trunk/js/jsbit.h

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla Communicator client code, released
 * March 31, 1998.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1998
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#ifndef jsbit_h___
#define jsbit_h___

#include "jstypes.h"
#include "jsutil.h"

JS_BEGIN_EXTERN_C

/*
** A jsbitmap_t is a long integer that can be used for bitmaps
*/
typedef JSUword     jsbitmap_t;     /* NSPR name, a la Unix system types */
typedef jsbitmap_t  jsbitmap;       /* JS-style scalar typedef name */

#define JS_BITMAP_SIZE(bits)    (JS_HOWMANY(bits, JS_BITS_PER_WORD) *         \
                                 sizeof(jsbitmap))

#define JS_TEST_BIT(_map,_bit)  ((_map)[(_bit)>>JS_BITS_PER_WORD_LOG2] &      \
                                 ((jsbitmap)1<<((_bit)&(JS_BITS_PER_WORD-1))))
#define JS_SET_BIT(_map,_bit)   ((_map)[(_bit)>>JS_BITS_PER_WORD_LOG2] |=     \
                                 ((jsbitmap)1<<((_bit)&(JS_BITS_PER_WORD-1))))
#define JS_CLEAR_BIT(_map,_bit) ((_map)[(_bit)>>JS_BITS_PER_WORD_LOG2] &=     \
                                 ~((jsbitmap)1<<((_bit)&(JS_BITS_PER_WORD-1))))

/*
** Compute the log of the least power of 2 greater than or equal to n
*/
extern JS_PUBLIC_API(JSIntn) JS_CeilingLog2(JSUint32 i);

/*
** Compute the log of the greatest power of 2 less than or equal to n
*/
extern JS_PUBLIC_API(JSIntn) JS_FloorLog2(JSUint32 i);

/*
 * Replace bit-scanning code sequences with CPU-specific instructions to
 * speedup calculations of ceiling/floor log2.
 *
 * With GCC 3.4 or later we can use __builtin_clz for that, see bug 327129.
 *
 * SWS: Added MSVC intrinsic bitscan support.  See bugs 349364 and 356856.
 */
#if defined(_WIN32) && (_MSC_VER >= 1300) && defined(_M_IX86)

unsigned char _BitScanForward(unsigned long * Index, unsigned long Mask);
unsigned char _BitScanReverse(unsigned long * Index, unsigned long Mask);
# pragma intrinsic(_BitScanForward,_BitScanReverse)

__forceinline static int
__BitScanForward32(unsigned int val)
{
    unsigned long idx;

    _BitScanForward(&idx, (unsigned long)val);
    return (int)idx;
}
__forceinline static int
__BitScanReverse32(unsigned int val)
{
    unsigned long idx;

    _BitScanReverse(&idx, (unsigned long)val);
    return (int)(31-idx);
}
# define js_bitscan_ctz32(val)  __BitScanForward32(val)
# define js_bitscan_clz32(val)  __BitScanReverse32(val)
# define JS_HAS_BUILTIN_BITSCAN32

#elif (__GNUC__ >= 4) || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)

# define js_bitscan_ctz32(val)  __builtin_ctz(val)
# define js_bitscan_clz32(val)  __builtin_clz(val)
# define JS_HAS_BUILTIN_BITSCAN32
# if (JS_BYTES_PER_WORD == 8)
#  define js_bitscan_ctz64(val)  __builtin_ctzll(val)
#  define js_bitscan_clz64(val)  __builtin_clzll(val)
#  define JS_HAS_BUILTIN_BITSCAN64
# endif

#endif

/*
** Macro version of JS_CeilingLog2: Compute the log of the least power of
** 2 greater than or equal to _n. The result is returned in _log2.
*/
#ifdef JS_HAS_BUILTIN_BITSCAN32
/*
 * Use intrinsic function or count-leading-zeros to calculate ceil(log2(_n)).
 * The macro checks for "n <= 1" and not "n != 0" as js_bitscan_clz32(0) is
 * undefined.
 */
# define JS_CEILING_LOG2(_log2,_n)                                            \
    JS_BEGIN_MACRO                                                            \
        JS_STATIC_ASSERT(sizeof(unsigned int) == sizeof(JSUint32));           \
        unsigned int j_ = (unsigned int)(_n);                                 \
        (_log2) = (j_ <= 1 ? 0 : 32 - js_bitscan_clz32(j_ - 1));              \
    JS_END_MACRO
#else
# define JS_CEILING_LOG2(_log2,_n)                                            \
    JS_BEGIN_MACRO                                                            \
        JSUint32 j_ = (JSUint32)(_n);                                         \
        (_log2) = 0;                                                          \
        if ((j_) & ((j_)-1))                                                  \
            (_log2) += 1;                                                     \
        if ((j_) >> 16)                                                       \
            (_log2) += 16, (j_) >>= 16;                                       \
        if ((j_) >> 8)                                                        \
            (_log2) += 8, (j_) >>= 8;                                         \
        if ((j_) >> 4)                                                        \
            (_log2) += 4, (j_) >>= 4;                                         \
        if ((j_) >> 2)                                                        \
            (_log2) += 2, (j_) >>= 2;                                         \
        if ((j_) >> 1)                                                        \
            (_log2) += 1;                                                     \
    JS_END_MACRO
#endif

/*
** Macro version of JS_FloorLog2: Compute the log of the greatest power of
** 2 less than or equal to _n. The result is returned in _log2.
**
** This is equivalent to finding the highest set bit in the word.
*/
#ifdef JS_HAS_BUILTIN_BITSCAN32
/*
 * Use js_bitscan_clz32 or count-leading-zeros to calculate floor(log2(_n)).
 * Since js_bitscan_clz32(0) is undefined, the macro set the loweset bit to 1
 * to ensure 0 result when _n == 0.
 */
# define JS_FLOOR_LOG2(_log2,_n)                                              \
    JS_BEGIN_MACRO                                                            \
        JS_STATIC_ASSERT(sizeof(unsigned int) == sizeof(JSUint32));           \
        (_log2) = 31 - js_bitscan_clz32(((unsigned int)(_n)) | 1);            \
    JS_END_MACRO
#else
# define JS_FLOOR_LOG2(_log2,_n)                                              \
    JS_BEGIN_MACRO                                                            \
        JSUint32 j_ = (JSUint32)(_n);                                         \
        (_log2) = 0;                                                          \
        if ((j_) >> 16)                                                       \
            (_log2) += 16, (j_) >>= 16;                                       \
        if ((j_) >> 8)                                                        \
            (_log2) += 8, (j_) >>= 8;                                         \
        if ((j_) >> 4)                                                        \
            (_log2) += 4, (j_) >>= 4;                                         \
        if ((j_) >> 2)                                                        \
            (_log2) += 2, (j_) >>= 2;                                         \
        if ((j_) >> 1)                                                        \
            (_log2) += 1;                                                     \
    JS_END_MACRO
#endif

/*
 * Internal function.
 * Compute the log of the least power of 2 greater than or equal to n.
 * This is a version of JS_CeilingLog2 that operates on jsuword with
 * CPU-dependant size.
 */
#define JS_CEILING_LOG2W(n) ((n) <= 1 ? 0 : 1 + JS_FLOOR_LOG2W((n) - 1))

/*
 * Internal function.
 * Compute the log of the greatest power of 2 less than or equal to n.
 * This is a version of JS_FloorLog2 that operates on jsuword with
 * CPU-dependant size and requires that n != 0.
 */
#define JS_FLOOR_LOG2W(n) (JS_ASSERT((n) != 0), js_FloorLog2wImpl(n))

#if JS_BYTES_PER_WORD == 4

# ifdef JS_HAS_BUILTIN_BITSCAN32
JS_STATIC_ASSERT(sizeof(unsigned) == sizeof(JSUword));
#  define js_FloorLog2wImpl(n)                                                \
    ((JSUword)(JS_BITS_PER_WORD - 1 - js_bitscan_clz32(n)))
# else
#  define js_FloorLog2wImpl(n) ((JSUword)JS_FloorLog2(n))
#endif

#elif JS_BYTES_PER_WORD == 8

# ifdef JS_HAS_BUILTIN_BITSCAN64
JS_STATIC_ASSERT(sizeof(unsigned long long) == sizeof(JSUword));
#  define js_FloorLog2wImpl(n)                                                \
    ((JSUword)(JS_BITS_PER_WORD - 1 - js_bitscan_clz64(n)))
# else
extern JSUword js_FloorLog2wImpl(JSUword n);
# endif

#else

# error "NOT SUPPORTED"

#endif

/*
 * Macros for rotate left. There is no rotate operation in the C Language so
 * the construct (a << 4) | (a >> 28) is used instead. Most compilers convert
 * this to a rotate instruction but some versions of MSVC don't without a
 * little help.  To get MSVC to generate a rotate instruction, we have to use
 * the _rotl intrinsic and use a pragma to make _rotl inline.
 *
 * MSVC in VS2005 will do an inline rotate instruction on the above construct.
 */

#if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_AMD64) || \
    defined(_M_X64))
#include <stdlib.h>
#pragma intrinsic(_rotl)
#define JS_ROTATE_LEFT32(a, bits) _rotl(a, bits)
#else
#define JS_ROTATE_LEFT32(a, bits) (((a) << (bits)) | ((a) >> (32 - (bits))))
#endif

JS_END_EXTERN_C
#endif /* jsbit_h___ */
1	/* -- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -- */
2	/* *** BEGIN LICENSE BLOCK ***
3	* Version: MPL 1.1/GPL 2.0/LGPL 2.1
4	*
5	* The contents of this file are subject to the Mozilla Public License Version
6	* 1.1 (the "License"); you may not use this file except in compliance with
7	* the License. You may obtain a copy of the License at
8	* http://www.mozilla.org/MPL/
9	*
10	* Software distributed under the License is distributed on an "AS IS" basis,
11	* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
12	* for the specific language governing rights and limitations under the
13	* License.
14	*
15	* The Original Code is Mozilla Communicator client code, released
16	* March 31, 1998.
17	*
18	* The Initial Developer of the Original Code is
19	* Netscape Communications Corporation.
20	* Portions created by the Initial Developer are Copyright (C) 1998
21	* the Initial Developer. All Rights Reserved.
22	*
23	* Contributor(s):
24	*
25	* Alternatively, the contents of this file may be used under the terms of
26	* either of the GNU General Public License Version 2 or later (the "GPL"),
27	* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
28	* in which case the provisions of the GPL or the LGPL are applicable instead
29	* of those above. If you wish to allow use of your version of this file only
30	* under the terms of either the GPL or the LGPL, and not to allow others to
31	* use your version of this file under the terms of the MPL, indicate your
32	* decision by deleting the provisions above and replace them with the notice
33	* and other provisions required by the GPL or the LGPL. If you do not delete
34	* the provisions above, a recipient may use your version of this file under
35	* the terms of any one of the MPL, the GPL or the LGPL.
36	*
37	* *** END LICENSE BLOCK *** */
38
39	#ifndef jsbit_h___
40	#define jsbit_h___
41
42	#include "jstypes.h"
43	#include "jsutil.h"
44
45	JS_BEGIN_EXTERN_C
46
47	/*
48	** A jsbitmap_t is a long integer that can be used for bitmaps
49	*/
50	typedef JSUword jsbitmap_t; /* NSPR name, a la Unix system types */
51	typedef jsbitmap_t jsbitmap; /* JS-style scalar typedef name */
52
53	#define JS_BITMAP_SIZE(bits) (JS_HOWMANY(bits, JS_BITS_PER_WORD) * \
54	sizeof(jsbitmap))
55
56	#define JS_TEST_BIT(_map,_bit) ((_map)[(_bit)>>JS_BITS_PER_WORD_LOG2] & \
57	((jsbitmap)1<<((_bit)&(JS_BITS_PER_WORD-1))))
58	#define JS_SET_BIT(_map,_bit) ((_map)[(_bit)>>JS_BITS_PER_WORD_LOG2] \|= \
59	((jsbitmap)1<<((_bit)&(JS_BITS_PER_WORD-1))))
60	#define JS_CLEAR_BIT(_map,_bit) ((_map)[(_bit)>>JS_BITS_PER_WORD_LOG2] &= \
61	~((jsbitmap)1<<((_bit)&(JS_BITS_PER_WORD-1))))
62
63	/*
64	** Compute the log of the least power of 2 greater than or equal to n
65	*/
66	extern JS_PUBLIC_API(JSIntn) JS_CeilingLog2(JSUint32 i);
67
68	/*
69	** Compute the log of the greatest power of 2 less than or equal to n
70	*/
71	extern JS_PUBLIC_API(JSIntn) JS_FloorLog2(JSUint32 i);
72
73	/*
74	* Replace bit-scanning code sequences with CPU-specific instructions to
75	* speedup calculations of ceiling/floor log2.
76	*
77	* With GCC 3.4 or later we can use __builtin_clz for that, see bug 327129.
78	*
79	* SWS: Added MSVC intrinsic bitscan support. See bugs 349364 and 356856.
80	*/
81	#if defined(_WIN32) && (_MSC_VER >= 1300) && defined(_M_IX86)
82
83	unsigned char _BitScanForward(unsigned long * Index, unsigned long Mask);
84	unsigned char _BitScanReverse(unsigned long * Index, unsigned long Mask);
85	# pragma intrinsic(_BitScanForward,_BitScanReverse)
86
87	__forceinline static int
88	__BitScanForward32(unsigned int val)
89	{
90	unsigned long idx;
91
92	_BitScanForward(&idx, (unsigned long)val);
93	return (int)idx;
94	}
95	__forceinline static int
96	__BitScanReverse32(unsigned int val)
97	{
98	unsigned long idx;
99
100	_BitScanReverse(&idx, (unsigned long)val);
101	return (int)(31-idx);
102	}
103	# define js_bitscan_ctz32(val) __BitScanForward32(val)
104	# define js_bitscan_clz32(val) __BitScanReverse32(val)
105	# define JS_HAS_BUILTIN_BITSCAN32
106
107	#elif (__GNUC__ >= 4) \|\| (__GNUC__ == 3 && __GNUC_MINOR__ >= 4)
108
109	# define js_bitscan_ctz32(val) __builtin_ctz(val)
110	# define js_bitscan_clz32(val) __builtin_clz(val)
111	# define JS_HAS_BUILTIN_BITSCAN32
112	# if (JS_BYTES_PER_WORD == 8)
113	# define js_bitscan_ctz64(val) __builtin_ctzll(val)
114	# define js_bitscan_clz64(val) __builtin_clzll(val)
115	# define JS_HAS_BUILTIN_BITSCAN64
116	# endif
117
118	#endif
119
120	/*
121	** Macro version of JS_CeilingLog2: Compute the log of the least power of
122	** 2 greater than or equal to _n. The result is returned in _log2.
123	*/
124	#ifdef JS_HAS_BUILTIN_BITSCAN32
125	/*
126	* Use intrinsic function or count-leading-zeros to calculate ceil(log2(_n)).
127	* The macro checks for "n <= 1" and not "n != 0" as js_bitscan_clz32(0) is
128	* undefined.
129	*/
130	# define JS_CEILING_LOG2(_log2,_n) \
131	JS_BEGIN_MACRO \
132	JS_STATIC_ASSERT(sizeof(unsigned int) == sizeof(JSUint32)); \
133	unsigned int j_ = (unsigned int)(_n); \
134	(_log2) = (j_ <= 1 ? 0 : 32 - js_bitscan_clz32(j_ - 1)); \
135	JS_END_MACRO
136	#else
137	# define JS_CEILING_LOG2(_log2,_n) \
138	JS_BEGIN_MACRO \
139	JSUint32 j_ = (JSUint32)(_n); \
140	(_log2) = 0; \
141	if ((j_) & ((j_)-1)) \
142	(_log2) += 1; \
143	if ((j_) >> 16) \
144	(_log2) += 16, (j_) >>= 16; \
145	if ((j_) >> 8) \
146	(_log2) += 8, (j_) >>= 8; \
147	if ((j_) >> 4) \
148	(_log2) += 4, (j_) >>= 4; \
149	if ((j_) >> 2) \
150	(_log2) += 2, (j_) >>= 2; \
151	if ((j_) >> 1) \
152	(_log2) += 1; \
153	JS_END_MACRO
154	#endif
155
156	/*
157	** Macro version of JS_FloorLog2: Compute the log of the greatest power of
158	** 2 less than or equal to _n. The result is returned in _log2.
159	**
160	** This is equivalent to finding the highest set bit in the word.
161	*/
162	#ifdef JS_HAS_BUILTIN_BITSCAN32
163	/*
164	* Use js_bitscan_clz32 or count-leading-zeros to calculate floor(log2(_n)).
165	* Since js_bitscan_clz32(0) is undefined, the macro set the loweset bit to 1
166	* to ensure 0 result when _n == 0.
167	*/
168	# define JS_FLOOR_LOG2(_log2,_n) \
169	JS_BEGIN_MACRO \
170	JS_STATIC_ASSERT(sizeof(unsigned int) == sizeof(JSUint32)); \
171	(_log2) = 31 - js_bitscan_clz32(((unsigned int)(_n)) \| 1); \
172	JS_END_MACRO
173	#else
174	# define JS_FLOOR_LOG2(_log2,_n) \
175	JS_BEGIN_MACRO \
176	JSUint32 j_ = (JSUint32)(_n); \
177	(_log2) = 0; \
178	if ((j_) >> 16) \
179	(_log2) += 16, (j_) >>= 16; \
180	if ((j_) >> 8) \
181	(_log2) += 8, (j_) >>= 8; \
182	if ((j_) >> 4) \
183	(_log2) += 4, (j_) >>= 4; \
184	if ((j_) >> 2) \
185	(_log2) += 2, (j_) >>= 2; \
186	if ((j_) >> 1) \
187	(_log2) += 1; \
188	JS_END_MACRO
189	#endif
190
191	/*
192	* Internal function.
193	* Compute the log of the least power of 2 greater than or equal to n.
194	* This is a version of JS_CeilingLog2 that operates on jsuword with
195	* CPU-dependant size.
196	*/
197	#define JS_CEILING_LOG2W(n) ((n) <= 1 ? 0 : 1 + JS_FLOOR_LOG2W((n) - 1))
198
199	/*
200	* Internal function.
201	* Compute the log of the greatest power of 2 less than or equal to n.
202	* This is a version of JS_FloorLog2 that operates on jsuword with
203	* CPU-dependant size and requires that n != 0.
204	*/
205	#define JS_FLOOR_LOG2W(n) (JS_ASSERT((n) != 0), js_FloorLog2wImpl(n))
206
207	#if JS_BYTES_PER_WORD == 4
208
209	# ifdef JS_HAS_BUILTIN_BITSCAN32
210	JS_STATIC_ASSERT(sizeof(unsigned) == sizeof(JSUword));
211	# define js_FloorLog2wImpl(n) \
212	((JSUword)(JS_BITS_PER_WORD - 1 - js_bitscan_clz32(n)))
213	# else
214	# define js_FloorLog2wImpl(n) ((JSUword)JS_FloorLog2(n))
215	#endif
216
217	#elif JS_BYTES_PER_WORD == 8
218
219	# ifdef JS_HAS_BUILTIN_BITSCAN64
220	JS_STATIC_ASSERT(sizeof(unsigned long long) == sizeof(JSUword));
221	# define js_FloorLog2wImpl(n) \
222	((JSUword)(JS_BITS_PER_WORD - 1 - js_bitscan_clz64(n)))
223	# else
224	extern JSUword js_FloorLog2wImpl(JSUword n);
225	# endif
226
227	#else
228
229	# error "NOT SUPPORTED"
230
231	#endif
232
233	/*
234	* Macros for rotate left. There is no rotate operation in the C Language so
235	* the construct (a << 4) \| (a >> 28) is used instead. Most compilers convert
236	* this to a rotate instruction but some versions of MSVC don't without a
237	* little help. To get MSVC to generate a rotate instruction, we have to use
238	* the _rotl intrinsic and use a pragma to make _rotl inline.
239	*
240	* MSVC in VS2005 will do an inline rotate instruction on the above construct.
241	*/
242
243	#if defined(_MSC_VER) && (defined(_M_IX86) \|\| defined(_M_AMD64) \|\| \
244	defined(_M_X64))
245	#include <stdlib.h>
246	#pragma intrinsic(_rotl)
247	#define JS_ROTATE_LEFT32(a, bits) _rotl(a, bits)
248	#else
249	#define JS_ROTATE_LEFT32(a, bits) (((a) << (bits)) \| ((a) >> (32 - (bits))))
250	#endif
251
252	JS_END_EXTERN_C
253	#endif /* jsbit_h___ */