Nailify.

1 files changed, 71 insertions, 23 deletions

diff --git a/mpz/fdiv_qr_ui.c b/mpz/fdiv_qr_ui.c
index 7d26ec6de..2ff0f27e1 100644
--- a/mpz/fdiv_qr_ui.c
+++ b/mpz/fdiv_qr_ui.c
@@ -26,36 +26,84 @@ MA 02111-1307, USA. */
 unsigned long int
 mpz_fdiv_qr_ui (mpz_ptr quot, mpz_ptr rem, mpz_srcptr dividend, unsigned long int divisor)
 {
-  mp_size_t dividend_size;
-  mp_size_t size;
-  mp_ptr quot_ptr;
-  mp_limb_t remainder_limb;
+  mp_size_t ns, nn, qn;
+  mp_ptr np, qp;
+  mp_limb_t rl;
 
   if (divisor == 0)
     DIVIDE_BY_ZERO;
 
-  dividend_size = dividend->_mp_size;
-  size = ABS (dividend_size);
-
-  if (quot->_mp_alloc < size)
-    _mpz_realloc (quot, size);
-
-  quot_ptr = quot->_mp_d;
-
-  remainder_limb = mpn_divmod_1 (quot_ptr, dividend->_mp_d, size,
-				 (mp_limb_t) divisor);
-
-  if (remainder_limb != 0 && dividend_size < 0)
+  ns = SIZ(dividend);
+  if (ns == 0)
     {
-      mpn_incr_u (quot_ptr, (mp_limb_t) 1);
-      remainder_limb = divisor - remainder_limb;
+      SIZ(quot) = 0;
+      SIZ(rem) = 0;
+      return 0;
     }
 
-  size -= size != 0 && quot_ptr[size - 1] == 0;
-  quot->_mp_size = dividend_size >= 0 ? size : -size;
+  nn = ABS(ns);
+  MPZ_REALLOC (quot, nn);
+  qp = PTR(quot);
+  np = PTR(dividend);
 
-  rem->_mp_d[0] = remainder_limb;
-  rem->_mp_size = remainder_limb != 0;
+#if GMP_NAIL_BITS != 0
+  if (divisor > GMP_NUMB_MAX)
+    {
+      mp_limb_t dp[2];
+      mp_ptr rp;
+      mp_size_t rn;
+
+      MPZ_REALLOC (rem, 2);
+      rp = PTR(rem);
+
+      if (nn == 1)		/* tdiv_qr requirements; tested above for 0 */
+	{
+	  qp[0] = 0;
+	  qn = 1;		/* a white lie, fixed below */
+	  rl = np[0];
+	  rp[0] = rl;
+	}
+      else
+	{
+	  dp[0] = divisor & GMP_NUMB_MASK;
+	  dp[1] = divisor >> GMP_NUMB_BITS;
+	  mpn_tdiv_qr (qp, rp, (mp_size_t) 0, np, nn, dp, (mp_size_t) 2);
+	  rl = rp[0] + (rp[1] << GMP_NUMB_BITS);
+	  qn = nn - 2 + 1; 
+	}
+
+      if (rl != 0 && ns < 0)
+	{
+	  mpn_incr_u (qp, (mp_limb_t) 1);
+	  rl = divisor - rl;
+	  rp[0] = rl & GMP_NUMB_MASK;
+	  rp[1] = rl >> GMP_NUMB_BITS;
+	}
+
+      qn -= qp[qn - 1] == 0; qn -= qn != 0 && qp[qn - 1] == 0;
+      rn = 1 + (rl > GMP_NUMB_MAX);  rn -= (rp[rn - 1] == 0);
+      SIZ(rem) = rn;
+    }
+  else
+#endif
+    {
+      rl = mpn_divrem_1 (qp, (mp_size_t) 0, np, nn, (mp_limb_t) divisor);
+      if (rl == 0)
+	SIZ(rem) = 0;
+      else
+	{
+	  if (ns < 0)
+	    {
+	      mpn_incr_u (qp, (mp_limb_t) 1);
+	      rl = divisor - rl;
+	    }
+
+	  PTR(rem)[0] = rl;
+	  SIZ(rem) = rl != 0;
+	}
+      qn = nn - (qp[nn - 1] == 0);
+    }
 
-  return remainder_limb;
+  SIZ(quot) = ns >= 0 ? qn : -qn;
+  return rl;
 }