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.

---
 .../mpn/generic/matrix22_mul1_inverse_vector.c     | 64 ++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 gmp-6.3.0/mpn/generic/matrix22_mul1_inverse_vector.c

(limited to 'gmp-6.3.0/mpn/generic/matrix22_mul1_inverse_vector.c')

diff --git a/gmp-6.3.0/mpn/generic/matrix22_mul1_inverse_vector.c b/gmp-6.3.0/mpn/generic/matrix22_mul1_inverse_vector.c
new file mode 100644
index 0000000..68d50b7
--- /dev/null
+++ b/gmp-6.3.0/mpn/generic/matrix22_mul1_inverse_vector.c
@@ -0,0 +1,64 @@
+/* matrix22_mul1_inverse_vector.c
+
+   THE FUNCTIONS IN THIS FILE ARE INTERNAL WITH MUTABLE INTERFACES.  IT IS ONLY
+   SAFE TO REACH THEM THROUGH DOCUMENTED INTERFACES.  IN FACT, IT IS ALMOST
+   GUARANTEED THAT THEY'LL CHANGE OR DISAPPEAR IN A FUTURE GNU MP RELEASE.
+
+Copyright 2008, 2010 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"
+#include "longlong.h"
+
+/* Sets (r;b) = M^{-1}(a;b), with M^{-1} = (u11, -u01; -u10, u00) from
+   the left. Uses three buffers, to avoid a copy. */
+mp_size_t
+mpn_matrix22_mul1_inverse_vector (const struct hgcd_matrix1 *M,
+				  mp_ptr rp, mp_srcptr ap, mp_ptr bp, mp_size_t n)
+{
+  mp_limb_t h0, h1;
+
+  /* Compute (r;b) <-- (u11 a - u01 b; -u10 a + u00 b) as
+
+     r  = u11 * a
+     r -= u01 * b
+     b *= u00
+     b -= u10 * a
+  */
+
+  h0 =    mpn_mul_1 (rp, ap, n, M->u[1][1]);
+  h1 = mpn_submul_1 (rp, bp, n, M->u[0][1]);
+  ASSERT (h0 == h1);
+
+  h0 =    mpn_mul_1 (bp, bp, n, M->u[0][0]);
+  h1 = mpn_submul_1 (bp, ap, n, M->u[1][0]);
+  ASSERT (h0 == h1);
+
+  n -= (rp[n-1] | bp[n-1]) == 0;
+  return n;
+}
-- 
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