[project @ 1998-06-05 14:38:00 by simonm]

Initial revision

ghc/rts/gmp/mpz/configure.in

+# This file is a shell script fragment that supplies the information
+# necessary for a configure script to process the program in
+# this directory.  For more information, look at ../configure.
+
+configdirs=tests
+srctrigger=add_ui.c
+srcname="GNU Multi-Precision library/mpz"
+
+# per-host:
+
+# per-target:
+

ghc/rts/gmp/mpz/dmincl.c

+/* dmincl.c -- include file for tdiv_qr.c, tdiv_r.c.
+
+Copyright (C) 1991, 1993, 1994, 1996 Free Software Foundation, Inc.
+
+This file is part of the GNU MP Library.
+
+The GNU MP Library is free software; you can redistribute it and/or modify
+it under the terms of the GNU Library General Public License as published by
+the Free Software Foundation; either version 2 of the License, or (at your
+option) any later version.
+
+The GNU MP Library is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
+License for more details.
+
+You should have received a copy of the GNU Library General Public License
+along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+MA 02111-1307, USA. */
+
+/* If den == quot, den needs temporary storage.
+   If den == rem, den needs temporary storage.
+   If num == quot, num needs temporary storage.
+   If den has temporary storage, it can be normalized while being copied,
+     i.e no extra storage should be allocated.  */
+
+/* This is the function body of mdiv, mpz_divmod, and mpz_mod.
+
+   If COMPUTE_QUOTIENT is defined, the quotient is put in the MP_INT
+   object quot, otherwise that variable is not referenced at all.
+
+   The remainder is always computed, and the result is put in the MP_INT
+   object rem.  */
+
+{
+  mp_ptr np, dp;
+  mp_ptr qp, rp;
+  mp_size_t nsize = num->_mp_size;
+  mp_size_t dsize = den->_mp_size;
+  mp_size_t qsize, rsize;
+  mp_size_t sign_remainder = nsize;
+#ifdef COMPUTE_QUOTIENT
+  mp_size_t sign_quotient = nsize ^ dsize;
+#endif
+  unsigned normalization_steps;
+  mp_limb_t q_limb;
+  TMP_DECL (marker);
+
+  nsize = ABS (nsize);
+  dsize = ABS (dsize);
+
+  /* Ensure space is enough for quotient and remainder. */
+
+  /* We need space for an extra limb in the remainder, because it's
+     up-shifted (normalized) below.  */
+  rsize = nsize + 1;
+  if (rem->_mp_alloc < rsize)
+    _mpz_realloc (rem, rsize);
+
+  qsize = rsize - dsize;	/* qsize cannot be bigger than this.  */
+  if (qsize <= 0)
+    {
+      if (num != rem)
+	{
+	  rem->_mp_size = num->_mp_size;
+	  MPN_COPY (rem->_mp_d, num->_mp_d, nsize);
+	}
+#ifdef COMPUTE_QUOTIENT
+      /* This needs to follow the assignment to rem, in case the
+	 numerator and quotient are the same.  */
+      quot->_mp_size = 0;
+#endif
+      return;
+    }
+
+#ifdef COMPUTE_QUOTIENT
+  if (quot->_mp_alloc < qsize)
+    _mpz_realloc (quot, qsize);
+#endif
+
+  /* Read pointers here, when reallocation is finished.  */
+  np = num->_mp_d;
+  dp = den->_mp_d;
+  rp = rem->_mp_d;
+
+  /* Optimize division by a single-limb divisor.  */
+  if (dsize == 1)
+    {
+      mp_limb_t rlimb;
+#ifdef COMPUTE_QUOTIENT
+      qp = quot->_mp_d;
+      rlimb = mpn_divmod_1 (qp, np, nsize, dp[0]);
+      qsize -= qp[qsize - 1] == 0;
+      quot->_mp_size = sign_quotient >= 0 ? qsize : -qsize;
+#else
+      rlimb = mpn_mod_1 (np, nsize, dp[0]);
+#endif
+      rp[0] = rlimb;
+      rsize = rlimb != 0;
+      rem->_mp_size = sign_remainder >= 0 ? rsize : -rsize;
+      return;
+    }
+
+  TMP_MARK (marker);
+
+#ifdef COMPUTE_QUOTIENT
+  qp = quot->_mp_d;
+
+  /* Make sure QP and NP point to different objects.  Otherwise the
+     numerator would be gradually overwritten by the quotient limbs.  */
+  if (qp == np)
+    {
+      /* Copy NP object to temporary space.  */
+      np = (mp_ptr) TMP_ALLOC (nsize * BYTES_PER_MP_LIMB);
+      MPN_COPY (np, qp, nsize);
+    }
+
+#else
+  /* Put quotient at top of remainder. */
+  qp = rp + dsize;
+#endif
+
+  count_leading_zeros (normalization_steps, dp[dsize - 1]);
+
+  /* Normalize the denominator, i.e. make its most significant bit set by
+     shifting it NORMALIZATION_STEPS bits to the left.  Also shift the
+     numerator the same number of steps (to keep the quotient the same!).  */
+  if (normalization_steps != 0)
+    {
+      mp_ptr tp;
+      mp_limb_t nlimb;
+
+      /* Shift up the denominator setting the most significant bit of
+	 the most significant word.  Use temporary storage not to clobber
+	 the original contents of the denominator.  */
+      tp = (mp_ptr) TMP_ALLOC (dsize * BYTES_PER_MP_LIMB);
+      mpn_lshift (tp, dp, dsize, normalization_steps);
+      dp = tp;
+
+      /* Shift up the numerator, possibly introducing a new most
+	 significant word.  Move the shifted numerator in the remainder
+	 meanwhile.  */
+      nlimb = mpn_lshift (rp, np, nsize, normalization_steps);
+      if (nlimb != 0)
+	{
+	  rp[nsize] = nlimb;
+	  rsize = nsize + 1;
+	}
+      else
+	rsize = nsize;
+    }
+  else
+    {
+      /* The denominator is already normalized, as required.  Copy it to
+	 temporary space if it overlaps with the quotient or remainder.  */
+#ifdef COMPUTE_QUOTIENT
+      if (dp == rp || dp == qp)
+#else
+      if (dp == rp)
+#endif
+	{
+	  mp_ptr tp;
+
+	  tp = (mp_ptr) TMP_ALLOC (dsize * BYTES_PER_MP_LIMB);
+	  MPN_COPY (tp, dp, dsize);
+	  dp = tp;
+	}
+
+      /* Move the numerator to the remainder.  */
+      if (rp != np)
+	MPN_COPY (rp, np, nsize);
+
+      rsize = nsize;
+    }
+
+  q_limb = mpn_divmod (qp, rp, rsize, dp, dsize);
+
+#ifdef COMPUTE_QUOTIENT
+  qsize = rsize - dsize;
+  if (q_limb)
+    {
+      qp[qsize] = q_limb;
+      qsize += 1;
+    }
+
+  quot->_mp_size = sign_quotient >= 0 ? qsize : -qsize;
+#endif
+
+  rsize = dsize;
+  MPN_NORMALIZE (rp, rsize);
+
+  if (normalization_steps != 0 && rsize != 0)
+    {
+      mpn_rshift (rp, rp, rsize, normalization_steps);
+      rsize -= rp[rsize - 1] == 0;
+    }
+
+  rem->_mp_size = sign_remainder >= 0 ? rsize : -rsize;
+  TMP_FREE (marker);
+}