+#define __bitop(x,i,o) ((x)[(i)/8] o (1<<(i)%8))
+#define setbit(x,i) __bitop(x,i,|=)
+#define clrbit(x,i) __bitop(x,i,&=~)
+#define isset(x,i) __bitop(x,i,&)
+#define isclr(x,i) !isset(x,i)
+
+#define howmany(n,d) (((n)+((d)-1))/(d))
+#define roundup(n,d) (howmany(n,d)*(d))
+#define powerof2(n) !(((n)-1) & (n))