1 /* ----------------------------------------------------------------------- *
3 * Copyright 1996-2010 The NASM Authors - All Rights Reserved
4 * See the file AUTHORS included with the NASM distribution for
5 * the specific copyright holders.
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following
11 * * Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * * Redistributions in binary form must reproduce the above
14 * copyright notice, this list of conditions and the following
15 * disclaimer in the documentation and/or other materials provided
16 * with the distribution.
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
19 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
20 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
21 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
22 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
23 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
26 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
29 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
30 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 * ----------------------------------------------------------------------- */
37 #if defined(__GNUC__) && defined(__x86_64__)
39 int ilog2_32(uint32_t v
)
43 __asm__("bsrl %1,%0 ; cmovel %2,%0"
45 : "rm" (v
), "rm" (0));
49 #elif defined(__GNUC__) && defined(__i386__)
51 int ilog2_32(uint32_t v
)
55 __asm__("bsrl %1,%0 ; jnz 1f ; xorl %0,%0\n"
62 #elif defined(HAVE_GNUC_4)
64 int ilog2_32(uint32_t v
)
69 return __builtin_clz(v
) ^ 31;
74 int ilog2_32(uint32_t v
)
104 #if defined(__GNUC__) && defined(__x86_64__)
106 int ilog2_64(uint64_t v
)
110 __asm__("bsrq %1,%0 ; cmoveq %2,%0"
112 : "rm" (v
), "rm" (UINT64_C(0)));
116 #elif defined(HAVE_GNUC_4)
118 int ilog2_64(uint64_t v
)
123 return __builtin_clzll(v
) ^ 63;
128 int ilog2_64(uint64_t vv
)
133 if ((v
= vv
>> 32) != 0) {
138 if (v
& 0xffff0000) {
165 * v == 0 ? 0 : is_power2(x) ? ilog2_X(v) : -1
167 int alignlog2_32(uint32_t v
)
169 if (unlikely(v
& (v
-1)))
170 return -1; /* invalid alignment */
175 int alignlog2_64(uint64_t v
)
177 if (unlikely(v
& (v
-1)))
178 return -1; /* invalid alignment */