===== RET cc and WAIT_n timing analysis =====
Normaly, without WAIT_n generator (even modulo 4), NOP should take 1 M-cycles and 4 T-states, so this instruction should pass using plustest.dsk at 0x00. Does fail here. In r005.6, cpctest.dsk did pass. Have to do somes experiments from it.
=== Test of a real Zilog 80 ===