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/sec_div.c | 131 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 131 insertions(+)
 create mode 100644 gmp-6.3.0/mpn/generic/sec_div.c

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

diff --git a/gmp-6.3.0/mpn/generic/sec_div.c b/gmp-6.3.0/mpn/generic/sec_div.c
new file mode 100644
index 0000000..1f08649
--- /dev/null
+++ b/gmp-6.3.0/mpn/generic/sec_div.c
@@ -0,0 +1,131 @@
+/* mpn_sec_div_qr, mpn_sec_div_r -- Compute Q = floor(U / V), U = U mod V.
+   Side-channel silent under the assumption that the used instructions are
+   side-channel silent.
+
+   Contributed to the GNU project by Torbjörn Granlund.
+
+Copyright 2011-2015 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"
+
+#if OPERATION_sec_div_qr
+#define FNAME mpn_sec_div_qr
+#define FNAME_itch mpn_sec_div_qr_itch
+#define Q(q) q,
+#define RETTYPE mp_limb_t
+#endif
+#if OPERATION_sec_div_r
+#define FNAME mpn_sec_div_r
+#define FNAME_itch mpn_sec_div_r_itch
+#define Q(q)
+#define RETTYPE void
+#endif
+
+mp_size_t
+FNAME_itch (mp_size_t nn, mp_size_t dn)
+{
+#if OPERATION_sec_div_qr
+/* Needs (nn + dn + 1) + mpn_sec_pi1_div_qr's needs of (2nn' - dn + 1) for a
+   total of 3nn + 4 limbs at tp.  Note that mpn_sec_pi1_div_qr's nn is one
+   greater than ours, therefore +4 and not just +2.  */
+  return 3 * nn + 4;
+#endif
+#if OPERATION_sec_div_r
+/* Needs (nn + dn + 1) + mpn_sec_pi1_div_r's needs of (dn + 1) for a total of
+   nn + 2dn + 2 limbs at tp.  */
+  return nn + 2 * dn + 2;
+#endif
+}
+
+RETTYPE
+FNAME (Q(mp_ptr qp)
+       mp_ptr np, mp_size_t nn,
+       mp_srcptr dp, mp_size_t dn,
+       mp_ptr tp)
+{
+  mp_limb_t d1, d0;
+  unsigned int cnt;
+  mp_limb_t inv32;
+
+  ASSERT (dn >= 1);
+  ASSERT (nn >= dn);
+  ASSERT (dp[dn - 1] != 0);
+
+  d1 = dp[dn - 1];
+  count_leading_zeros (cnt, d1);
+
+  if (cnt != 0)
+    {
+      mp_limb_t qh, cy;
+      mp_ptr np2, dp2;
+      dp2 = tp;					/* dn limbs */
+      mpn_lshift (dp2, dp, dn, cnt);
+
+      np2 = tp + dn;				/* (nn + 1) limbs */
+      cy = mpn_lshift (np2, np, nn, cnt);
+      np2[nn++] = cy;
+
+      d0 = dp2[dn - 1];
+      d0 += (~d0 != 0);
+      invert_limb (inv32, d0);
+
+      /* We add nn + dn to tp here, not nn + 1 + dn, as expected.  This is
+	 since nn here will have been incremented.  */
+#if OPERATION_sec_div_qr
+      qh = mpn_sec_pi1_div_qr (np2 + dn, np2, nn, dp2, dn, inv32, tp + nn + dn);
+      ASSERT (qh == 0);		/* FIXME: this indicates inefficiency! */
+      MPN_COPY (qp, np2 + dn, nn - dn - 1);
+      qh = np2[nn - 1];
+#else
+      mpn_sec_pi1_div_r (np2, nn, dp2, dn, inv32, tp + nn + dn);
+#endif
+
+      mpn_rshift (np, np2, dn, cnt);
+
+#if OPERATION_sec_div_qr
+      return qh;
+#endif
+    }
+  else
+    {
+      /* FIXME: Consider copying np => np2 here, adding a 0-limb at the top.
+	 That would simplify the underlying pi1 function, since then it could
+	 assume nn > dn.  */
+      d0 = dp[dn - 1];
+      d0 += (~d0 != 0);
+      invert_limb (inv32, d0);
+
+#if OPERATION_sec_div_qr
+      return mpn_sec_pi1_div_qr (qp, np, nn, dp, dn, inv32, tp);
+#else
+      mpn_sec_pi1_div_r (np, nn, dp, dn, inv32, tp);
+#endif
+    }
+}
-- 
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