--- /dev/null
+/* 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);
+}
projects / ghc-hetmet.git / blobdiff