Moved the mpfr_mpn_exp function to a new file "mpn_exp.c" as it is

used by both "get_str.c" and "set_str.c".


git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@2631 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 0 insertions, 132 deletions

diff --git a/get_str.c b/get_str.c
index 7672f233f..229350526 100644
--- a/get_str.c
+++ b/get_str.c
@@ -183,138 +183,6 @@ _mpfr_ceil (double x)
   return ((y < x) ? y + 1.0 : y);
 }
 
-/* this function computes an approximation of b^e in {a, n}, with exponent
-   stored in exp_r. The computed value is rounded towards zero (truncated).
-   It returns an integer f such that the final error is bounded by 2^f ulps,
-   that is:
-   a*2^exp_r <= b^e <= 2^exp_r (a + 2^f),
-   where a represents {a, n}, i.e. the integer 
-   a[0] + a[1]*B + ... + a[n-1]*B^(n-1) where B=2^BITS_PER_MP_LIMB */
-long
-mpfr_mpn_exp (mp_limb_t *a, mp_exp_t *exp_r, int b, mp_exp_t e, size_t n)
-{
-  mp_limb_t *c, B;
-  mp_exp_t f, h;
-  int i;
-  unsigned long t; /* number of bits in e */
-  unsigned long bits;
-  size_t n1;
-  unsigned int erreur;           /* (number - 1) of loop a^2b inexact */
-                                 /* erreur == t meens no error */
-  int err_s_a2 = 0;
-  int err_s_ab = 0;              /* number of error when shift A^2, AB */
-  TMP_DECL(marker);
-
-  MPFR_ASSERTN(e > 0);
-  MPFR_ASSERTN((2 <= b) && (b <= 36));
-
-  TMP_MARK(marker);
-
-  /* initialization of a, b, f, h */
-
-  /* normalize the base */
-  B = (mp_limb_t) b;
-  count_leading_zeros (h, B);
-
-  bits = BITS_PER_MP_LIMB - h;
-
-  B = B << h;
-  h = - h;
-
-  /* allocate space for A and set it to B */
-  c = (mp_limb_t*) TMP_ALLOC(2 * n * BYTES_PER_MP_LIMB);
-  a [n - 1] = B;
-  MPN_ZERO (a, n - 1);
-  /* initial exponent for A: invariant is A = {a, n} * 2^f */
-  f = h - (n - 1) * BITS_PER_MP_LIMB;
-
-  /* determine number of bits in e */
-  count_leading_zeros (t, (mp_limb_t) e);
-
-  t = BITS_PER_MP_LIMB - t; /* number of bits of exponent e */
-
-  erreur = t;
-
-  MPN_ZERO (c, 2 * n);
-
-  for (i = t - 2; i >= 0; i--)
-    {
-
-      /* determine precision needed */
-      bits = n * BITS_PER_MP_LIMB - mpn_scan1 (a, 0);
-      n1 = (n * BITS_PER_MP_LIMB - bits) / BITS_PER_MP_LIMB;
-
-      /* square of A : {c+2n1, 2(n-n1)} = {a+n1, n-n1}^2 */
-      mpn_sqr_n (c + 2 * n1, a + n1, n - n1);
-
-      /* set {c+n, 2n1-n} to 0 : {c, n} = {a, n}^2*K^n */
-
-      f = 2 * f + n * BITS_PER_MP_LIMB;
-      if ((c[2*n - 1] & MPFR_LIMB_HIGHBIT) == 0)
-	{
-	  /* shift A by one bit to the left */
-	  mpn_lshift (a, c + n, n, 1);
-	  a[0] |= mpn_lshift (c + n - 1, c + n - 1, 1, 1);
-	  f --;
-	  if (erreur != t)
-	    err_s_a2 ++;
-	}
-      else
-	MPN_COPY (a, c + n, n);
-
-      if ((erreur == t) && (2 * n1 <= n) &&
-	  (mpn_scan1 (c + 2 * n1, 0) < (n - 2 * n1) * BITS_PER_MP_LIMB))
-	erreur = i;
-
-      if (e & (1 << i))
-	{
-	  /* multiply A by B */
-	  c[2 * n - 1] = mpn_mul_1 (c + n - 1, a, n, B);
-	  f += h + BITS_PER_MP_LIMB;
-	  if ((c[2 * n - 1] & MPFR_LIMB_HIGHBIT) == 0)
-	    { /* shift A by one bit to the left */
-	      mpn_lshift (a, c + n, n, 1);
-	      a[0] |= mpn_lshift (c + n - 1, c + n - 1, 1, 1);
-	      f --;
-	    }
-	  else
-	    {
-	      MPN_COPY (a, c + n, n);
-	      if (erreur != t)
-		err_s_ab ++;
-	    }
-	  if ((erreur == t) && (c[n - 1] != 0))
-            erreur = i;
-	  
-	}
-    }
-
-  TMP_FREE(marker);
-
-  *exp_r = f;  
-
-  if (erreur == t)
-    return -1; /* exact */
-  else
-    {
-      /* if there are p loops after the first inexact result, with
-	 j shifts in a^2 and l shifts in a*b, then the final error is
-	 at most 2^(p+ceil((j+1)/2)+l+1)*ulp(res).
-         This is bounded by 2^(5/2*t-1/2) where t is the number of bits of e.
-      */
-      erreur = erreur + err_s_ab + err_s_a2 / 2 + 3;
-      if ((erreur - 1) >= ((n * BITS_PER_MP_LIMB - 1) / 2))
-	erreur = n * BITS_PER_MP_LIMB; /* completely wrong: this is very
-                                        unlikely to happen since erreur is
-                                       at most 5/2*log_2(e), and 
-                                       n * BITS_PER_MP_LIMB is at least
-                                       3*log_2(e) */
-    }
-
-  return erreur;  
-}
-
-
 /* Input: an approximation r*2^f of an real Y, with |r*2^f-Y| <= 2^(e+f).
    Returns if possible in the string s the mantissa corresponding to 
    the integer nearest to Y, within the direction rnd, and returns the