Obsah
2 External clock
XTAL (39) and EXTAL (38) slouží pro připojení krystalu, alternativně na EXTAL 38 mohou být připojeny externí TTL hodiny, XTAL se pak nechá nezapojený (plovoucí)
3 Missing instructions
- ABA ADD acumulator B to acumulator A
PSHS B ADDA ,S+
wer twtre
- wer
- something else
4 Optimalizace 6309
- AIM - AND with Immediate
7/4 AIM #~$40,V_ACIA_CTRL_byte 4/3 LDA V_ACIA_CTRL_byte 11/7 (nebo 7/4) vs. 4/3 LDA V_ACIA_CTRL_byte 2/2 ANDA #~$40 4/3 STA V_ACIA_CTRL_byte 10/8
7 Push order for 6809 stack:
(Made with DrawIt VIM plugin)
New S Old S | | | | $0000 v v $FFFF +--+- -+--+--+--+--+--+--+--+--+--+--+--+--+---+---+--+--+--+--+- -+--+ |..|.......|..|..|CC| A| B|DP|Xh|Xl|Yh|Yl|Uh|Ul|PCh|PCl|##|##|##|..|.......|..| +--+- -+--+--+--+--+--+--+--+--+--+--+--+--+---+---+--+--+--+--+- -+--+ |Sh|Sl| +--+--+ for PSHU ... PUSH / PULL order +-----+-----------------------------+ | CC | Condition Code Register | . | +-----+-----------------------------+ /_\ | | A | A Accumulator | | | +-----+-----------------------------+ | | B | B Accumulator | | P +-----+-----------------------------+ U | DP | Direct Page Register | P L +-----+-----------------------------+ U L | X | X Index Register | S +-----+-----------------------------+ H | | Y | Y Index Register | | +-----+-----------------------------+ | _|_ | S/U | Hardware/User Stack Pointer | | \ / +-----+-----------------------------+ | ' | PC | Program Counter | +-----+-----------------------------+