\
		s += 8;		\
	} while (0)

#define LZ4_COPYPACKET(s, d)	LZ4_COPYSTEP(s, d)

#define LZ4_SECURECOPY(s, d, e)			\
	do {					\
		if (d < e) {			\
			LZ4_WILDCOPY(s, d, e);	\
		}				\
	} while (0)
#define HTYPE u32

#ifdef __BIG_ENDIAN
#define LZ4_NBCOMMONBYTES(val) (__builtin_clzll(val) >> 3)
#else
#define LZ4_NBCOMMONBYTES(val) (__builtin_ctzll(val) >> 3)
#endif

#else	/* 32-bit */
#define STEPSIZE 4

#define LZ4_COPYSTEP(s, d)	\
	do {			\
		PUT4(s, d);	\
		d += 4;		\
		s += 4;		\
	} while (0)

#define LZ4_COPYPACKET(s, d)		\
	do {				\
		LZ4_COPYSTEP(s, d);	\
		LZ4_COPYSTEP(s, d);	\
	} while (0)

#define LZ4_SECURECOPY	LZ4_WILDCOPY
#define HTYPE const u8*

#ifdef __BIG_ENDIAN
#define LZ4_NBCOMMONBYTES(val) (__builtin_clz(val) >> 3)
#else
#define LZ4_NBCOMMONBYTES(val) (__builtin_ctz(val) >> 3)
#endif

#endif

#define LZ4_WILDCOPY(s, d, e)		\
	do {				\
		LZ4_COPYPACKET(s, d);	\
	} while (d < e)

#define LZ4_BLINDCOPY(s, d, l)	\
	do {	\
		u8 *e = (d) + l;	\
		LZ4_WILDCOPY(s, d, e);	\
		d = e;	\
	} while (0)