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/divrem_2.c | 118 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 118 insertions(+)
 create mode 100644 gmp-6.3.0/mpn/generic/divrem_2.c

(limited to 'gmp-6.3.0/mpn/generic/divrem_2.c')

diff --git a/gmp-6.3.0/mpn/generic/divrem_2.c b/gmp-6.3.0/mpn/generic/divrem_2.c
new file mode 100644
index 0000000..217f2f6
--- /dev/null
+++ b/gmp-6.3.0/mpn/generic/divrem_2.c
@@ -0,0 +1,118 @@
+/* mpn_divrem_2 -- Divide natural numbers, producing both remainder and
+   quotient.  The divisor is two limbs.
+
+   THIS FILE CONTAINS INTERNAL FUNCTIONS 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 1993-1996, 1999-2002 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"
+
+
+/* Divide num {np,nn} by den {dp,2} and write the nn-2 least significant
+   quotient limbs at qp and the 2 long remainder at np.  If qxn is non-zero,
+   generate that many fraction bits and append them after the other quotient
+   limbs.  Return the most significant limb of the quotient, this is always 0
+   or 1.
+
+   Preconditions:
+   1. The most significant bit of the divisor must be set.
+   2. qp must either not overlap with the input operands at all, or
+      qp >= np + 2 must hold true.  (This means that it's possible to put
+      the quotient in the high part of {np,nn}, right above the remainder.
+   3. nn >= 2, even if qxn is non-zero.  */
+
+mp_limb_t
+mpn_divrem_2 (mp_ptr qp, mp_size_t qxn,
+	      mp_ptr np, mp_size_t nn,
+	      mp_srcptr dp)
+{
+  mp_limb_t most_significant_q_limb;
+  mp_size_t i;
+  mp_limb_t r1, r0, d1, d0;
+  gmp_pi1_t di;
+
+  ASSERT (nn >= 2);
+  ASSERT (qxn >= 0);
+  ASSERT (dp[1] & GMP_NUMB_HIGHBIT);
+  ASSERT (! MPN_OVERLAP_P (qp, nn-2+qxn, np, nn) || qp >= np+2);
+  ASSERT_MPN (np, nn);
+  ASSERT_MPN (dp, 2);
+
+  np += nn - 2;
+  d1 = dp[1];
+  d0 = dp[0];
+  r1 = np[1];
+  r0 = np[0];
+
+  most_significant_q_limb = 0;
+  if (r1 >= d1 && (r1 > d1 || r0 >= d0))
+    {
+#if GMP_NAIL_BITS == 0
+      sub_ddmmss (r1, r0, r1, r0, d1, d0);
+#else
+      r0 = r0 - d0;
+      r1 = r1 - d1 - (r0 >> GMP_LIMB_BITS - 1);
+      r0 &= GMP_NUMB_MASK;
+#endif
+      most_significant_q_limb = 1;
+    }
+
+  invert_pi1 (di, d1, d0);
+
+  qp += qxn;
+
+  for (i = nn - 2 - 1; i >= 0; i--)
+    {
+      mp_limb_t n0, q;
+      n0 = np[-1];
+      udiv_qr_3by2 (q, r1, r0, r1, r0, n0, d1, d0, di.inv32);
+      np--;
+      qp[i] = q;
+    }
+
+  if (UNLIKELY (qxn != 0))
+    {
+      qp -= qxn;
+      for (i = qxn - 1; i >= 0; i--)
+	{
+	  mp_limb_t q;
+	  udiv_qr_3by2 (q, r1, r0, r1, r0, CNST_LIMB(0), d1, d0, di.inv32);
+	  qp[i] = q;
+	}
+    }
+
+  np[1] = r1;
+  np[0] = r0;
+
+  return most_significant_q_limb;
+}
-- 
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