Add Chromium-only Blender WebEngine parity work

blender-5.2.0/extern/gmp-source/mpf/sqrt_ui.c

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+/* mpf_sqrt_ui -- Compute the square root of an unsigned integer.
+
+Copyright 1993, 1994, 1996, 2000, 2001, 2004, 2005, 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 <stdio.h> /* for NULL */
+#include "gmp-impl.h"
+
+
+/* As usual the aim is to produce PREC(r) limbs of result with the high limb
+   non-zero.  That high limb will end up floor(sqrt(u)), and limbs below are
+   produced by padding the input with zeros, two for each desired result
+   limb, being 2*(prec-1) for a total 2*prec-1 limbs passed to mpn_sqrtrem.
+   The way mpn_sqrtrem calculates floor(sqrt(x)) ensures the root is correct
+   to the intended accuracy, ie. truncated to prec limbs.
+
+   With nails, u might be two limbs, in which case a total 2*prec limbs is
+   passed to mpn_sqrtrem (still giving a prec limb result).  If uhigh is
+   zero we adjust back to 2*prec-1, since mpn_sqrtrem requires the high
+   non-zero.  2*prec limbs are always allocated, even when uhigh is zero, so
+   the store of uhigh can be done without a conditional.
+
+   u==0 is a special case so the rest of the code can assume the result is
+   non-zero (ie. will have a non-zero high limb on the result).
+
+   Not done:
+
+   No attempt is made to identify perfect squares.  It's considered this can
+   be left to an application if it might occur with any frequency.  As it
+   stands, mpn_sqrtrem does its normal amount of work on a perfect square
+   followed by zero limbs, though of course only an mpn_sqrtrem1 would be
+   actually needed.  We also end up leaving our mpf result with lots of low
+   trailing zeros, slowing down subsequent operations.
+
+   We're not aware of any optimizations that can be made using the fact the
+   input has lots of trailing zeros (apart from the perfect square
+   case).  */
+
+
+/* 1 if we (might) need two limbs for u */
+#define U2   (GMP_NUMB_BITS < BITS_PER_ULONG)
+
+void
+mpf_sqrt_ui (mpf_ptr r, unsigned long int u)
+{
+  mp_size_t rsize, zeros;
+  mp_ptr tp;
+  mp_size_t prec;
+  TMP_DECL;
+
+  if (UNLIKELY (u <= 1))
+    {
+      SIZ (r) = EXP (r) = u;
+      *PTR (r) = u;
+      return;
+    }
+
+  TMP_MARK;
+
+  prec = PREC (r);
+  zeros = 2 * prec - 2;
+  rsize = zeros + 1 + U2;
+
+  tp = TMP_ALLOC_LIMBS (rsize);
+
+  MPN_ZERO (tp, zeros);
+  tp[zeros] = u & GMP_NUMB_MASK;
+
+#if U2
+  {
+    mp_limb_t uhigh = u >> GMP_NUMB_BITS;
+    tp[zeros + 1] = uhigh;
+    rsize -= (uhigh == 0);
+  }
+#endif
+
+  mpn_sqrtrem (PTR (r), NULL, tp, rsize);
+
+  SIZ (r) = prec;
+  EXP (r) = 1;
+  TMP_FREE;
+}