ggidev-invert_3, ggidev-lshift_3, ggidev-rshift_3 - Bitwise triple-int
unsigned *invert_3(unsigned x);
unsigned *lshift_3(unsigned l, unsigned r);
unsigned *rshift_3(unsigned l, unsigned r);
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.
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
Some bitwise operations on triple-ints:
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 */