| 0,0 → 1,94 |
|---|
| /* |
| * Copyright (C) 2006 Ondrej Palkovsky |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - 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. |
| * - The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, 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 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| /** @addtogroup generic |
| * @{ |
| */ |
| /** @file |
| */ |
| |
| #ifndef LIBC_BITOPS_H_ |
| #define LIBC_BITOPS_H_ |
| |
| #include <types.h> |
| |
| |
| /** Return position of first non-zero bit from left (i.e. [log_2(arg)]). |
| * |
| * If number is zero, it returns 0 |
| */ |
| static inline int fnzb32(uint32_t arg) |
| { |
| int n = 0; |
| |
| if (arg >> 16) { |
| arg >>= 16; |
| n += 16; |
| } |
| |
| if (arg >> 8) { |
| arg >>= 8; |
| n += 8; |
| } |
| |
| if (arg >> 4) { |
| arg >>= 4; |
| n += 4; |
| } |
| |
| if (arg >> 2) { |
| arg >>= 2; |
| n += 2; |
| } |
| |
| if (arg >> 1) { |
| arg >>= 1; |
| n += 1; |
| } |
| |
| return n; |
| } |
| |
| static inline int fnzb64(uint64_t arg) |
| { |
| int n = 0; |
| |
| if (arg >> 32) { |
| arg >>= 32; |
| n += 32; |
| } |
| |
| return n + fnzb32((uint32_t) arg); |
| } |
| |
| #define fnzb(x) fnzb32(x) |
| |
| #endif |
| |
| /** @} |
| */ |