unified is_power_of_two() and mpfr_powerof2_raw()

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@10756 280ebfd0-de03-0410-8827-d642c229c3f4

3 files changed, 10 insertions, 19 deletions

diff --git a/src/mpfr-impl.h b/src/mpfr-impl.h
index 2b3c6be26..ee6c73e5f 100644
--- a/src/mpfr-impl.h
+++ b/src/mpfr-impl.h
@@ -2080,6 +2080,7 @@ __MPFR_DECLSPEC mpfr_exp_t mpfr_ceil_mul (mpfr_exp_t, int, int);
 __MPFR_DECLSPEC int mpfr_exp_2 (mpfr_ptr, mpfr_srcptr,mpfr_rnd_t);
 __MPFR_DECLSPEC int mpfr_exp_3 (mpfr_ptr, mpfr_srcptr,mpfr_rnd_t);
 __MPFR_DECLSPEC int mpfr_powerof2_raw (mpfr_srcptr);
+__MPFR_DECLSPEC int mpfr_powerof2_raw2 (const mp_limb_t *, mp_size_t);
 
 __MPFR_DECLSPEC int mpfr_pow_general (mpfr_ptr, mpfr_srcptr,
                            mpfr_srcptr, mpfr_rnd_t, int, mpfr_save_expo_t *);
diff --git a/src/powerof2.c b/src/powerof2.c
index f10ace0ad..53f0551cd 100644
--- a/src/powerof2.c
+++ b/src/powerof2.c
@@ -31,16 +31,17 @@ http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
 int
 mpfr_powerof2_raw (mpfr_srcptr x)
 {
-  mp_limb_t *xp;
-  mp_size_t xn;
-
   /* This is an internal function, and we may call it with some
      wrong numbers (ie good mantissa but wrong flags or exp)
      So we don't want to test if it is a pure FP.
      MPFR_ASSERTN(MPFR_IS_PURE_FP(x)); */
-  xp = MPFR_MANT(x);
-  xn = (MPFR_PREC(x) - 1) / GMP_NUMB_BITS;
-  if (xp[xn] != MPFR_LIMB_HIGHBIT)
+  return mpfr_powerof2_raw2 (MPFR_MANT(x), MPFR_LIMB_SIZE(x));
+}
+
+int
+mpfr_powerof2_raw2 (const mp_limb_t *xp, mp_size_t xn)
+{
+  if (xp[--xn] != MPFR_LIMB_HIGHBIT)
     return 0;
   while (xn > 0)
     if (xp[--xn] != 0)
diff --git a/src/round_prec.c b/src/round_prec.c
index 4f835d9cc..7f7127722 100644
--- a/src/round_prec.c
+++ b/src/round_prec.c
@@ -140,17 +140,6 @@ mpfr_can_round (mpfr_srcptr b, mpfr_exp_t err, mpfr_rnd_t rnd1,
                                MPFR_SIGN(b), err, rnd1, rnd2, prec);
 }
 
-static int
-is_power_of_two (const mp_limb_t *bp, mp_size_t bn)
-{
-  if (bp[--bn] != MPFR_LIMB_HIGHBIT)
-    return 0;
-  while (bn--)
-    if (bp[bn] != 0)
-      return 0;
-  return 1;
-}
-
 /* TODO: mpfr_can_round_raw currently does a memory allocation and some
    mpn operations. A bit inspection like for mpfr_round_p (round_p.c) may
    be sufficient, though this would be more complex than the one done in
@@ -230,7 +219,7 @@ mpfr_can_round_raw (const mp_limb_t *bp, mp_size_t bn, int neg, mpfr_exp_t err,
         {
           if (rnd1 != MPFR_RNDZ &&
               err == prec + 1 &&
-              is_power_of_two (bp, bn))
+              mpfr_powerof2_raw2 (bp, bn))
             return 0;
           else
             return 1;
@@ -253,7 +242,7 @@ mpfr_can_round_raw (const mp_limb_t *bp, mp_size_t bn, int neg, mpfr_exp_t err,
          RNDN RNDZ no
          RNDN RNDA no
          RNDN RNDN ok except when err = prec + 1 */
-      if (is_power_of_two (bp, bn))
+      if (mpfr_powerof2_raw2 (bp, bn))
         {
           if ((rnd2 == MPFR_RNDZ || rnd2 == MPFR_RNDA) && rnd1 != rnd2)
             return 0;