STZ STZ Store zero in memory STZ N V M X D I Z C Operation: 0 -> M . . . . . . . . 4510 Versions: +----------------+-----------------------+---------+---------+----------+ | Addressing Mode| Assembly Language Form| OP CODE |No. Bytes|No. Cycles| +----------------+-----------------------+---------+---------+----------+ | Direct Page | STZ $FF | $64 | 2 | 3 | | Direct Page,X | STZ $FF,X | $74 | 2 | 3 | | Absolute | STZ $FFFF | $9C | 3 | ? | | Absolute,X | STZ $FFFF,X | $9E | 3 | ? | +----------------+-----------------------+---------+---------+----------+ 65816 Versions: +----------------+-----------------------+---------+---------+----------+ | Addressing Mode| Assembly Language Form| OP CODE |No. Bytes|No. Cycles| +----------------+-----------------------+---------+---------+----------+ | Absolute | STZ $FFFF | $9C | 3 | 4 | | Absolute,X | STZ $FFFF,X | $9E | 3 | 5 | | Direct Page | STZ $FF | $64 | 2 | 3 | | Direct Page,X | STZ $FF,X | $74 | 2 | 4 | +----------------+-----------------------+---------+---------+----------+ For penalty cycles on the 65816, check the desired addressing mode.