/* 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 . */ #include #define ffsl __something_else #include #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