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Christos was worried about clrbits() being called with a length of zero.

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This can't happen, but rework so it doesn't matter.
Remove 'optimisation' for length 1, that doesn't happen often enough.
This commit is contained in:
dsl 2009-11-14 13:18:41 +00:00
parent f2999773ff
commit e6a11930a4
1 changed files with 17 additions and 21 deletions
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38
sys/kern/tty_subr.c
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@ -1,4 +1,4 @@
/* $NetBSD: tty_subr.c,v 1.38 2009/11/13 19:15:24 dsl Exp $ */
/* $NetBSD: tty_subr.c,v 1.39 2009/11/14 13:18:41 dsl Exp $ */
/*
* Copyright (c) 1993, 1994 Theo de Raadt
@ -29,7 +29,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: tty_subr.c,v 1.38 2009/11/13 19:15:24 dsl Exp $");
__KERNEL_RCSID(0, "$NetBSD: tty_subr.c,v 1.39 2009/11/14 13:18:41 dsl Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@ -303,32 +303,28 @@ out:
static void
clrbits(u_char *cp, unsigned int off, unsigned int len)
{
unsigned int sby, sbi, eby, ebi;
unsigned int i;
u_char mask;
unsigned int sbi, ebi;
u_char *scp, *ecp;
unsigned int end;
unsigned char mask;
if (len==1) {
clrbit(cp, off);
return;
}
len--;
sby = off / NBBY;
scp = cp + off / NBBY;
sbi = off % NBBY;
eby = (off+len) / NBBY;
ebi = (off+len) % NBBY + 1;
if (sby == eby) {
mask = ((1 << (ebi - sbi)) - 1) << sbi;
cp[sby] &= ~mask;
end = off + len + NBBY - 1;
ecp = cp + end / NBBY - 1;
ebi = end % NBBY + 1;
if (scp >= ecp) {
mask = ((1 << len) - 1) << sbi;
*scp &= ~mask;
} else {
mask = (1 << sbi) - 1;
cp[sby++] &= mask;
*scp++ &= mask;
mask = (1 << ebi) - 1;
cp[eby] &= ~mask;
*ecp &= ~mask;
for (i = sby; i < eby; i++)
cp[i] = 0x00;
while (scp < ecp)
*scp++ = 0x00;
}
}
#endif