wrong commit, put revision 1.37 back

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@3496 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 2 insertions, 89 deletions

diff --git a/sin.c b/sin.c
index 9b48c7358..b3c40322c 100644
--- a/sin.c
+++ b/sin.c
@@ -128,97 +128,10 @@ mpfr_sin (mpfr_ptr y, mpfr_srcptr x, mp_rnd_t rnd_mode)
 	}
     }
 
-  /* Special case when |x| is very small (and x is a good approximation) */
-  e = MPFR_GET_EXP(x);
-  precy = MPFR_PREC(y);
-  if (e < 0)
-  {
-    long v;
-
-    /*
-    Assume WMLOG that x > 0 (we will compensate for negative x later); then
-    x - x^3 < Sin(x) < x.  Let e be the exponent of x, px be the precision
-    of x and p the precision of y.  Let L and U be such that L < x <= U
-    with L and U "adjacent" representable values in precision p.  (It
-    follows that U = x rounded up to precision p.)
-
-    Then a coarse estimate establishes that if Max(p,px) + 2*e - 2 <= 0
-    then L < Sin(x) < U.  If not rounding to nearest then this is sufficient,
-    otherwise we need to know where it stands with respect to (L+U)/2.  A
-    simple approach is to implicitly use one extra bit so that one of L or U
-    is implicitly replaced by (L+U)/2.  In this case, we require that
-    Max(p+1,px) + 2*e - 2 <= 0.
-    */
-    v = (long)MPFR_PREC(y);
-    if (rnd_mode == GMP_RNDN)
-      v++;
-    if (v < (long)MPFR_PREC(x))
-      v = (long)MPFR_PREC(x);
-    v -= 2;
-    v += (long)e;	/* don't use v += 2*e due to overflow paranoia */
-    if (v > 0)
-      v += (long)e;
-
-    if (v <= 0)		/* small case */
-    {
-      /*
-      If rounding to nearest there is a potential problem if x lies exactly
-      halfway between two representable values: the correct end result is
-      obtained by rounding towards zero in this case.  Since this cannot
-      currently be specified to the setting/rounding routines, an explicit
-      check and change of rounding mode is done in this case.
-      */
-      if (rnd_mode == GMP_RNDN && MPFR_PREC(x) > precy)
-      {
-	mp_limb_t *xp, ok, mask;
-	mp_prec_t sh;
-	int k;
-
-	MPFR_UNSIGNED_MINUS_MODULO(sh, precy);
-	k = MPFR_LIMB_SIZE(x) - MPFR_LIMB_SIZE(y);
-	xp = MPFR_MANT(x) + k;
-	if (MPFR_LIKELY(sh != 0))
-	{
-	  mask = MPFR_LIMB_ONE << (sh - 1);
-	}
-	else
-	{
-	  mask = MPFR_LIMB_HIGHBIT;
-	  xp--;
-	  k--;
-	}
-	ok = (xp[0] & mask) ^ mask;
-	if (ok == 0)
-	{
-	  ok = xp[0] & (mask-1);
-	  if (MPFR_UNLIKELY(ok == 0))
-	  {
-	    while (--k >= 0 && ok == 0)
-	      ok = *--xp;
-	  }
-	}
-
-	if (MPFR_UNLIKELY(ok == 0))		/* problem case */
-	  rnd_mode = GMP_RNDZ;
-      }
-
-      sign = MPFR_INT_SIGN(x);
-      inexact = mpfr_set(y, x, rnd_mode);
-      if (inexact == 0)
-      {
-	inexact = sign;
-	if (MPFR_IS_LIKE_RNDZ(rnd_mode, MPFR_IS_NEG_SIGN(sign)))
-	{
-	  inexact = -inexact;
-	  mpfr_nexttozero(y);
-	}
-      }
-      MPFR_RET(inexact);
-    }
-  }
-
   /* Compute initial precision */
+  precy = MPFR_PREC (y);
   m = precy + MPFR_INT_CEIL_LOG2 (precy) + 13;
+  e = MPFR_GET_EXP (x);
   m += (e < 0) ? -2*e : e;  
 
   sign = mpfr_sin_sign (x);