[src] Add constants:

  * __gmpfr_mone = -1
  * mpfr_const_log2_RNDD = log(2) rounded down in precision 64 bits
  * mpfr_const_log2_RNDU = log(2) rounded up in precision 64 bits
(modified patch from Patrick Pélissier).

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@8913 280ebfd0-de03-0410-8827-d642c229c3f4

7 files changed, 53 insertions, 19 deletions

diff --git a/src/constant.c b/src/constant.c
index 0599ef7fa..87eabf7c5 100644
--- a/src/constant.c
+++ b/src/constant.c
@@ -26,3 +26,40 @@ static const mp_limb_t __gmpfr_limb1[1] = {MPFR_LIMB_HIGHBIT};
 const mpfr_t __gmpfr_one = {{2, MPFR_SIGN_POS, 1, (mp_limb_t*)__gmpfr_limb1}};
 const mpfr_t __gmpfr_two = {{2, MPFR_SIGN_POS, 2, (mp_limb_t*)__gmpfr_limb1}};
 const mpfr_t __gmpfr_four ={{2, MPFR_SIGN_POS, 3, (mp_limb_t*)__gmpfr_limb1}};
+const mpfr_t __gmpfr_mone ={{2, MPFR_SIGN_NEG, 1, (mp_limb_t*)__gmpfr_limb1}};
+
+#if 0
+#elif GMP_NUMB_BITS == 16
+static const mp_limb_t mpfr_l2_dd__tab[] = { 0x79ab, 0xd1cf, 0x17f7, 0xb172 };
+#elif GMP_NUMB_BITS == 32
+static const mp_limb_t mpfr_l2_dd__tab[] = { 0xd1cf79ab, 0xb17217f7};
+#elif GMP_NUMB_BITS == 64
+static const mp_limb_t mpfr_l2_dd__tab[] = { 0xb17217f7d1cf79ab };
+#elif GMP_NUMB_BITS == 96
+static const mp_limb_t mpfr_l2_dd__tab[] = { 0xb17217f7d1cf79ab00000000 };
+#elif GMP_NUMB_BITS == 128
+static const mp_limb_t mpfr_l2_dd__tab[] = { 0xb17217f7d1cf79ab0000000000000000 };
+#elif GMP_NUMB_BITS == 256
+static const mp_limb_t mpfr_l2_dd__tab[] = { 0xb17217f7d1cf79ab000000000000000000000000000000000000000000000000 };
+#endif
+
+const mpfr_t __gmpfr_const_log2_RNDD =
+  {{64, MPFR_SIGN_POS, 0, (mp_limb_t*)mpfr_l2_dd__tab}};
+
+#if 0
+#elif GMP_NUMB_BITS == 16
+static const mp_limb_t mpfr_l2_du__tab[] = { 0x79ac, 0xd1cf, 0x17f7, 0xb172 };
+#elif GMP_NUMB_BITS == 32
+static const mp_limb_t mpfr_l2_du__tab[] = { 0xd1cf79ac, 0xb17217f7};
+#elif GMP_NUMB_BITS == 64
+static const mp_limb_t mpfr_l2_du__tab[] = { 0xb17217f7d1cf79ac };
+#elif GMP_NUMB_BITS == 96
+static const mp_limb_t mpfr_l2_du__tab[] = { 0xb17217f7d1cf79ac00000000 };
+#elif GMP_NUMB_BITS == 128
+static const mp_limb_t mpfr_l2_du__tab[] = { 0xb17217f7d1cf79ac0000000000000000 };
+#elif GMP_NUMB_BITS == 256
+static const mp_limb_t mpfr_l2_du__tab[] = { 0xb17217f7d1cf79ac000000000000000000000000000000000000000000000000 };
+#endif
+
+const mpfr_t __gmpfr_const_log2_RNDU =
+  {{64, MPFR_SIGN_POS, 0, (mp_limb_t*)mpfr_l2_du__tab}};
diff --git a/src/eint.c b/src/eint.c
index 9ee948e75..6da7af331 100644
--- a/src/eint.c
+++ b/src/eint.c
@@ -244,8 +244,7 @@ mpfr_eint (mpfr_ptr y, mpfr_srcptr x, mpfr_rnd_t rnd)
   mpfr_init2 (ump, 64);
   mpfr_log (tmp, x, MPFR_RNDU);
   mpfr_sub (ump, x, tmp, MPFR_RNDD);
-  mpfr_const_log2 (tmp, MPFR_RNDU);
-  mpfr_div (ump, ump, tmp, MPFR_RNDD);
+  mpfr_div (ump, ump, __gmpfr_const_log2_RNDU, MPFR_RNDD);
   /* FIXME: We really need mpfr_set_exp_t and mpfr_cmpfr_exp_t functions. */
   MPFR_ASSERTN (MPFR_EMAX_MAX <= LONG_MAX);
   if (mpfr_cmp_ui (ump, __gmpfr_emax) >= 0)
diff --git a/src/erf.c b/src/erf.c
index 3eba8e6a6..724d3a0f2 100644
--- a/src/erf.c
+++ b/src/erf.c
@@ -110,9 +110,8 @@ mpfr_erf (mpfr_ptr y, mpfr_srcptr x, mpfr_rnd_t rnd_mode)
     }
 
   MPFR_TMP_INIT1(xf_limb, xf, 53);
-  mpfr_const_log2 (xf, MPFR_RNDU);
-  mpfr_div (xf, x, xf, MPFR_RNDZ); /* round to zero ensures we get a lower
-                                     bound of |x/log(2)| */
+  mpfr_div (xf, x, __gmpfr_const_log2_RNDU, MPFR_RNDZ); /* round to zero
+                        ensures we get a lower bound of |x/log(2)| */
   mpfr_mul (xf, xf, x, MPFR_RNDZ);
   large = mpfr_cmp_ui (xf, MPFR_PREC (y) + 1) > 0;
 
diff --git a/src/exp.c b/src/exp.c
index f5a43a18d..902f59165 100644
--- a/src/exp.c
+++ b/src/exp.c
@@ -86,8 +86,9 @@ mpfr_exp (mpfr_ptr y, mpfr_srcptr x, mpfr_rnd_t rnd_mode)
 
       inexact = mpfr_set_exp_t (e, expo.saved_emax, MPFR_RNDN);
       MPFR_ASSERTD (inexact == 0);
-      mpfr_const_log2 (bound_emax, expo.saved_emax < 0 ? MPFR_RNDD : MPFR_RNDU);
-      mpfr_mul (bound_emax, bound_emax, e, MPFR_RNDU);
+      mpfr_mul (bound_emax, expo.saved_emax < 0 ?
+                __gmpfr_const_log2_RNDD : __gmpfr_const_log2_RNDU,
+                e, MPFR_RNDU);
       previous_emax = expo.saved_emax;
       MPFR_SAVE_EXPO_FREE (expo);
     }
diff --git a/src/exp_2.c b/src/exp_2.c
index 5dade2a9a..247f1a960 100644
--- a/src/exp_2.c
+++ b/src/exp_2.c
@@ -106,8 +106,7 @@ mpfr_exp_2 (mpfr_ptr y, mpfr_srcptr x, mpfr_rnd_t rnd_mode)
     {
       mp_limb_t r_limb[(sizeof (long) -1) / sizeof(mp_limb_t) + 1];
       MPFR_TMP_INIT1(r_limb, r, sizeof (long) * CHAR_BIT);
-      mpfr_const_log2 (r, MPFR_RNDZ);
-      mpfr_div (r, x, r, MPFR_RNDN);
+      mpfr_div (r, x, __gmpfr_const_log2_RNDD, MPFR_RNDN);
       n = mpfr_get_si (r, MPFR_RNDN);
     }
   /* we have |x| <= (|n|+1)*log(2) */
diff --git a/src/expm1.c b/src/expm1.c
index a855dfee3..e3cd64b2d 100644
--- a/src/expm1.c
+++ b/src/expm1.c
@@ -82,14 +82,12 @@ mpfr_expm1 (mpfr_ptr y, mpfr_srcptr x , mpfr_rnd_t rnd_mode)
 
   if (MPFR_IS_NEG (x) && ex > 5)  /* x <= -32 */
     {
-      mpfr_t minus_one, t;
+      mp_limb_t t_limb[(64 - 1) / GMP_NUMB_BITS + 1];
+      mpfr_t t;
       mpfr_exp_t err;
 
-      mpfr_init2 (minus_one, 2);
-      mpfr_init2 (t, 64);
-      mpfr_set_si (minus_one, -1, MPFR_RNDN);
-      mpfr_const_log2 (t, MPFR_RNDU); /* round upward since x is negative */
-      mpfr_div (t, x, t, MPFR_RNDU); /* > x / ln(2) */
+      MPFR_TMP_INIT1(t_limb, t, 64);
+      mpfr_div (t, x, __gmpfr_const_log2_RNDU, MPFR_RNDU); /* > x / ln(2) */
       err = mpfr_cmp_si (t, MPFR_EMIN_MIN >= -LONG_MAX ?
                          MPFR_EMIN_MIN : -LONG_MAX) <= 0 ?
         - (MPFR_EMIN_MIN >= -LONG_MAX ? MPFR_EMIN_MIN : -LONG_MAX) :
@@ -97,10 +95,8 @@ mpfr_expm1 (mpfr_ptr y, mpfr_srcptr x , mpfr_rnd_t rnd_mode)
       /* exp(x) = 2^(x/ln(2))
                <= 2^max(MPFR_EMIN_MIN,-LONG_MAX,ceil(x/ln(2)+epsilon))
          with epsilon > 0 */
-      mpfr_clear (t);
-      MPFR_SMALL_INPUT_AFTER_SAVE_EXPO (y, minus_one, err, 0, 0, rnd_mode,
-                                        expo, { mpfr_clear (minus_one); });
-      mpfr_clear (minus_one);
+      MPFR_SMALL_INPUT_AFTER_SAVE_EXPO (y, __gmpfr_mone, err, 0, 0,
+                                        rnd_mode, expo, {});
     }
 
   /* General case */
diff --git a/src/mpfr-impl.h b/src/mpfr-impl.h
index 77ea752f6..569bb8336 100644
--- a/src/mpfr-impl.h
+++ b/src/mpfr-impl.h
@@ -249,6 +249,9 @@ __MPFR_DECLSPEC extern const __mpfr_struct __gmpfr_l2b[BASE_MAX-1][2];
 __MPFR_DECLSPEC extern const mpfr_t __gmpfr_one;
 __MPFR_DECLSPEC extern const mpfr_t __gmpfr_two;
 __MPFR_DECLSPEC extern const mpfr_t __gmpfr_four;
+__MPFR_DECLSPEC extern const mpfr_t __gmpfr_mone;
+__MPFR_DECLSPEC extern const mpfr_t __gmpfr_const_log2_RNDD;
+__MPFR_DECLSPEC extern const mpfr_t __gmpfr_const_log2_RNDU;
 
 
 #if defined (__cplusplus)