From 11da511c784eca003deb90c23570f0873954e0de Mon Sep 17 00:00:00 2001
From: Duncan Wilkie <antigravityd@gmail.com>
Date: Sat, 18 Nov 2023 06:11:09 -0600
Subject: Initial commit.

---
 gmp-6.3.0/mpn/generic/toom_eval_pm2.c | 130 ++++++++++++++++++++++++++++++++++
 1 file changed, 130 insertions(+)
 create mode 100644 gmp-6.3.0/mpn/generic/toom_eval_pm2.c

(limited to 'gmp-6.3.0/mpn/generic/toom_eval_pm2.c')

diff --git a/gmp-6.3.0/mpn/generic/toom_eval_pm2.c b/gmp-6.3.0/mpn/generic/toom_eval_pm2.c
new file mode 100644
index 0000000..be682c7
--- /dev/null
+++ b/gmp-6.3.0/mpn/generic/toom_eval_pm2.c
@@ -0,0 +1,130 @@
+/* mpn_toom_eval_pm2 -- Evaluate a polynomial in +2 and -2
+
+   Contributed to the GNU project by Niels Möller and 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"
+
+/* DO_addlsh2(d,a,b,n,cy) computes cy,{d,n} <- {a,n} + 4*(cy,{b,n}), it
+   can be used as DO_addlsh2(d,a,d,n,d[n]), for accumulation on {d,n+1}. */
+#if HAVE_NATIVE_mpn_addlsh2_n
+#define DO_addlsh2(d, a, b, n, cy)	\
+do {					\
+  (cy) <<= 2;				\
+  (cy) += mpn_addlsh2_n(d, a, b, n);	\
+} while (0)
+#else
+#if HAVE_NATIVE_mpn_addlsh_n
+#define DO_addlsh2(d, a, b, n, cy)	\
+do {					\
+  (cy) <<= 2;				\
+  (cy) += mpn_addlsh_n(d, a, b, n, 2);	\
+} while (0)
+#else
+/* The following is not a general substitute for addlsh2.
+   It is correct if d == b, but it is not if d == a.  */
+#define DO_addlsh2(d, a, b, n, cy)	\
+do {					\
+  (cy) <<= 2;				\
+  (cy) += mpn_lshift(d, b, n, 2);	\
+  (cy) += mpn_add_n(d, d, a, n);	\
+} while (0)
+#endif
+#endif
+
+/* Evaluates a polynomial of degree 2 < k < GMP_NUMB_BITS, in the
+   points +2 and -2. */
+int
+mpn_toom_eval_pm2 (mp_ptr xp2, mp_ptr xm2, unsigned k,
+		   mp_srcptr xp, mp_size_t n, mp_size_t hn, mp_ptr tp)
+{
+  int i;
+  int neg;
+  mp_limb_t cy;
+
+  ASSERT (k >= 3);
+  ASSERT (k < GMP_NUMB_BITS);
+
+  ASSERT (hn > 0);
+  ASSERT (hn <= n);
+
+  /* The degree k is also the number of full-size coefficients, so
+   * that last coefficient, of size hn, starts at xp + k*n. */
+
+  cy = 0;
+  DO_addlsh2 (xp2, xp + (k-2) * n, xp + k * n, hn, cy);
+  if (hn != n)
+    cy = mpn_add_1 (xp2 + hn, xp + (k-2) * n + hn, n - hn, cy);
+  for (i = k - 4; i >= 0; i -= 2)
+    DO_addlsh2 (xp2, xp + i * n, xp2, n, cy);
+  xp2[n] = cy;
+
+  k--;
+
+  cy = 0;
+  DO_addlsh2 (tp, xp + (k-2) * n, xp + k * n, n, cy);
+  for (i = k - 4; i >= 0; i -= 2)
+    DO_addlsh2 (tp, xp + i * n, tp, n, cy);
+  tp[n] = cy;
+
+  if (k & 1)
+    ASSERT_NOCARRY(mpn_lshift (tp , tp , n + 1, 1));
+  else
+    ASSERT_NOCARRY(mpn_lshift (xp2, xp2, n + 1, 1));
+
+  neg = (mpn_cmp (xp2, tp, n + 1) < 0) ? ~0 : 0;
+
+#if HAVE_NATIVE_mpn_add_n_sub_n
+  if (neg)
+    mpn_add_n_sub_n (xp2, xm2, tp, xp2, n + 1);
+  else
+    mpn_add_n_sub_n (xp2, xm2, xp2, tp, n + 1);
+#else /* !HAVE_NATIVE_mpn_add_n_sub_n */
+  if (neg)
+    mpn_sub_n (xm2, tp, xp2, n + 1);
+  else
+    mpn_sub_n (xm2, xp2, tp, n + 1);
+
+  mpn_add_n (xp2, xp2, tp, n + 1);
+#endif /* !HAVE_NATIVE_mpn_add_n_sub_n */
+
+  ASSERT (xp2[n] < (1<<(k+2))-1);
+  ASSERT (xm2[n] < ((1<<(k+3))-1 - (1^k&1))/3);
+
+  neg ^= ((k & 1) - 1);
+
+  return neg;
+}
+
+#undef DO_addlsh2
-- 
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