Rewrite/Nailify.

1 files changed, 58 insertions, 9 deletions

diff --git a/mpz/cdiv_ui.c b/mpz/cdiv_ui.c
index 41b149501..f86d082eb 100644
--- a/mpz/cdiv_ui.c
+++ b/mpz/cdiv_ui.c
@@ -28,17 +28,66 @@ MA 02111-1307, USA. */
 unsigned long int
 mpz_cdiv_ui (mpz_srcptr dividend, unsigned long int divisor)
 {
-  mp_size_t dividend_size;
-  mp_size_t size;
-  mp_limb_t remainder_limb;
+  mp_size_t ns, nn;
+  mp_ptr np;
+  mp_limb_t rl;
 
-  dividend_size = dividend->_mp_size;
-  size = ABS (dividend_size);
+  if (divisor == 0)
+    DIVIDE_BY_ZERO;
 
-  remainder_limb = mpn_mod_1 (dividend->_mp_d, size, (mp_limb_t) divisor);
+  ns = SIZ(dividend);
+  if (ns == 0)
+    {
+      return 0;
+    }
 
-  if (remainder_limb != 0 && dividend_size >= 0)
-    remainder_limb = divisor - remainder_limb;
+  nn = ABS(ns);
+  np = PTR(dividend);
+#if GMP_NAIL_BITS != 0
+  if (divisor > GMP_NUMB_MAX)
+    {
+      mp_limb_t dp[2], rp[2];
+      mp_ptr qp;
+      mp_size_t rn;
+      TMP_DECL (mark);
 
-  return remainder_limb;
+      if (nn == 1)		/* tdiv_qr requirements; tested above for 0 */
+	{
+	  rl = np[0];
+	  rp[0] = rl;
+	}
+      else
+	{
+	  TMP_MARK (mark);
+	  dp[0] = divisor & GMP_NUMB_MASK;
+	  dp[1] = divisor >> GMP_NUMB_BITS;
+	  qp = TMP_ALLOC_LIMBS (nn - 2 + 1);
+	  mpn_tdiv_qr (qp, rp, (mp_size_t) 0, np, nn, dp, (mp_size_t) 2);
+	  TMP_FREE (mark);
+	  rl = rp[0] + (rp[1] << GMP_NUMB_BITS);
+	}
+
+      if (rl != 0 && ns >= 0)
+	{
+	  rl = divisor - rl;
+	  rp[0] = rl & GMP_NUMB_MASK;
+	  rp[1] = rl >> GMP_NUMB_BITS;
+	}
+
+      rn = 1 + (rl > GMP_NUMB_MAX);  rn -= (rp[rn - 1] == 0);
+    }
+  else
+#endif
+    {
+      rl = mpn_mod_1 (np, nn, (mp_limb_t) divisor);
+      if (rl == 0)
+	;
+      else
+	{
+	  if (ns >= 0)
+	    rl = divisor - rl;
+	}
+    }
+
+  return rl;
 }