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Fix delay(). The processor cycle counter is a 32-bit wrapping counter.

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Hence, mask off the upper 32 bits and deal with wrap-arounds.

MFC after: 1 week
This commit is contained in:
marcel 2005-06-04 21:50:44 +00:00
parent aa557734c2
commit ed7fa679fa
1 changed files with 8 additions and 5 deletions
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13
sys/boot/alpha/libalpha/delay.c
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@ -33,9 +33,12 @@ __FBSDID("$FreeBSD$");
void
delay(int usecs)
{
struct rpb *hwrpb = (struct rpb *)HWRPB_ADDR;
unsigned long start = alpha_rpcc();
unsigned long end = start + (hwrpb->rpb_cc_freq * usecs) / 1000000;
while (alpha_rpcc() < end)
;
struct rpb *hwrpb = (struct rpb *)HWRPB_ADDR;
unsigned long end, now, start;
start = alpha_rpcc() & 0xfffffffful;
end = start + (hwrpb->rpb_cc_freq * usecs) / 1000000;
do {
now = alpha_rpcc() & 0xfffffffful;
} while (now < end || (now > start && end < start));
}