code: drawterm

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devmnt: use u32int for tagmask, simplify alloctag()

the ~0UL constant is 64 bit on amd64/gcc, which made the
if(v == ~0UL) always false causing every bit to be probed.

--- a/kern/devmnt.c

+++ b/kern/devmnt.c

@@ -32,7 +32,7 @@

 enum

 {

-	TAGSHIFT = 5,			/* ulong has to be 32 bits */

+	TAGSHIFT = 5,

 	TAGMASK = (1<<TAGSHIFT)-1,

 	NMASK = (64*1024)>>TAGSHIFT,

 };

@@ -46,7 +46,7 @@

 	ulong	nrpcfree;

 	ulong	nrpcused;

 	ulong	id;

-	ulong	tagmask[NMASK];

+	u32int	tagmask[NMASK];

 } mntalloc;

 static Chan*	mntchan(void);

@@ -74,7 +74,7 @@

 {

 	mntalloc.id = 1;

 	mntalloc.tagmask[0] = 1;			/* don't allow 0 as a tag */

-	mntalloc.tagmask[NMASK-1] = 0x80000000UL;	/* don't allow NOTAG */

+	mntalloc.tagmask[NMASK-1] = 0x80000000;		/* don't allow NOTAG */

 	fmtinstall('F', fcallfmt);

 	fmtinstall('D', dirfmt);

 /* We can't install %M since eipfmt does and is used in the kernel [sape] */

@@ -975,17 +975,16 @@

 alloctag(void)

 {

 	int i, j;

-	ulong v;

+	u32int v;

 	for(i = 0; i < NMASK; i++){

 		v = mntalloc.tagmask[i];

-		if(v == ~0UL)

+		if(v == -1)

 			continue;

-		for(j = 0; j < 1<<TAGSHIFT; j++)

-			if((v & (1<<j)) == 0){

-				mntalloc.tagmask[i] |= 1<<j;

-				return (i<<TAGSHIFT) + j;

-			}

+		for(j = 0; (v & 1) != 0; j++)

+			v >>= 1;

+		mntalloc.tagmask[i] |= 1<<j;

+		return i<<TAGSHIFT | j;

 	}

 	panic("no friggin tags left");

 	return NOTAG;