* mpz/mul.c: Use mpn_mul_1 for size==1 and mpn_mul_2 (if available)

	for size==2, to avoid copying; do vsize==0 test earlier.

1 files changed, 45 insertions, 15 deletions

diff --git a/mpz/mul.c b/mpz/mul.c
index 1925a87e9..58fc90fb4 100644
--- a/mpz/mul.c
+++ b/mpz/mul.c
@@ -26,6 +26,7 @@ MA 02111-1307, USA. */
 #include "mp.h"
 #endif
 
+
 void
 #ifndef BERKELEY_MP
 mpz_mul (mpz_ptr w, mpz_srcptr u, mpz_srcptr v)
@@ -39,23 +40,59 @@ mult (mpz_srcptr u, mpz_srcptr v, mpz_ptr w)
   mp_size_t sign_product;
   mp_ptr up, vp;
   mp_ptr wp;
-  mp_ptr free_me = NULL;
+  mp_ptr free_me;
   size_t free_me_size;
   mp_limb_t cy_limb;
   TMP_DECL (marker);
 
-  TMP_MARK (marker);
   sign_product = usize ^ vsize;
   usize = ABS (usize);
   vsize = ABS (vsize);
 
   if (usize < vsize)
     {
-      /* Swap U and V.  */
-      {const __mpz_struct *t = u; u = v; v = t;}
-      {mp_size_t t = usize; usize = vsize; vsize = t;}
+      MPZ_SRCPTR_SWAP (u, v);
+      MP_SIZE_T_SWAP (usize, vsize);
+    }
+
+  if (vsize == 0)
+    {
+      SIZ(w) = 0;
+      return;
     }
 
+#if HAVE_NATIVE_mpn_mul_2
+  if (vsize <= 2)
+    {
+      MPZ_REALLOC (w, usize+vsize);
+      wp = PTR(w);
+      if (vsize == 1)
+        cy_limb = mpn_mul_1 (wp, PTR(u), usize, PTR(v)[0]);
+      else
+        {
+          cy_limb = mpn_mul_2 (wp, PTR(u), usize, PTR(v)[0], PTR(v)[1]);
+          usize++;
+        }
+      wp[usize] = cy_limb;
+      usize += (cy_limb != 0);
+      SIZ(w) = (sign_product >= 0 ? usize : -usize);
+      return;
+    }      
+#else
+  if (vsize == 1)
+    {
+      MPZ_REALLOC (w, usize+1);
+      wp = PTR(w);
+      cy_limb = mpn_mul_1 (wp, PTR(u), usize, PTR(v)[0]);
+      wp[usize] = cy_limb;
+      usize += (cy_limb != 0);
+      SIZ(w) = (sign_product >= 0 ? usize : -usize);
+      return;
+    }      
+#endif
+
+  TMP_MARK (marker);
+  free_me = NULL;
   up = u->_mp_d;
   vp = v->_mp_d;
   wp = w->_mp_d;
@@ -98,16 +135,9 @@ mult (mpz_srcptr u, mpz_srcptr v, mpz_ptr w)
 	}
     }
 
-  if (vsize == 0)
-    {
-      wsize = 0;
-    }
-  else
-    {
-      cy_limb = mpn_mul (wp, up, usize, vp, vsize);
-      wsize = usize + vsize;
-      wsize -= cy_limb == 0;
-    }
+  cy_limb = mpn_mul (wp, up, usize, vp, vsize);
+  wsize = usize + vsize;
+  wsize -= cy_limb == 0;
 
   w->_mp_size = sign_product < 0 ? -wsize : wsize;
   if (free_me != NULL)