[src/exp_2.c] export (internally) nbits_ulong (renamed to mpfr_nbits_ulong)

[src/mpfr-impl.h] added prototype for mpfr_nbits_ulong
[src/pow_si.c] fixed for 16-bit limb


git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@13140 280ebfd0-de03-0410-8827-d642c229c3f4

3 files changed, 14 insertions, 6 deletions

diff --git a/src/exp_2.c b/src/exp_2.c
index 316b3d555..cc1c5f3c0 100644
--- a/src/exp_2.c
+++ b/src/exp_2.c
@@ -21,7 +21,9 @@ along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
 http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
 
+#ifdef MPFR_LONG_WITHIN_LIMB
 #define MPFR_NEED_LONGLONG_H /* for count_leading_zeros */
+#endif
 #include "mpfr-impl.h"
 
 static unsigned long
@@ -35,9 +37,14 @@ mpz_normalize2 (mpz_t, mpz_t, mpfr_exp_t, mpfr_exp_t);
 
 /* count the number of significant bits of n, i.e.,
    nbits(unsigned long) - count_leading_zeros (n) */
-static int
-nbits_ulong (unsigned long n)
+int
+mpfr_nbits_ulong (unsigned long n)
 {
+#ifdef MPFR_LONG_WITHIN_LIMB
+  int cnt;
+  count_leading_zeros (cnt, (mp_limb_t) n);
+  return GMP_NUMB_BITS - cnt;
+#else  
   int nbits = 0;
 
   MPFR_ASSERTD (n > 0);
@@ -67,6 +74,7 @@ nbits_ulong (unsigned long n)
   MPFR_ASSERTD (n <= 3);
   /* now n = 1, 2, or 3 */
   return nbits + 1 + (n >= 2);
+#endif  
 }
 
 /* if k = the number of bits of z > q, divides z by 2^(k-q) and returns k-q.
@@ -182,7 +190,7 @@ mpfr_exp_2 (mpfr_ptr y, mpfr_srcptr x, mpfr_rnd_t rnd_mode)
     error_r = 0;
   else
     {
-      error_r = nbits_ulong (SAFE_ABS (unsigned long, n) + 1);
+      error_r = mpfr_nbits_ulong (SAFE_ABS (unsigned long, n) + 1);
       /* we have |x| <= 2^error_r * log(2) */
     }
 
diff --git a/src/mpfr-impl.h b/src/mpfr-impl.h
index b24975491..131e53a29 100644
--- a/src/mpfr-impl.h
+++ b/src/mpfr-impl.h
@@ -2359,6 +2359,8 @@ __MPFR_DECLSPEC void mpfr_mpz_clear (mpz_ptr);
 
 __MPFR_DECLSPEC int mpfr_odd_p (mpfr_srcptr);
 
+__MPFR_DECLSPEC int mpfr_nbits_ulong (unsigned long);  
+
 #ifdef _MPFR_H_HAVE_VA_LIST
 /* Declared only if <stdarg.h> has been included. */
 __MPFR_DECLSPEC int mpfr_vasnprintf_aux (char**, char*, size_t, const char*,
diff --git a/src/pow_si.c b/src/pow_si.c
index a4f0ea8f5..22c17547b 100644
--- a/src/pow_si.c
+++ b/src/pow_si.c
@@ -20,7 +20,6 @@ along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
 http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
 
-#define MPFR_NEED_LONGLONG_H
 #include "mpfr-impl.h"
 
 /* The computation of y = pow_si(x,n) is done by
@@ -149,8 +148,7 @@ mpfr_pow_si (mpfr_ptr y, mpfr_srcptr x, long int n, mpfr_rnd_t rnd)
         MPFR_ZIV_DECL (loop);
 
         abs_n = - (unsigned long) n;
-        count_leading_zeros (size_n, (mp_limb_t) abs_n);
-        size_n = GMP_NUMB_BITS - size_n;
+        size_n = mpfr_nbits_ulong (abs_n);
 
         /* initial working precision */
         Ny = MPFR_PREC (y);