Reorganisation of the source tree

[ghc-hetmet.git] / rts / gmp / mpn / generic / perfsqr.c

diff --git a/rts/gmp/mpn/generic/perfsqr.c b/rts/gmp/mpn/generic/perfsqr.c
new file mode 100644 (file)
index 0000000..42ee340
--- /dev/null
+++ b/rts/gmp/mpn/generic/perfsqr.c
@@ -0,0 +1,123 @@
+/* mpn_perfect_square_p(u,usize) -- Return non-zero if U is a perfect square,
+   zero otherwise.
+
+Copyright (C) 1991, 1993, 1994, 1996, 1997, 2000 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 the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or (at your
+option) any later version.
+
+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 Lesser General Public
+License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+MA 02111-1307, USA. */
+
+#include <stdio.h> /* for NULL */
+#include "gmp.h"
+#include "gmp-impl.h"
+#include "longlong.h"
+
+
+/* sq_res_0x100[x mod 0x100] == 1 iff x mod 0x100 is a quadratic residue
+   modulo 0x100.  */
+static unsigned char const sq_res_0x100[0x100] =
+{
+  1,1,0,0,1,0,0,0,0,1,0,0,0,0,0,0,1,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,
+  0,1,0,0,1,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,
+  1,1,0,0,1,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,
+  0,1,0,0,1,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,
+  0,1,0,0,1,0,0,0,0,1,0,0,0,0,0,0,1,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,
+  0,1,0,0,1,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,
+  0,1,0,0,1,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,
+  0,1,0,0,1,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1,0,0,0,0,0,0,
+};
+
+int
+#if __STDC__
+mpn_perfect_square_p (mp_srcptr up, mp_size_t usize)
+#else
+mpn_perfect_square_p (up, usize)
+     mp_srcptr up;
+     mp_size_t usize;
+#endif
+{
+  mp_limb_t rem;
+  mp_ptr root_ptr;
+  int res;
+  TMP_DECL (marker);
+
+  /* The first test excludes 55/64 (85.9%) of the perfect square candidates
+     in O(1) time.  */
+  if ((sq_res_0x100[(unsigned int) up[0] % 0x100] & 1) == 0)
+    return 0;
+
+#if defined (PP)
+  /* The second test excludes 30652543/30808063 (99.5%) of the remaining
+     perfect square candidates in O(n) time.  */
+
+  /* Firstly, compute REM = A mod PP.  */
+  if (UDIV_TIME > (2 * UMUL_TIME + 6))
+    rem = mpn_preinv_mod_1 (up, usize, (mp_limb_t) PP, (mp_limb_t) PP_INVERTED);
+  else
+    rem = mpn_mod_1 (up, usize, (mp_limb_t) PP);
+
+  /* Now decide if REM is a quadratic residue modulo the factors in PP.  */
+
+  /* If A is just a few limbs, computing the square root does not take long
+     time, so things might run faster if we limit this loop according to the
+     size of A.  */
+
+#if BITS_PER_MP_LIMB == 64
+  if (((CNST_LIMB(0x12DD703303AED3) >> rem % 53) & 1) == 0)
+    return 0;
+  if (((CNST_LIMB(0x4351B2753DF) >> rem % 47) & 1) == 0)
+    return 0;
+  if (((CNST_LIMB(0x35883A3EE53) >> rem % 43) & 1) == 0)
+    return 0;
+  if (((CNST_LIMB(0x1B382B50737) >> rem % 41) & 1) == 0)
+    return 0;
+  if (((CNST_LIMB(0x165E211E9B) >> rem % 37) & 1) == 0)
+    return 0;
+  if (((CNST_LIMB(0x121D47B7) >> rem % 31) & 1) == 0)
+    return 0;
+#endif
+  if (((0x13D122F3L >> rem % 29) & 1) == 0)
+    return 0;
+  if (((0x5335FL >> rem % 23) & 1) == 0)
+    return 0;
+  if (((0x30AF3L >> rem % 19) & 1) == 0)
+    return 0;
+  if (((0x1A317L >> rem % 17) & 1) == 0)
+    return 0;
+  if (((0x161BL >> rem % 13) & 1) == 0)
+    return 0;
+  if (((0x23BL >> rem % 11) & 1) == 0)
+    return 0;
+  if (((0x017L >> rem % 7) & 1) == 0)
+    return 0;
+  if (((0x13L >> rem % 5) & 1) == 0)
+    return 0;
+  if (((0x3L >> rem % 3) & 1) == 0)
+    return 0;
+#endif
+
+  TMP_MARK (marker);
+
+  /* For the third and last test, we finally compute the square root,
+     to make sure we've really got a perfect square.  */
+  root_ptr = (mp_ptr) TMP_ALLOC ((usize + 1) / 2 * BYTES_PER_MP_LIMB);
+
+  /* Iff mpn_sqrtrem returns zero, the square is perfect.  */
+  res = ! mpn_sqrtrem (root_ptr, NULL, up, usize);
+  TMP_FREE (marker);
+  return res;
+}