diff options
Diffstat (limited to 'sysdeps/s390/ffs.c')
-rw-r--r-- | sysdeps/s390/ffs.c | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/sysdeps/s390/ffs.c b/sysdeps/s390/ffs.c new file mode 100644 index 0000000000..048913defb --- /dev/null +++ b/sysdeps/s390/ffs.c @@ -0,0 +1,68 @@ +/* ffs -- find first set bit in a word, counted from least significant end. + S/390 version. + Copyright (C) 2000, 2001 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 Library General Public License as + published by the Free Software Foundation; either version 2 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#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 (x) + 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) +#undef ffsl +weak_alias (__ffs, ffsl) + |