@name bitwise
@inputs 
@outputs 
@persist 
@trigger 

function number real_index(Index) {
    return Index + bAnd(Index, bNot(7))
}

function number valid_index(Index) {
    return !bAnd(real_index(Index), 0x88)
}

for ( I = 1, 64 ) { print( I, valid_index(I - 1) ) }
