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authorDuncan Wilkie <antigravityd@gmail.com>2023-11-18 06:11:09 -0600
committerDuncan Wilkie <antigravityd@gmail.com>2023-11-18 06:11:09 -0600
commit11da511c784eca003deb90c23570f0873954e0de (patch)
treee14fdd3d5d6345956d67e79ae771d0633d28362b /gmp-6.3.0/mpn/generic/toom_eval_pm2rexp.c
Initial commit.
Diffstat (limited to 'gmp-6.3.0/mpn/generic/toom_eval_pm2rexp.c')
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diff --git a/gmp-6.3.0/mpn/generic/toom_eval_pm2rexp.c b/gmp-6.3.0/mpn/generic/toom_eval_pm2rexp.c
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+/* mpn_toom_eval_pm2rexp -- Evaluate a polynomial in +2^-k and -2^-k
+
+ Contributed to the GNU project by Marco Bodrato
+
+ THE FUNCTION IN THIS FILE IS INTERNAL WITH A MUTABLE INTERFACE. IT IS ONLY
+ SAFE TO REACH IT THROUGH DOCUMENTED INTERFACES. IN FACT, IT IS ALMOST
+ GUARANTEED THAT IT WILL CHANGE OR DISAPPEAR IN A FUTURE GNU MP RELEASE.
+
+Copyright 2009 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 either:
+
+ * the GNU Lesser General Public License as published by the Free
+ Software Foundation; either version 3 of the License, or (at your
+ option) any later version.
+
+or
+
+ * the GNU General Public License as published by the Free Software
+ Foundation; either version 2 of the License, or (at your option) any
+ later version.
+
+or both in parallel, as here.
+
+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 General Public License
+for more details.
+
+You should have received copies of the GNU General Public License and the
+GNU Lesser General Public License along with the GNU MP Library. If not,
+see https://www.gnu.org/licenses/. */
+
+
+#include "gmp-impl.h"
+
+#if HAVE_NATIVE_mpn_addlsh_n
+#define DO_mpn_addlsh_n(dst,src,n,s,ws) mpn_addlsh_n(dst,dst,src,n,s)
+#else
+static mp_limb_t
+DO_mpn_addlsh_n(mp_ptr dst, mp_srcptr src, mp_size_t n, unsigned int s, mp_ptr ws)
+{
+#if USE_MUL_1 && 0
+ return mpn_addmul_1(dst,src,n,CNST_LIMB(1) <<(s));
+#else
+ mp_limb_t __cy;
+ __cy = mpn_lshift(ws,src,n,s);
+ return __cy + mpn_add_n(dst,dst,ws,n);
+#endif
+}
+#endif
+
+/* Evaluates a polynomial of degree k >= 3. */
+int
+mpn_toom_eval_pm2rexp (mp_ptr rp, mp_ptr rm,
+ unsigned int q, mp_srcptr ap, mp_size_t n, mp_size_t t,
+ unsigned int s, mp_ptr ws)
+{
+ unsigned int i;
+ int neg;
+ /* {ap,q*n+t} -> {rp,n+1} {rm,n+1} , with {ws, n+1}*/
+ ASSERT (n >= t);
+ ASSERT (s != 0); /* or _eval_pm1 should be used */
+ ASSERT (q > 1);
+ ASSERT (s*q < GMP_NUMB_BITS);
+ rp[n] = mpn_lshift(rp, ap, n, s*q);
+ ws[n] = mpn_lshift(ws, ap+n, n, s*(q-1));
+ if( (q & 1) != 0) {
+ ASSERT_NOCARRY(mpn_add(ws,ws,n+1,ap+n*q,t));
+ rp[n] += DO_mpn_addlsh_n(rp, ap+n*(q-1), n, s, rm);
+ } else {
+ ASSERT_NOCARRY(mpn_add(rp,rp,n+1,ap+n*q,t));
+ }
+ for(i=2; i<q-1; i++)
+ {
+ rp[n] += DO_mpn_addlsh_n(rp, ap+n*i, n, s*(q-i), rm);
+ i++;
+ ws[n] += DO_mpn_addlsh_n(ws, ap+n*i, n, s*(q-i), rm);
+ };
+
+ neg = (mpn_cmp (rp, ws, n + 1) < 0) ? ~0 : 0;
+
+#if HAVE_NATIVE_mpn_add_n_sub_n
+ if (neg)
+ mpn_add_n_sub_n (rp, rm, ws, rp, n + 1);
+ else
+ mpn_add_n_sub_n (rp, rm, rp, ws, n + 1);
+#else /* !HAVE_NATIVE_mpn_add_n_sub_n */
+ if (neg)
+ mpn_sub_n (rm, ws, rp, n + 1);
+ else
+ mpn_sub_n (rm, rp, ws, n + 1);
+
+ ASSERT_NOCARRY (mpn_add_n (rp, rp, ws, n + 1));
+#endif /* !HAVE_NATIVE_mpn_add_n_sub_n */
+
+ return neg;
+}