invert_3 inverts all bits of x. Equivalent to x=~x.

lshift_3 shifts l to the left by r bits. Equivalent to l<<=r.

rshift_3 shifts l to the right by r bits. This shift is
arithmetic, so the sign of l is kept as is. Equivalent to l>>=r.

RETURN VALUE

invert_3 returns a pointer to x which has been updated in place.

Both lshift_3 and rshift_3 return a pointer to l which has
been updated in place.

EXAMPLES

Some bitwise operations on triple-ints:

unsigned x[3];
assign_int_3(x, -4);
invert_3(x); /* x is now 3 */
lshift_3(x, 42); /* x is now 3*2^42, if that fits in a triple-int */
rshift_3(x, 17); /* x is now 3*2^25 */