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/redc_n.c | 80 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 gmp-6.3.0/mpn/generic/redc_n.c

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

diff --git a/gmp-6.3.0/mpn/generic/redc_n.c b/gmp-6.3.0/mpn/generic/redc_n.c
new file mode 100644
index 0000000..0c94b7c
--- /dev/null
+++ b/gmp-6.3.0/mpn/generic/redc_n.c
@@ -0,0 +1,80 @@
+/* mpn_redc_n.  Set rp[] <- up[]/R^n mod mp[].  Clobber up[].
+   mp[] is n limbs; up[] is 2n limbs, the inverse ip[] is n limbs.
+
+   THIS IS AN INTERNAL FUNCTION WITH A MUTABLE INTERFACE.  IT IS ONLY
+   SAFE TO REACH THIS FUNCTION THROUGH DOCUMENTED INTERFACES.
+
+Copyright 2009, 2012 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"
+
+/*
+  TODO
+
+  * We assume mpn_mulmod_bnm1 is always faster than plain mpn_mul_n (or a
+    future mpn_mulhi) for the range we will be called.  Follow up that
+    assumption.
+
+  * Decrease scratch usage.
+
+  * Consider removing the residue canonicalisation.
+*/
+
+void
+mpn_redc_n (mp_ptr rp, mp_ptr up, mp_srcptr mp, mp_size_t n, mp_srcptr ip)
+{
+  mp_ptr xp, yp, scratch;
+  mp_limb_t cy;
+  mp_size_t rn;
+  TMP_DECL;
+  TMP_MARK;
+
+  ASSERT (n > 8);
+
+  rn = mpn_mulmod_bnm1_next_size (n);
+
+  scratch = TMP_ALLOC_LIMBS (n + rn + mpn_mulmod_bnm1_itch (rn, n, n));
+
+  xp = scratch;
+  mpn_mullo_n (xp, up, ip, n);
+
+  yp = scratch + n;
+  mpn_mulmod_bnm1 (yp, rn, xp, n, mp, n, scratch + n + rn);
+
+  ASSERT_ALWAYS (2 * n > rn);				/* could handle this */
+
+  cy = mpn_sub_n (yp + rn, yp, up, 2*n - rn);		/* undo wrap around */
+  MPN_DECR_U (yp + 2*n - rn, rn, cy);
+
+  cy = mpn_sub_n (rp, up + n, yp + n, n);
+  if (cy != 0)
+    mpn_add_n (rp, rp, mp, n);
+
+  TMP_FREE;
+}
-- 
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