Clean up code.

Add generic ZivLoop controller.


git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@3305 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 33 insertions, 30 deletions

diff --git a/pow_si.c b/pow_si.c
index 8e2ccfa2a..fc4cd3f26 100644
--- a/pow_si.c
+++ b/pow_si.c
@@ -35,7 +35,7 @@ mpfr_pow_si (mpfr_ptr y, mpfr_srcptr x, long int n, mp_rnd_t rnd_mode)
     return mpfr_pow_ui (y, x, n, rnd_mode);
   else
     {
-      if (MPFR_UNLIKELY( MPFR_IS_SINGULAR(x) ))
+      if (MPFR_UNLIKELY (MPFR_IS_SINGULAR (x)))
 	{
 	  if (MPFR_IS_NAN (x))
 	    {
@@ -53,7 +53,7 @@ mpfr_pow_si (mpfr_ptr y, mpfr_srcptr x, long int n, mp_rnd_t rnd_mode)
 	    }
 	  else /* x is zero */
 	    {
-              MPFR_ASSERTD (MPFR_IS_ZERO(x));
+              MPFR_ASSERTD (MPFR_IS_ZERO (x));
 	      MPFR_SET_INF(y);
 	      if (MPFR_IS_POS (x) || ((unsigned) n & 1) == 0)
 		MPFR_SET_POS (y);
@@ -62,7 +62,7 @@ mpfr_pow_si (mpfr_ptr y, mpfr_srcptr x, long int n, mp_rnd_t rnd_mode)
 	      MPFR_RET(0);
 	    }
 	}
-      MPFR_CLEAR_FLAGS(y);
+      MPFR_CLEAR_FLAGS (y);
 
       /* detect exact powers: x^(-n) is exact iff x is a power of 2 */
       if (mpfr_cmp_si_2exp (x, MPFR_SIGN(x), MPFR_EXP(x) - 1) == 0)
@@ -73,13 +73,13 @@ mpfr_pow_si (mpfr_ptr y, mpfr_srcptr x, long int n, mp_rnd_t rnd_mode)
 	  expx --;
 	  MPFR_ASSERTD (n < 0);
 	  /* Warning n*expx may overflow! 
-	     Many systems abort with LONG_MIN / 1 or LONG_MIN/-1*/
+	     Some systems abort with LONG_MIN / 1 or LONG_MIN/-1*/
 	  if (n != -1 && expx > 0 && -expx < MPFR_EXP_MIN / (-n))
 	    MPFR_EXP (y) = MPFR_EMIN_MIN - 1; /* Underflow */
 	  else if (n != -1 && expx < 0 && -expx > MPFR_EXP_MAX / (-n))
 	    MPFR_EXP (y) = MPFR_EMAX_MAX + 1; /* Overflow */
           else
-	    MPFR_EXP(y) += n * expx;
+	    MPFR_EXP (y) += n * expx;
           return mpfr_check_range (y, 0, rnd_mode);
         }
 
@@ -89,18 +89,17 @@ mpfr_pow_si (mpfr_ptr y, mpfr_srcptr x, long int n, mp_rnd_t rnd_mode)
       {
         /* Declaration of the intermediary variable */
         mpfr_t t;
-
         /* Declaration of the size variable */
-        mp_prec_t Nx = MPFR_PREC(x);   /* Precision of input variable */
-        mp_prec_t Ny = MPFR_PREC(y);   /* Precision of output variable */
-
-        mp_prec_t Nt;   /* Precision of the intermediary variable */
-        long int err;   /* Precision of error */
+        mp_prec_t Nx = MPFR_PREC (x);   /* Precision of input variable */
+        mp_prec_t Ny = MPFR_PREC (y);   /* Precision of output variable */
+        mp_prec_t Nt;         /* Precision of the intermediary variable */
+        mp_exp_t  err;                            /* Precision of error */
         int inexact;
 	MPFR_SAVE_EXPO_DECL (expo);
+	MPFR_ZIV_DECL (loop);
 
         /* compute the precision of intermediary variable */
-        Nt = MAX(Nx,Ny);
+        Nt = MAX (Nx, Ny);
         /* the optimal number of bits : see algorithms.ps */
         Nt = Nt + 3 + MPFR_INT_CEIL_LOG2 (Nt);
 
@@ -108,24 +107,28 @@ mpfr_pow_si (mpfr_ptr y, mpfr_srcptr x, long int n, mp_rnd_t rnd_mode)
 
         /* initialise of intermediary	variable */
         mpfr_init2 (t, Nt);
-
-        do {
-	  /* reactualisation of the precision */
-	  mpfr_set_prec (t, Nt);
-	  
-	  /* compute 1/(x^n) n>0*/
-	  mpfr_pow_ui (t, x, (unsigned long int) n, GMP_RNDN);
-	  inexact = MPFR_IS_ZERO (t) || MPFR_IS_INF (t);
-	  mpfr_ui_div (t, 1, t, GMP_RNDN);
-	  inexact = inexact || MPFR_IS_ZERO (t) || MPFR_IS_INF (t);
-	  /* error estimate -- see pow function in algorithms.ps */
-	  err = Nt - 3;
-	  
-	  /* actualisation of the precision */
-	  Nt += BITS_PER_MP_LIMB;
-	} while (inexact == 0 &&
-		 !mpfr_can_round (t, err, GMP_RNDN, GMP_RNDZ,
-				  Ny + (rnd_mode == GMP_RNDN)));
+	
+	MPFR_ZIV_INIT (loop, Nt);
+        for (;;)
+	  {
+	    /* compute 1/(x^n) n>0*/
+	    mpfr_pow_ui (t, x, (unsigned long int) n, GMP_RNDN);
+	    inexact = MPFR_IS_ZERO (t) || MPFR_IS_INF (t);
+	    mpfr_ui_div (t, 1, t, GMP_RNDN);
+	    inexact = inexact || MPFR_IS_ZERO (t) || MPFR_IS_INF (t);
+
+	    /* error estimate -- see pow function in algorithms.ps */
+	    err = Nt - 3;
+	    if (MPFR_LIKELY (inexact != 0
+			     || mpfr_can_round (t, err, GMP_RNDN, GMP_RNDZ,
+						Ny + (rnd_mode == GMP_RNDN))))
+	      break;
+
+	    /* actualisation of the precision */
+	    Nt += BITS_PER_MP_LIMB;
+	    mpfr_set_prec (t, Nt);
+	  }
+	MPFR_ZIV_FREE (loop);
 
         inexact = mpfr_set (y, t, rnd_mode);
         mpfr_clear (t);