| /* ffs -- find first set bit in a word, counted from least significant end. |
| S/390 version. |
| Copyright (C) 2000-2016 Free Software Foundation, Inc. |
| Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com). |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <limits.h> |
| #define ffsl __something_else |
| #include <string.h> |
| |
| #undef ffs |
| |
| /* ffs: find first bit set. This is defined the same way as |
| the libc and compiler builtin ffs routines, therefore |
| differs in spirit from the above ffz (man ffs). */ |
| |
| int |
| __ffs (int x) |
| { |
| int r; |
| |
| if (x == 0) |
| return 0; |
| __asm__(" lr %%r1,%1\n" |
| " sr %0,%0\n" |
| " tml %%r1,0xFFFF\n" |
| " jnz 0f\n" |
| " ahi %0,16\n" |
| " srl %%r1,16\n" |
| "0: tml %%r1,0x00FF\n" |
| " jnz 1f\n" |
| " ahi %0,8\n" |
| " srl %%r1,8\n" |
| "1: tml %%r1,0x000F\n" |
| " jnz 2f\n" |
| " ahi %0,4\n" |
| " srl %%r1,4\n" |
| "2: tml %%r1,0x0003\n" |
| " jnz 3f\n" |
| " ahi %0,2\n" |
| " srl %%r1,2\n" |
| "3: tml %%r1,0x0001\n" |
| " jnz 4f\n" |
| " ahi %0,1\n" |
| "4:" |
| : "=&d" (r) : "d" (x) : "cc", "1" ); |
| return r+1; |
| } |
| |
| weak_alias (__ffs, ffs) |
| libc_hidden_def (__ffs) |
| libc_hidden_builtin_def (ffs) |
| #if ULONG_MAX == UINT_MAX |
| #undef ffsl |
| weak_alias (__ffs, ffsl) |
| #endif |