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 /* non-lock xchg might be enough */
      #define ECB_MEMORY_FENCE_RELEASE do { } while (0) /* unlikely to change in future cpus */
    #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") /* play safe - not needed in any current cpu */
    #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 /* VC++ 2005 */
    #pragma intrinsic(_ReadBarrier,_WriteBarrier,_ReadWriteBarrier)
    #define ECB_MEMORY_FENCE         _ReadWriteBarrier ()
    #define ECB_MEMORY_FENCE_ACQUIRE _ReadWriteBarrier () /* according to msdn, _ReadBarrier is not a load fence */
    #define ECB_MEMORY_FENCE_RELEASE _WriteBarrier ()
  #elif defined(_WIN32)
    #include <WinNT.h>
    #define ECB_MEMORY_FENCE         MemoryBarrier () /* actually just xchg on x86... scary */
    #define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
    #define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
  #endif
#endif

#ifndef ECB_MEMORY_FENCE
  /*
   * if you get undefined symbol references to pthread_mutex_lock,
   * or failure to find pthread.h, then you should implement
   * the ECB_MEMORY_FENCE operations for your cpu/compiler
   * OR proide pthread.h and link against the posix thread library
   * of your system.
   */
  #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:	1.7
Committed:	Wed Aug 3 15:25:38 2011 UTC (12 years, 9 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.6:	+16 -8 lines
Log Message:	* empty log message *
#	Content
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	#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	#else /* _MSC_VER \|\| __BORLANDC__ */
44	typedef signed __int64 int64_t;
45	typedef unsigned __int64 uint64_t;
46	#endif
47	#else
48	#include <inttypes.h>
49	#endif
50
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	#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	#endif
65
66	/*****************************************************************************/
67
68	#ifndef ECB_MEMORY_FENCE
69	#if ECB_GCC_VERSION(2,5)
70	#if __x86
71	#define ECB_MEMORY_FENCE __asm__ __volatile__ ("lock; orb $0, -1(%%esp)" : : : "memory")
72	#define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE /* non-lock xchg might be enough */
73	#define ECB_MEMORY_FENCE_RELEASE do { } while (0) /* unlikely to change in future cpus */
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") /* play safe - not needed in any current cpu */
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	#elif _MSC_VER >= 1400 /* VC++ 2005 */
88	#pragma intrinsic(_ReadBarrier,_WriteBarrier,_ReadWriteBarrier)
89	#define ECB_MEMORY_FENCE _ReadWriteBarrier ()
90	#define ECB_MEMORY_FENCE_ACQUIRE _ReadWriteBarrier () /* according to msdn, _ReadBarrier is not a load fence */
91	#define ECB_MEMORY_FENCE_RELEASE _WriteBarrier ()
92	#elif defined(_WIN32)
93	#include <WinNT.h>
94	#define ECB_MEMORY_FENCE MemoryBarrier () /* actually just xchg on x86... scary */
95	#define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
96	#define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
97	#endif
98	#endif
99
100	#ifndef ECB_MEMORY_FENCE
101	/*
102	* if you get undefined symbol references to pthread_mutex_lock,
103	* or failure to find pthread.h, then you should implement
104	* the ECB_MEMORY_FENCE operations for your cpu/compiler
105	* OR proide pthread.h and link against the posix thread library
106	* of your system.
107	*/
108	#include <pthread.h>
109
110	static pthread_mutex_t ecb_mf_lock = PTHREAD_MUTEX_INITIALIZER;
111	#define ECB_MEMORY_FENCE do { pthread_mutex_lock (&ecb_mf_lock); pthread_mutex_unlock (&ecb_mf_lock); } while (0)
112	#define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
113	#define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
114	#endif
115
116	/*****************************************************************************/
117
118	#define ECB_C99 (__STDC_VERSION__ >= 199901L)
119
120	#if __cplusplus
121	#define ecb_inline static inline
122	#elif ECB_GCC_VERSION(2,5)
123	#define ecb_inline static __inline__
124	#elif ECB_C99
125	#define ecb_inline static inline
126	#else
127	#define ecb_inline static
128	#endif
129
130	#if ECB_GCC_VERSION(3,3)
131	#define ecb_restrict __restrict__
132	#elif ECB_C99
133	#define ecb_restrict restrict
134	#else
135	#define ecb_restrict
136	#endif
137
138	typedef int ecb_bool;
139
140	#define ECB_CONCAT_(a, b) a ## b
141	#define ECB_CONCAT(a, b) ECB_CONCAT_(a, b)
142	#define ECB_STRINGIFY_(a) # a
143	#define ECB_STRINGIFY(a) ECB_STRINGIFY_(a)
144
145	#define ecb_function_ ecb_inline
146
147	#if ECB_GCC_VERSION(3,1)
148	#define ecb_attribute(attrlist) __attribute__(attrlist)
149	#define ecb_is_constant(expr) __builtin_constant_p (expr)
150	#define ecb_expect(expr,value) __builtin_expect ((expr),(value))
151	#define ecb_prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality)
152	#else
153	#define ecb_attribute(attrlist)
154	#define ecb_is_constant(expr) 0
155	#define ecb_expect(expr,value) (expr)
156	#define ecb_prefetch(addr,rw,locality)
157	#endif
158
159	/* no emulation for ecb_decltype */
160	#if ECB_GCC_VERSION(4,5)
161	#define ecb_decltype(x) __decltype(x)
162	#elif ECB_GCC_VERSION(3,0)
163	#define ecb_decltype(x) __typeof(x)
164	#endif
165
166	#define ecb_noinline ecb_attribute ((__noinline__))
167	#define ecb_noreturn ecb_attribute ((__noreturn__))
168	#define ecb_unused ecb_attribute ((__unused__))
169	#define ecb_const ecb_attribute ((__const__))
170	#define ecb_pure ecb_attribute ((__pure__))
171
172	#if ECB_GCC_VERSION(4,3)
173	#define ecb_artificial ecb_attribute ((__artificial__))
174	#define ecb_hot ecb_attribute ((__hot__))
175	#define ecb_cold ecb_attribute ((__cold__))
176	#else
177	#define ecb_artificial
178	#define ecb_hot
179	#define ecb_cold
180	#endif
181
182	/* put around conditional expressions if you are very sure that the */
183	/* expression is mostly true or mostly false. note that these return */
184	/* booleans, not the expression. */
185	#define ecb_expect_false(expr) ecb_expect (!!(expr), 0)
186	#define ecb_expect_true(expr) ecb_expect (!!(expr), 1)
187	/* for compatibility to the rest of the world */
188	#define ecb_likely(expr) ecb_expect_true (expr)
189	#define ecb_unlikely(expr) ecb_expect_false (expr)
190
191	/* count trailing zero bits and count # of one bits */
192	#if ECB_GCC_VERSION(3,4)
193	/* we assume int == 32 bit, long == 32 or 64 bit and long long == 64 bit */
194	#define ecb_ld32(x) (__builtin_clz (x) ^ 31)
195	#define ecb_ld64(x) (__builtin_clzll (x) ^ 63)
196	#define ecb_ctz32(x) __builtin_ctz (x)
197	#define ecb_ctz64(x) __builtin_ctzll (x)
198	#define ecb_popcount32(x) __builtin_popcount (x)
199	/* no popcountll */
200	#else
201	ecb_function_ int ecb_ctz32 (uint32_t x) ecb_const;
202	ecb_function_ int
203	ecb_ctz32 (uint32_t x)
204	{
205	int r = 0;
206
207	x &= ~x + 1; /* this isolates the lowest bit */
208
209	#if ECB_branchless_on_i386
210	r += !!(x & 0xaaaaaaaa) << 0;
211	r += !!(x & 0xcccccccc) << 1;
212	r += !!(x & 0xf0f0f0f0) << 2;
213	r += !!(x & 0xff00ff00) << 3;
214	r += !!(x & 0xffff0000) << 4;
215	#else
216	if (x & 0xaaaaaaaa) r += 1;
217	if (x & 0xcccccccc) r += 2;
218	if (x & 0xf0f0f0f0) r += 4;
219	if (x & 0xff00ff00) r += 8;
220	if (x & 0xffff0000) r += 16;
221	#endif
222
223	return r;
224	}
225
226	ecb_function_ int ecb_ctz64 (uint64_t x) ecb_const;
227	ecb_function_ int
228	ecb_ctz64 (uint64_t x)
229	{
230	int shift = x & 0xffffffffU ? 0 : 32;
231	return ecb_ctz32 (x >> shift) + shift;
232	}
233
234	ecb_function_ int ecb_popcount32 (uint32_t x) ecb_const;
235	ecb_function_ int
236	ecb_popcount32 (uint32_t x)
237	{
238	x -= (x >> 1) & 0x55555555;
239	x = ((x >> 2) & 0x33333333) + (x & 0x33333333);
240	x = ((x >> 4) + x) & 0x0f0f0f0f;
241	x *= 0x01010101;
242
243	return x >> 24;
244	}
245
246	/* you have the choice beetween something with a table lookup, */
247	/* something using lots of bit arithmetic and a simple loop */
248	/* we went for the loop */
249	ecb_function_ int ecb_ld32 (uint32_t x) ecb_const;
250	ecb_function_ int ecb_ld32 (uint32_t x)
251	{
252	int r = 0;
253
254	if (x >> 16) { x >>= 16; r += 16; }
255	if (x >> 8) { x >>= 8; r += 8; }
256	if (x >> 4) { x >>= 4; r += 4; }
257	if (x >> 2) { x >>= 2; r += 2; }
258	if (x >> 1) { r += 1; }
259
260	return r;
261	}
262
263	ecb_function_ int ecb_ld64 (uint64_t x) ecb_const;
264	ecb_function_ int ecb_ld64 (uint64_t x)
265	{
266	int r = 0;
267
268	if (x >> 32) { x >>= 32; r += 32; }
269
270	return r + ecb_ld32 (x);
271	}
272	#endif
273
274	/* popcount64 is only available on 64 bit cpus as gcc builtin */
275	/* so for this version we are lazy */
276	ecb_function_ int ecb_popcount64 (uint64_t x) ecb_const;
277	ecb_function_ int
278	ecb_popcount64 (uint64_t x)
279	{
280	return ecb_popcount32 (x) + ecb_popcount32 (x >> 32);
281	}
282
283	ecb_inline uint8_t ecb_rotl8 (uint8_t x, unsigned int count) ecb_const;
284	ecb_inline uint8_t ecb_rotr8 (uint8_t x, unsigned int count) ecb_const;
285	ecb_inline uint16_t ecb_rotl16 (uint16_t x, unsigned int count) ecb_const;
286	ecb_inline uint16_t ecb_rotr16 (uint16_t x, unsigned int count) ecb_const;
287	ecb_inline uint32_t ecb_rotl32 (uint32_t x, unsigned int count) ecb_const;
288	ecb_inline uint32_t ecb_rotr32 (uint32_t x, unsigned int count) ecb_const;
289	ecb_inline uint64_t ecb_rotl64 (uint64_t x, unsigned int count) ecb_const;
290	ecb_inline uint64_t ecb_rotr64 (uint64_t x, unsigned int count) ecb_const;
291
292	ecb_inline uint8_t ecb_rotl8 (uint8_t x, unsigned int count) { return (x >> ( 8 - count)) \| (x << count); }
293	ecb_inline uint8_t ecb_rotr8 (uint8_t x, unsigned int count) { return (x << ( 8 - count)) \| (x >> count); }
294	ecb_inline uint16_t ecb_rotl16 (uint16_t x, unsigned int count) { return (x >> (16 - count)) \| (x << count); }
295	ecb_inline uint16_t ecb_rotr16 (uint16_t x, unsigned int count) { return (x << (16 - count)) \| (x >> count); }
296	ecb_inline uint32_t ecb_rotl32 (uint32_t x, unsigned int count) { return (x >> (32 - count)) \| (x << count); }
297	ecb_inline uint32_t ecb_rotr32 (uint32_t x, unsigned int count) { return (x << (32 - count)) \| (x >> count); }
298	ecb_inline uint64_t ecb_rotl64 (uint64_t x, unsigned int count) { return (x >> (64 - count)) \| (x << count); }
299	ecb_inline uint64_t ecb_rotr64 (uint64_t x, unsigned int count) { return (x << (64 - count)) \| (x >> count); }
300
301	#if ECB_GCC_VERSION(4,3)
302	#define ecb_bswap16(x) (__builtin_bswap32 (x) >> 16)
303	#define ecb_bswap32(x) __builtin_bswap32 (x)
304	#define ecb_bswap64(x) __builtin_bswap64 (x)
305	#else
306	ecb_function_ uint16_t ecb_bswap16 (uint16_t x) ecb_const;
307	ecb_function_ uint16_t
308	ecb_bswap16 (uint16_t x)
309	{
310	return ecb_rotl16 (x, 8);
311	}
312
313	ecb_function_ uint32_t ecb_bswap32 (uint32_t x) ecb_const;
314	ecb_function_ uint32_t
315	ecb_bswap32 (uint32_t x)
316	{
317	return (((uint32_t)ecb_bswap16 (x)) << 16) \| ecb_bswap16 (x >> 16);
318	}
319
320	ecb_function_ uint64_t ecb_bswap64 (uint64_t x) ecb_const;
321	ecb_function_ uint64_t
322	ecb_bswap64 (uint64_t x)
323	{
324	return (((uint64_t)ecb_bswap32 (x)) << 32) \| ecb_bswap32 (x >> 32);
325	}
326	#endif
327
328	#if ECB_GCC_VERSION(4,5)
329	#define ecb_unreachable() __builtin_unreachable ()
330	#else
331	/* this seems to work fine, but gcc always emits a warning for it :/ */
332	ecb_function_ void ecb_unreachable (void) ecb_noreturn;
333	ecb_function_ void ecb_unreachable (void) { }
334	#endif
335
336	/* try to tell the compiler that some condition is definitely true */
337	#define ecb_assume(cond) do { if (!(cond)) ecb_unreachable (); } while (0)
338
339	ecb_function_ unsigned char ecb_byteorder_helper (void) ecb_const;
340	ecb_function_ unsigned char
341	ecb_byteorder_helper (void)
342	{
343	const uint32_t u = 0x11223344;
344	return (unsigned char )&u;
345	}
346
347	ecb_function_ ecb_bool ecb_big_endian (void) ecb_const;
348	ecb_function_ ecb_bool ecb_big_endian (void) { return ecb_byteorder_helper () == 0x11; }
349	ecb_function_ ecb_bool ecb_little_endian (void) ecb_const;
350	ecb_function_ ecb_bool ecb_little_endian (void) { return ecb_byteorder_helper () == 0x44; }
351
352	#if ECB_GCC_VERSION(3,0) \|\| ECB_C99
353	#define ecb_mod(m,n) ((m) % (n) + ((m) % (n) < 0 ? (n) : 0))
354	#else
355	#define ecb_mod(m,n) ((m) < 0 ? ((n) - 1 - ((-1 - (m)) % (n))) : ((m) % (n)))
356	#endif
357
358	#if ecb_cplusplus_does_not_suck
359	/* does not work for local types (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2657.htm) */
360	template<typename T, int N>
361	static inline int ecb_array_length (const T (&arr)[N])
362	{
363	return N;
364	}
365	#else
366	#define ecb_array_length(name) (sizeof (name) / sizeof (name [0]))
367	#endif
368
369	#endif
370