Author: hselasky
Date: Wed Dec 3 21:55:44 2014
New Revision: 275468
URL: https://svnweb.freebsd.org/changeset/base/275468
Log:
Optimise the bit searching loops, by quickly skipping the 16 first set
bits if all the 16 first bits are set. This way the worst case
searching time is reduced from 32 to 16 cycles.
Modified:
head/sys/dev/usb/controller/saf1761_otg.c
Modified: head/sys/dev/usb/controller/saf1761_otg.c
==============================================================================
--- head/sys/dev/usb/controller/saf1761_otg.c Wed Dec 3 21:48:30 2014
(r275467)
+++ head/sys/dev/usb/controller/saf1761_otg.c Wed Dec 3 21:55:44 2014
(r275468)
@@ -230,7 +230,7 @@ saf1761_host_channel_alloc(struct saf176
map = sc->sc_host_intr_map |
sc->sc_host_intr_busy_map[0] |
sc->sc_host_intr_busy_map[1];
- for (x = 0; x != 32; x++) {
+ for (x = ((map & 0xFFFF) == 0xFFFF) ? 16 : 0; x != 32; x++) {
if (map & (1 << x))
continue;
sc->sc_host_intr_map |= (1 << x);
@@ -242,7 +242,7 @@ saf1761_host_channel_alloc(struct saf176
map = sc->sc_host_isoc_map |
sc->sc_host_isoc_busy_map[0] |
sc->sc_host_isoc_busy_map[1];
- for (x = 0; x != 32; x++) {
+ for (x = ((map & 0xFFFF) == 0xFFFF) ? 16 : 0; x != 32; x++) {
if (map & (1 << x))
continue;
sc->sc_host_isoc_map |= (1 << x);
@@ -254,7 +254,7 @@ saf1761_host_channel_alloc(struct saf176
map = sc->sc_host_async_map |
sc->sc_host_async_busy_map[0] |
sc->sc_host_async_busy_map[1];
- for (x = 0; x != 32; x++) {
+ for (x = ((map & 0xFFFF) == 0xFFFF) ? 16 : 0; x != 32; x++) {
if (map & (1 << x))
continue;
sc->sc_host_async_map |= (1 << x);
_______________________________________________
svn-src-all@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-all
To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
