libeio/ecb.h

/*
 * libecb - http://software.schmorp.de/pkg/libecb
 *
 * Copyright (©) 2009-2011 Marc Alexander Lehmann <libecb@schmorp.de>
 * Copyright (©) 2011 Emanuele Giaquinta
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modifica-
 * tion, are permitted provided that the following conditions are met:
 *
 *   1.  Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 *
 *   2.  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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
 * CIAL, 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 OTH-
 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef ECB_H
#define ECB_H

#ifdef _WIN32
  typedef   signed char   int8_t;
  typedef unsigned char  uint8_t;
  typedef   signed short  int16_t;
  typedef unsigned short uint16_t;
  typedef   signed int    int32_t;
  typedef unsigned int   uint32_t;
  #if __GNUC__
    typedef   signed long long int64_t;
    typedef unsigned long long uint64_t;
  #else /* _MSC_VER || __BORLANDC__ */
    typedef   signed __int64   int64_t;
    typedef unsigned __int64   uint64_t;
  #endif
#else
  #include <inttypes.h>
#endif

/* many compilers define _GNUC_ to some versions but then only implement
 * what their idiot authors think are the "more important" extensions,
 * causing enourmous grief in return for some better fake benchmark numbers.
 * or so.
 * we try to detect these and simply assume they are not gcc - if they have
 * an issue with that they should have done it right in the first place.
 */
#ifndef ECB_GCC_VERSION
  #if !defined(__GNUC_MINOR__) || defined(__INTEL_COMPILER) || defined(__SUNPRO_C) || defined(__SUNPRO_CC) || defined(__llvm__) || defined(__clang__)
    #define ECB_GCC_VERSION(major,minor) 0
  #else
    #define ECB_GCC_VERSION(major,minor) (__GNUC__ > (major) || (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor)))
  #endif
#endif

/*****************************************************************************/

#ifndef ECB_MEMORY_FENCE
  #if ECB_GCC_VERSION(2,5)
    #if __x86
      #define ECB_MEMORY_FENCE         __asm__ __volatile__ ("lock; orb $0, -1(%%esp)" : : : "memory")
      #define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
      #define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE /* better be safe than sorry */
    #elif __amd64
      #define ECB_MEMORY_FENCE         __asm__ __volatile__ ("mfence" : : : "memory")
      #define ECB_MEMORY_FENCE_ACQUIRE __asm__ __volatile__ ("lfence" : : : "memory")
      #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("sfence")
    #endif
  #endif
#endif

#ifndef ECB_MEMORY_FENCE
  #if ECB_GCC_VERSION(4,4)
    #define ECB_MEMORY_FENCE         __sync_synchronize ()
    #define ECB_MEMORY_FENCE_ACQUIRE ({ char dummy = 0; __sync_lock_test_and_set (&dummy, 1); })
    #define ECB_MEMORY_FENCE_RELEASE ({ char dummy = 1; __sync_lock_release      (&dummy   ); })
  #elif _MSC_VER >= 1400 && 0 /* TODO: only true when using volatiles */
    #define ECB_MEMORY_FENCE         do { } while (0)
    #define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
    #define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
  #elif defined(_WIN32)
    #include <WinNT.h>
    #define ECB_MEMORY_FENCE         MemoryBarrier ()
    #define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
    #define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
  #endif
#endif

#ifndef ECB_MEMORY_FENCE
  #include <pthread.h>

  static pthread_mutex_t ecb_mf_lock = PTHREAD_MUTEX_INITIALIZER;
  #define ECB_MEMORY_FENCE do { pthread_mutex_lock (&ecb_mf_lock); pthread_mutex_unlock (&ecb_mf_lock); } while (0)
  #define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
  #define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
#endif

/*****************************************************************************/

#define ECB_C99 (__STDC_VERSION__ >= 199901L)

#if __cplusplus
  #define ecb_inline static inline
#elif ECB_GCC_VERSION(2,5)
  #define ecb_inline static __inline__
#elif ECB_C99
  #define ecb_inline static inline
#else
  #define ecb_inline static
#endif

#if ECB_GCC_VERSION(3,3)
  #define ecb_restrict __restrict__
#elif ECB_C99
  #define ecb_restrict restrict
#else
  #define ecb_restrict
#endif

typedef int ecb_bool;

#define ECB_CONCAT_(a, b) a ## b
#define ECB_CONCAT(a, b) ECB_CONCAT_(a, b)
#define ECB_STRINGIFY_(a) # a
#define ECB_STRINGIFY(a) ECB_STRINGIFY_(a)

#define ecb_function_ ecb_inline

#if ECB_GCC_VERSION(3,1)
  #define ecb_attribute(attrlist)        __attribute__(attrlist)
  #define ecb_is_constant(expr)          __builtin_constant_p (expr)
  #define ecb_expect(expr,value)         __builtin_expect ((expr),(value))
  #define ecb_prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality)
#else
  #define ecb_attribute(attrlist)
  #define ecb_is_constant(expr)          0
  #define ecb_expect(expr,value)         (expr)
  #define ecb_prefetch(addr,rw,locality)
#endif

/* no emulation for ecb_decltype */
#if ECB_GCC_VERSION(4,5)
  #define ecb_decltype(x) __decltype(x)
#elif ECB_GCC_VERSION(3,0)
  #define ecb_decltype(x) __typeof(x)
#endif

#define ecb_noinline   ecb_attribute ((__noinline__))
#define ecb_noreturn   ecb_attribute ((__noreturn__))
#define ecb_unused     ecb_attribute ((__unused__))
#define ecb_const      ecb_attribute ((__const__))
#define ecb_pure       ecb_attribute ((__pure__))

#if ECB_GCC_VERSION(4,3)
  #define ecb_artificial ecb_attribute ((__artificial__))
  #define ecb_hot        ecb_attribute ((__hot__))
  #define ecb_cold       ecb_attribute ((__cold__))
#else
  #define ecb_artificial
  #define ecb_hot
  #define ecb_cold
#endif

/* put around conditional expressions if you are very sure that the  */
/* expression is mostly true or mostly false. note that these return */
/* booleans, not the expression.                                     */
#define ecb_expect_false(expr) ecb_expect (!!(expr), 0)
#define ecb_expect_true(expr)  ecb_expect (!!(expr), 1)
/* for compatibility to the rest of the world */
#define ecb_likely(expr)   ecb_expect_true  (expr)
#define ecb_unlikely(expr) ecb_expect_false (expr)

/* count trailing zero bits and count # of one bits */
#if ECB_GCC_VERSION(3,4)
  /* we assume int == 32 bit, long == 32 or 64 bit and long long == 64 bit */
  #define ecb_ld32(x)      (__builtin_clz      (x) ^ 31)
  #define ecb_ld64(x)      (__builtin_clzll    (x) ^ 63)
  #define ecb_ctz32(x)      __builtin_ctz      (x)
  #define ecb_ctz64(x)      __builtin_ctzll    (x)
  #define ecb_popcount32(x) __builtin_popcount (x)
  /* no popcountll */
#else
  ecb_function_ int ecb_ctz32 (uint32_t x) ecb_const;
  ecb_function_ int
  ecb_ctz32 (uint32_t x)
  {
    int r = 0;

    x &= ~x + 1; /* this isolates the lowest bit */

#if ECB_branchless_on_i386
    r += !!(x & 0xaaaaaaaa) << 0;
    r += !!(x & 0xcccccccc) << 1;
    r += !!(x & 0xf0f0f0f0) << 2;
    r += !!(x & 0xff00ff00) << 3;
    r += !!(x & 0xffff0000) << 4;
#else
    if (x & 0xaaaaaaaa) r +=  1;
    if (x & 0xcccccccc) r +=  2;
    if (x & 0xf0f0f0f0) r +=  4;
    if (x & 0xff00ff00) r +=  8;
    if (x & 0xffff0000) r += 16;
#endif

    return r;
  }

  ecb_function_ int ecb_ctz64 (uint64_t x) ecb_const;
  ecb_function_ int
  ecb_ctz64 (uint64_t x)
  {
    int shift = x & 0xffffffffU ? 0 : 32;
    return ecb_ctz32 (x >> shift) + shift;
  }

  ecb_function_ int ecb_popcount32 (uint32_t x) ecb_const;
  ecb_function_ int
  ecb_popcount32 (uint32_t x)
  {
    x -=  (x >> 1) & 0x55555555;
    x  = ((x >> 2) & 0x33333333) + (x & 0x33333333);
    x  = ((x >> 4) + x) & 0x0f0f0f0f;
    x *= 0x01010101;

    return x >> 24;
  }

  /* you have the choice beetween something with a table lookup, */
  /* something using lots of bit arithmetic and a simple loop */
  /* we went for the loop */
  ecb_function_ int ecb_ld32 (uint32_t x) ecb_const;
  ecb_function_ int ecb_ld32 (uint32_t x)
  {
    int r = 0;

    if (x >> 16) { x >>= 16; r += 16; }
    if (x >>  8) { x >>=  8; r +=  8; }
    if (x >>  4) { x >>=  4; r +=  4; }
    if (x >>  2) { x >>=  2; r +=  2; }
    if (x >>  1) {           r +=  1; }

    return r;
  }

  ecb_function_ int ecb_ld64 (uint64_t x) ecb_const;
  ecb_function_ int ecb_ld64 (uint64_t x)
  {
    int r = 0;

    if (x >> 32) { x >>= 32; r += 32; }

    return r + ecb_ld32 (x);
  }
#endif

/* popcount64 is only available on 64 bit cpus as gcc builtin */
/* so for this version we are lazy */
ecb_function_ int ecb_popcount64 (uint64_t x) ecb_const;
ecb_function_ int
ecb_popcount64 (uint64_t x)
{
  return ecb_popcount32 (x) + ecb_popcount32 (x >> 32);
}

ecb_inline uint8_t  ecb_rotl8  (uint8_t  x, unsigned int count) ecb_const;
ecb_inline uint8_t  ecb_rotr8  (uint8_t  x, unsigned int count) ecb_const;
ecb_inline uint16_t ecb_rotl16 (uint16_t x, unsigned int count) ecb_const;
ecb_inline uint16_t ecb_rotr16 (uint16_t x, unsigned int count) ecb_const;
ecb_inline uint32_t ecb_rotl32 (uint32_t x, unsigned int count) ecb_const;
ecb_inline uint32_t ecb_rotr32 (uint32_t x, unsigned int count) ecb_const;
ecb_inline uint64_t ecb_rotl64 (uint64_t x, unsigned int count) ecb_const;
ecb_inline uint64_t ecb_rotr64 (uint64_t x, unsigned int count) ecb_const;

ecb_inline uint8_t  ecb_rotl8  (uint8_t  x, unsigned int count) { return (x >> ( 8 - count)) | (x << count); }
ecb_inline uint8_t  ecb_rotr8  (uint8_t  x, unsigned int count) { return (x << ( 8 - count)) | (x >> count); }
ecb_inline uint16_t ecb_rotl16 (uint16_t x, unsigned int count) { return (x >> (16 - count)) | (x << count); }
ecb_inline uint16_t ecb_rotr16 (uint16_t x, unsigned int count) { return (x << (16 - count)) | (x >> count); }
ecb_inline uint32_t ecb_rotl32 (uint32_t x, unsigned int count) { return (x >> (32 - count)) | (x << count); }
ecb_inline uint32_t ecb_rotr32 (uint32_t x, unsigned int count) { return (x << (32 - count)) | (x >> count); }
ecb_inline uint64_t ecb_rotl64 (uint64_t x, unsigned int count) { return (x >> (64 - count)) | (x << count); }
ecb_inline uint64_t ecb_rotr64 (uint64_t x, unsigned int count) { return (x << (64 - count)) | (x >> count); }

#if ECB_GCC_VERSION(4,3)
  #define ecb_bswap16(x) (__builtin_bswap32 (x) >> 16)
  #define ecb_bswap32(x)  __builtin_bswap32 (x)
  #define ecb_bswap64(x)  __builtin_bswap64 (x)
#else
  ecb_function_ uint16_t ecb_bswap16 (uint16_t x) ecb_const;
  ecb_function_ uint16_t
  ecb_bswap16 (uint16_t x)
  {
    return ecb_rotl16 (x, 8);
  }

  ecb_function_ uint32_t ecb_bswap32 (uint32_t x) ecb_const;
  ecb_function_ uint32_t
  ecb_bswap32 (uint32_t x)
  {
    return (((uint32_t)ecb_bswap16 (x)) << 16) | ecb_bswap16 (x >> 16);
  }

  ecb_function_ uint64_t ecb_bswap64 (uint64_t x) ecb_const;
  ecb_function_ uint64_t
  ecb_bswap64 (uint64_t x)
  {
    return (((uint64_t)ecb_bswap32 (x)) << 32) | ecb_bswap32 (x >> 32);
  }
#endif

#if ECB_GCC_VERSION(4,5)
  #define ecb_unreachable() __builtin_unreachable ()
#else
  /* this seems to work fine, but gcc always emits a warning for it :/ */
  ecb_function_ void ecb_unreachable (void) ecb_noreturn;
  ecb_function_ void ecb_unreachable (void) { }
#endif

/* try to tell the compiler that some condition is definitely true */
#define ecb_assume(cond) do { if (!(cond)) ecb_unreachable (); } while (0)

ecb_function_ unsigned char ecb_byteorder_helper (void) ecb_const;
ecb_function_ unsigned char
ecb_byteorder_helper (void)
{
  const uint32_t u = 0x11223344;
  return *(unsigned char *)&u;
}

ecb_function_ ecb_bool ecb_big_endian    (void) ecb_const;
ecb_function_ ecb_bool ecb_big_endian    (void) { return ecb_byteorder_helper () == 0x11; }
ecb_function_ ecb_bool ecb_little_endian (void) ecb_const;
ecb_function_ ecb_bool ecb_little_endian (void) { return ecb_byteorder_helper () == 0x44; }

#if ECB_GCC_VERSION(3,0) || ECB_C99
  #define ecb_mod(m,n) ((m) % (n) + ((m) % (n) < 0 ? (n) : 0))
#else
  #define ecb_mod(m,n) ((m) < 0 ? ((n) - 1 - ((-1 - (m)) % (n))) : ((m) % (n)))
#endif

#if ecb_cplusplus_does_not_suck
  /* does not work for local types (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2657.htm) */
  template<typename T, int N>
  static inline int ecb_array_length (const T (&arr)[N])
  {
    return N;
  }
#else
  #define ecb_array_length(name) (sizeof (name) / sizeof (name [0]))
#endif

#endif

Revision:	1.6
Committed:	Tue Jul 26 11:07:08 2011 UTC (12 years, 9 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.5:	+2 -1 lines
Log Message:	better rename()
#	User	Rev	Content
1	root	1.1	/*
2			* libecb - http://software.schmorp.de/pkg/libecb
3			*
4			* Copyright (©) 2009-2011 Marc Alexander Lehmann <libecb@schmorp.de>
5			* Copyright (©) 2011 Emanuele Giaquinta
6			* All rights reserved.
7			*
8			* Redistribution and use in source and binary forms, with or without modifica-
9			* tion, are permitted provided that the following conditions are met:
10			*
11			* 1. Redistributions of source code must retain the above copyright notice,
12			* this list of conditions and the following disclaimer.
13			*
14			* 2. Redistributions in binary form must reproduce the above copyright
15			* notice, this list of conditions and the following disclaimer in the
16			* documentation and/or other materials provided with the distribution.
17			*
18			* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
19			* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
20			* CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
21			* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
22			* CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
23			* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
24			* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
25			* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
26			* ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
27			* OF THE POSSIBILITY OF SUCH DAMAGE.
28			*/
29
30			#ifndef ECB_H
31			#define ECB_H
32
33	root	1.2	#ifdef _WIN32
34			typedef signed char int8_t;
35			typedef unsigned char uint8_t;
36			typedef signed short int16_t;
37			typedef unsigned short uint16_t;
38			typedef signed int int32_t;
39			typedef unsigned int uint32_t;
40			#if __GNUC__
41			typedef signed long long int64_t;
42			typedef unsigned long long uint64_t;
43	root	1.3	#else /* _MSC_VER \|\| __BORLANDC__ */
44	root	1.2	typedef signed __int64 int64_t;
45			typedef unsigned __int64 uint64_t;
46			#endif
47			#else
48			#include <inttypes.h>
49			#endif
50	root	1.1
51			/* many compilers define _GNUC_ to some versions but then only implement
52			* what their idiot authors think are the "more important" extensions,
53			* causing enourmous grief in return for some better fake benchmark numbers.
54			* or so.
55			* we try to detect these and simply assume they are not gcc - if they have
56			* an issue with that they should have done it right in the first place.
57			*/
58			#ifndef ECB_GCC_VERSION
59	root	1.2	#if !defined(__GNUC_MINOR__) \|\| defined(__INTEL_COMPILER) \|\| defined(__SUNPRO_C) \|\| defined(__SUNPRO_CC) \|\| defined(__llvm__) \|\| defined(__clang__)
60			#define ECB_GCC_VERSION(major,minor) 0
61			#else
62			#define ECB_GCC_VERSION(major,minor) (__GNUC__ > (major) \|\| (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor)))
63			#endif
64	root	1.1	#endif
65
66	root	1.4	/*****************************************************************************/
67
68			#ifndef ECB_MEMORY_FENCE
69			#if ECB_GCC_VERSION(2,5)
70			#if __x86
71	root	1.5	#define ECB_MEMORY_FENCE __asm__ __volatile__ ("lock; orb $0, -1(%%esp)" : : : "memory")
72	root	1.4	#define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
73			#define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE /* better be safe than sorry */
74			#elif __amd64
75			#define ECB_MEMORY_FENCE __asm__ __volatile__ ("mfence" : : : "memory")
76			#define ECB_MEMORY_FENCE_ACQUIRE __asm__ __volatile__ ("lfence" : : : "memory")
77			#define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("sfence")
78			#endif
79			#endif
80			#endif
81
82			#ifndef ECB_MEMORY_FENCE
83			#if ECB_GCC_VERSION(4,4)
84			#define ECB_MEMORY_FENCE __sync_synchronize ()
85			#define ECB_MEMORY_FENCE_ACQUIRE ({ char dummy = 0; __sync_lock_test_and_set (&dummy, 1); })
86			#define ECB_MEMORY_FENCE_RELEASE ({ char dummy = 1; __sync_lock_release (&dummy ); })
87	root	1.5	#elif _MSC_VER >= 1400 && 0 /* TODO: only true when using volatiles */
88	root	1.4	#define ECB_MEMORY_FENCE do { } while (0)
89			#define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
90			#define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
91	root	1.6	#elif defined(_WIN32)
92			#include <WinNT.h>
93	root	1.4	#define ECB_MEMORY_FENCE MemoryBarrier ()
94			#define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
95			#define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
96			#endif
97			#endif
98
99			#ifndef ECB_MEMORY_FENCE
100			#include <pthread.h>
101
102			static pthread_mutex_t ecb_mf_lock = PTHREAD_MUTEX_INITIALIZER;
103			#define ECB_MEMORY_FENCE do { pthread_mutex_lock (&ecb_mf_lock); pthread_mutex_unlock (&ecb_mf_lock); } while (0)
104			#define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
105			#define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
106			#endif
107
108			/*****************************************************************************/
109
110	root	1.2	#define ECB_C99 (__STDC_VERSION__ >= 199901L)
111
112			#if __cplusplus
113			#define ecb_inline static inline
114			#elif ECB_GCC_VERSION(2,5)
115			#define ecb_inline static __inline__
116			#elif ECB_C99
117			#define ecb_inline static inline
118			#else
119			#define ecb_inline static
120			#endif
121
122			#if ECB_GCC_VERSION(3,3)
123			#define ecb_restrict __restrict__
124			#elif ECB_C99
125			#define ecb_restrict restrict
126	root	1.1	#else
127	root	1.2	#define ecb_restrict
128	root	1.1	#endif
129
130	root	1.2	typedef int ecb_bool;
131
132	root	1.1	#define ECB_CONCAT_(a, b) a ## b
133			#define ECB_CONCAT(a, b) ECB_CONCAT_(a, b)
134			#define ECB_STRINGIFY_(a) # a
135			#define ECB_STRINGIFY(a) ECB_STRINGIFY_(a)
136
137	root	1.2	#define ecb_function_ ecb_inline
138	root	1.1
139			#if ECB_GCC_VERSION(3,1)
140	root	1.2	#define ecb_attribute(attrlist) __attribute__(attrlist)
141			#define ecb_is_constant(expr) __builtin_constant_p (expr)
142			#define ecb_expect(expr,value) __builtin_expect ((expr),(value))
143			#define ecb_prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality)
144			#else
145			#define ecb_attribute(attrlist)
146			#define ecb_is_constant(expr) 0
147			#define ecb_expect(expr,value) (expr)
148			#define ecb_prefetch(addr,rw,locality)
149	root	1.1	#endif
150
151			/* no emulation for ecb_decltype */
152			#if ECB_GCC_VERSION(4,5)
153	root	1.2	#define ecb_decltype(x) __decltype(x)
154	root	1.1	#elif ECB_GCC_VERSION(3,0)
155	root	1.2	#define ecb_decltype(x) __typeof(x)
156	root	1.1	#endif
157
158			#define ecb_noinline ecb_attribute ((__noinline__))
159			#define ecb_noreturn ecb_attribute ((__noreturn__))
160			#define ecb_unused ecb_attribute ((__unused__))
161			#define ecb_const ecb_attribute ((__const__))
162			#define ecb_pure ecb_attribute ((__pure__))
163
164	root	1.2	#if ECB_GCC_VERSION(4,3)
165			#define ecb_artificial ecb_attribute ((__artificial__))
166			#define ecb_hot ecb_attribute ((__hot__))
167			#define ecb_cold ecb_attribute ((__cold__))
168			#else
169			#define ecb_artificial
170			#define ecb_hot
171			#define ecb_cold
172			#endif
173
174			/* put around conditional expressions if you are very sure that the */
175			/* expression is mostly true or mostly false. note that these return */
176			/* booleans, not the expression. */
177	root	1.1	#define ecb_expect_false(expr) ecb_expect (!!(expr), 0)
178			#define ecb_expect_true(expr) ecb_expect (!!(expr), 1)
179	root	1.2	/* for compatibility to the rest of the world */
180	root	1.1	#define ecb_likely(expr) ecb_expect_true (expr)
181			#define ecb_unlikely(expr) ecb_expect_false (expr)
182
183			/* count trailing zero bits and count # of one bits */
184			#if ECB_GCC_VERSION(3,4)
185	root	1.2	/* we assume int == 32 bit, long == 32 or 64 bit and long long == 64 bit */
186			#define ecb_ld32(x) (__builtin_clz (x) ^ 31)
187			#define ecb_ld64(x) (__builtin_clzll (x) ^ 63)
188			#define ecb_ctz32(x) __builtin_ctz (x)
189			#define ecb_ctz64(x) __builtin_ctzll (x)
190			#define ecb_popcount32(x) __builtin_popcount (x)
191			/* no popcountll */
192	root	1.1	#else
193	root	1.2	ecb_function_ int ecb_ctz32 (uint32_t x) ecb_const;
194			ecb_function_ int
195			ecb_ctz32 (uint32_t x)
196			{
197			int r = 0;
198
199			x &= ~x + 1; /* this isolates the lowest bit */
200
201	root	1.3	#if ECB_branchless_on_i386
202			r += !!(x & 0xaaaaaaaa) << 0;
203			r += !!(x & 0xcccccccc) << 1;
204			r += !!(x & 0xf0f0f0f0) << 2;
205			r += !!(x & 0xff00ff00) << 3;
206			r += !!(x & 0xffff0000) << 4;
207			#else
208	root	1.2	if (x & 0xaaaaaaaa) r += 1;
209			if (x & 0xcccccccc) r += 2;
210			if (x & 0xf0f0f0f0) r += 4;
211			if (x & 0xff00ff00) r += 8;
212			if (x & 0xffff0000) r += 16;
213	root	1.3	#endif
214	root	1.2
215			return r;
216			}
217
218			ecb_function_ int ecb_ctz64 (uint64_t x) ecb_const;
219			ecb_function_ int
220			ecb_ctz64 (uint64_t x)
221			{
222			int shift = x & 0xffffffffU ? 0 : 32;
223	root	1.3	return ecb_ctz32 (x >> shift) + shift;
224	root	1.2	}
225
226			ecb_function_ int ecb_popcount32 (uint32_t x) ecb_const;
227			ecb_function_ int
228			ecb_popcount32 (uint32_t x)
229			{
230			x -= (x >> 1) & 0x55555555;
231			x = ((x >> 2) & 0x33333333) + (x & 0x33333333);
232			x = ((x >> 4) + x) & 0x0f0f0f0f;
233			x *= 0x01010101;
234
235			return x >> 24;
236			}
237
238			/* you have the choice beetween something with a table lookup, */
239			/* something using lots of bit arithmetic and a simple loop */
240			/* we went for the loop */
241			ecb_function_ int ecb_ld32 (uint32_t x) ecb_const;
242			ecb_function_ int ecb_ld32 (uint32_t x)
243			{
244	root	1.3	int r = 0;
245	root	1.2
246	root	1.3	if (x >> 16) { x >>= 16; r += 16; }
247			if (x >> 8) { x >>= 8; r += 8; }
248			if (x >> 4) { x >>= 4; r += 4; }
249			if (x >> 2) { x >>= 2; r += 2; }
250			if (x >> 1) { r += 1; }
251	root	1.2
252			return r;
253			}
254
255			ecb_function_ int ecb_ld64 (uint64_t x) ecb_const;
256			ecb_function_ int ecb_ld64 (uint64_t x)
257			{
258	root	1.3	int r = 0;
259	root	1.2
260	root	1.3	if (x >> 32) { x >>= 32; r += 32; }
261	root	1.1
262	root	1.3	return r + ecb_ld32 (x);
263	root	1.2	}
264			#endif
265	root	1.1
266	root	1.2	/* popcount64 is only available on 64 bit cpus as gcc builtin */
267			/* so for this version we are lazy */
268			ecb_function_ int ecb_popcount64 (uint64_t x) ecb_const;
269			ecb_function_ int
270			ecb_popcount64 (uint64_t x)
271	root	1.1	{
272	root	1.2	return ecb_popcount32 (x) + ecb_popcount32 (x >> 32);
273	root	1.1	}
274
275	root	1.3	ecb_inline uint8_t ecb_rotl8 (uint8_t x, unsigned int count) ecb_const;
276			ecb_inline uint8_t ecb_rotr8 (uint8_t x, unsigned int count) ecb_const;
277			ecb_inline uint16_t ecb_rotl16 (uint16_t x, unsigned int count) ecb_const;
278			ecb_inline uint16_t ecb_rotr16 (uint16_t x, unsigned int count) ecb_const;
279			ecb_inline uint32_t ecb_rotl32 (uint32_t x, unsigned int count) ecb_const;
280			ecb_inline uint32_t ecb_rotr32 (uint32_t x, unsigned int count) ecb_const;
281			ecb_inline uint64_t ecb_rotl64 (uint64_t x, unsigned int count) ecb_const;
282			ecb_inline uint64_t ecb_rotr64 (uint64_t x, unsigned int count) ecb_const;
283
284			ecb_inline uint8_t ecb_rotl8 (uint8_t x, unsigned int count) { return (x >> ( 8 - count)) \| (x << count); }
285			ecb_inline uint8_t ecb_rotr8 (uint8_t x, unsigned int count) { return (x << ( 8 - count)) \| (x >> count); }
286			ecb_inline uint16_t ecb_rotl16 (uint16_t x, unsigned int count) { return (x >> (16 - count)) \| (x << count); }
287			ecb_inline uint16_t ecb_rotr16 (uint16_t x, unsigned int count) { return (x << (16 - count)) \| (x >> count); }
288			ecb_inline uint32_t ecb_rotl32 (uint32_t x, unsigned int count) { return (x >> (32 - count)) \| (x << count); }
289			ecb_inline uint32_t ecb_rotr32 (uint32_t x, unsigned int count) { return (x << (32 - count)) \| (x >> count); }
290			ecb_inline uint64_t ecb_rotl64 (uint64_t x, unsigned int count) { return (x >> (64 - count)) \| (x << count); }
291			ecb_inline uint64_t ecb_rotr64 (uint64_t x, unsigned int count) { return (x << (64 - count)) \| (x >> count); }
292
293	root	1.1	#if ECB_GCC_VERSION(4,3)
294	root	1.2	#define ecb_bswap16(x) (__builtin_bswap32 (x) >> 16)
295			#define ecb_bswap32(x) __builtin_bswap32 (x)
296			#define ecb_bswap64(x) __builtin_bswap64 (x)
297	root	1.1	#else
298	root	1.3	ecb_function_ uint16_t ecb_bswap16 (uint16_t x) ecb_const;
299			ecb_function_ uint16_t
300			ecb_bswap16 (uint16_t x)
301	root	1.2	{
302	root	1.3	return ecb_rotl16 (x, 8);
303	root	1.2	}
304
305			ecb_function_ uint32_t ecb_bswap32 (uint32_t x) ecb_const;
306			ecb_function_ uint32_t
307			ecb_bswap32 (uint32_t x)
308			{
309	root	1.3	return (((uint32_t)ecb_bswap16 (x)) << 16) \| ecb_bswap16 (x >> 16);
310	root	1.2	}
311
312			ecb_function_ uint64_t ecb_bswap64 (uint64_t x) ecb_const;
313			ecb_function_ uint64_t
314			ecb_bswap64 (uint64_t x)
315			{
316	root	1.3	return (((uint64_t)ecb_bswap32 (x)) << 32) \| ecb_bswap32 (x >> 32);
317	root	1.2	}
318	root	1.1	#endif
319
320			#if ECB_GCC_VERSION(4,5)
321	root	1.2	#define ecb_unreachable() __builtin_unreachable ()
322	root	1.1	#else
323	root	1.2	/* this seems to work fine, but gcc always emits a warning for it :/ */
324			ecb_function_ void ecb_unreachable (void) ecb_noreturn;
325			ecb_function_ void ecb_unreachable (void) { }
326	root	1.1	#endif
327
328	root	1.2	/* try to tell the compiler that some condition is definitely true */
329			#define ecb_assume(cond) do { if (!(cond)) ecb_unreachable (); } while (0)
330
331			ecb_function_ unsigned char ecb_byteorder_helper (void) ecb_const;
332			ecb_function_ unsigned char
333	root	1.1	ecb_byteorder_helper (void)
334			{
335			const uint32_t u = 0x11223344;
336			return (unsigned char )&u;
337			}
338
339	root	1.2	ecb_function_ ecb_bool ecb_big_endian (void) ecb_const;
340			ecb_function_ ecb_bool ecb_big_endian (void) { return ecb_byteorder_helper () == 0x11; }
341			ecb_function_ ecb_bool ecb_little_endian (void) ecb_const;
342			ecb_function_ ecb_bool ecb_little_endian (void) { return ecb_byteorder_helper () == 0x44; }
343	root	1.1
344	root	1.2	#if ECB_GCC_VERSION(3,0) \|\| ECB_C99
345			#define ecb_mod(m,n) ((m) % (n) + ((m) % (n) < 0 ? (n) : 0))
346	root	1.1	#else
347	root	1.2	#define ecb_mod(m,n) ((m) < 0 ? ((n) - 1 - ((-1 - (m)) % (n))) : ((m) % (n)))
348	root	1.1	#endif
349
350			#if ecb_cplusplus_does_not_suck
351	root	1.2	/* does not work for local types (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2657.htm) */
352			template<typename T, int N>
353			static inline int ecb_array_length (const T (&arr)[N])
354			{
355			return N;
356			}
357	root	1.1	#else
358	root	1.2	#define ecb_array_length(name) (sizeof (name) / sizeof (name [0]))
359	root	1.1	#endif
360
361			#endif
362