S1
#define S1(x) (CYCLIC (x, 6) ^ CYCLIC (x, 11) ^ CYCLIC (x, 25))
#define S1(x) (CYCLIC (x, 14) ^ CYCLIC (x, 18) ^ CYCLIC (x, 41))
S1=1, S2, S3, S4, S5, S6, S7, S8
#define S1 1 /* button 1 delayed down */