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Optimise the bit searching loops, by quickly skipping the 16 first set

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bits if all the 16 first bits are set. This way the worst case
searching time is reduced from 32 to 16 cycles.
This commit is contained in:
Hans Petter Selasky 2014-12-03 21:55:44 +00:00
parent e93086d0bf
commit 157675bd2d
1 changed files with 3 additions and 3 deletions
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6
sys/dev/usb/controller/saf1761_otg.c
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@ -230,7 +230,7 @@ saf1761_host_channel_alloc(struct saf1761_otg_softc *sc, struct saf1761_otg_td *
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 saf1761_otg_softc *sc, struct saf1761_otg_td *
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 saf1761_otg_softc *sc, struct saf1761_otg_td *
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);