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string: Use builtins for ffs and ffsll

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It allows to remove a lot of arch-specific implementations.

Checked on x86_64, aarch64, powerpc64.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This commit is contained in:
Adhemerval Zanella Netto
2023-08-25 13:30:58 -03:00
committed by Adhemerval Zanella
parent 26d01172f5
commit ae4b8d6a0e
28 changed files with 48 additions and 651 deletions
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6
string/ffs.c
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@ -18,13 +18,16 @@
#include <limits.h>
#define ffsl __something_else
#include <string.h>
#undef ffs
#include <math-use-builtins.h>
/* Find the first bit set in I. */
int
__ffs (int i)
{
#if USE_FFS_BUILTIN
return __builtin_ffs (i);
#else
static const unsigned char table[] =
{
0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
@ -42,6 +45,7 @@ __ffs (int i)
a = x <= 0xffff ? (x <= 0xff ? 0 : 8) : (x <= 0xffffff ? 16 : 24);
return table[x >> a] + a;
#endif
}
weak_alias (__ffs, ffs)
libc_hidden_def (__ffs)