Avoid copying result when not needed. Misc cleanups.

1 files changed, 13 insertions, 11 deletions

diff --git a/mpf/get_str.c b/mpf/get_str.c
index e98397050..ca282ceb5 100644
--- a/mpf/get_str.c
+++ b/mpf/get_str.c
@@ -1,10 +1,10 @@
 /* mpf_get_str (digit_ptr, exp, base, n_digits, a) -- Convert the floating
-  point number A to a base BASE number and store N_DIGITS raw digits at
-  DIGIT_PTR, and the base BASE exponent in the word pointed to by EXP.  For
-  example, the number 3.1416 would be returned as "31416" in DIGIT_PTR and
-  1 in EXP.
+   point number A to a base BASE number and store N_DIGITS raw digits at
+   DIGIT_PTR, and the base BASE exponent in the word pointed to by EXP.  For
+   example, the number 3.1416 would be returned as "31416" in DIGIT_PTR and
+   1 in EXP.
 
-Copyright 1993, 1994, 1995, 1996, 1997, 2000, 2001, 2002, 2003, 2005 Free
+Copyright 1993, 1994, 1995, 1996, 1997, 2000, 2001, 2002, 2003, 2005, 2006 Free
 Software Foundation, Inc.
 
 This file is part of the GNU MP Library.
@@ -24,18 +24,16 @@ along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 MA 02110-1301, USA. */
 
-#include <stdlib.h>		/* for NULL */
+#include <stdio.h>		/* for NULL */
 #include "gmp.h"
 #include "gmp-impl.h"
 #include "longlong.h"		/* for count_leading_zeros */
 
 /* Could use some more work.
 
-   1. Don't unconditionally allocate temps on the stack.
-   2. Make one temp alloc block, and split it manually.
-   3. Allocation is excessive.  Try to combine areas.  Perhaps use result
+   1. Allocation is excessive.  Try to combine areas.  Perhaps use result
       string area for temp limb space?
-   4. We generate up to two limbs worth of digits.  This is because we don't
+   2. We generate up to two limbs of extra digits.  This is because we don't
       check the exact number of bits in the input operand, and from that
       compute an accurate exponent (variable e in the code).  It would be
       cleaner and probably somewhat faster to change this.
@@ -97,12 +95,16 @@ mpn_pow_1_highpart (mp_ptr rp, mp_size_t *ignp,
 
   if (rn > prec)
     {
+      ASSERT (rn == prec + 1);
+
       ign += rn - prec;
       rp += rn - prec;
       rn = prec;
     }
 
-  MPN_COPY_INCR (passed_rp, rp + off, rn);
+  /* With somewhat less than 50% probability, we can skip this copy.  */
+  if (passed_rp != rp + off)
+    MPN_COPY_INCR (passed_rp, rp + off, rn);
   *ignp = ign;
   return rn;
 }