From 65fc2758670c06dcb89d1bd829f990290c74e8c3 Mon Sep 17 00:00:00 2001
From: dgp <dgp@users.sourceforge.net>
Date: Sat, 27 Aug 2011 02:28:47 +0000
Subject: Repaired the lost performance in the copy loop hotspots. Now meets
or beats the former trunk (and current trunk by magnitudes) in tclbench.
---
generic/tclStringObj.c | 25 ++++++++++++-------------
1 file changed, 12 insertions(+), 13 deletions(-)
diff --git a/generic/tclStringObj.c b/generic/tclStringObj.c
index 27480c5..bccd28a 100644
--- a/generic/tclStringObj.c
+++ b/generic/tclStringObj.c
@@ -2660,18 +2660,17 @@ ReverseBytes(
int count) /* Until this many are copied, */
/* reversing as you go. */
{
+ unsigned char *src = from + count - 1;
if (to == from) {
/* Reversing in place */
- from += count - 1;
- while (to < from) {
- unsigned char c = *from;
- *from-- = *to;
+ while (to < src) {
+ unsigned char c = *src;
+ *src-- = *to;
*to++ = c;
}
} else {
- from += count - 1;
- while (count--) {
- *to++ = *from--;
+ while (src >= from) {
+ *to++ = *src--;
}
}
}
@@ -2683,18 +2682,18 @@ ReverseUniChars(
unsigned int count) /* Until this many are copied, */
/* reversing as you go. */
{
+ Tcl_UniChar *src = from + count - 1;
if (to == from) {
/* Reversing in place */
from += count - 1;
- while (to < from) {
- Tcl_UniChar c = *from;
- *from-- = *to;
+ while (to < src) {
+ Tcl_UniChar c = *src;
+ *src-- = *to;
*to++ = c;
}
} else {
- from += count - 1;
- while (count--) {
- *to++ = *from--;
+ while (src >= from) {
+ *to++ = *src--;
}
}
}
--
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