Post by mirkosoft on Apr 27, 2016 19:06:58 GMT
Difference is not in performing operation, but in memory access.
Example:
LD A, ($d020) = loads value of address $d020 accessing only RAM location, not IO
IN A, (C) = loads value of IO address in BC register pair, if it contains $d020, reads IO value - so correctly VIC2E border
LD ($d020), A = places value in A to RAM location $d020, no like IO area
OUT (C), A = places value in A to IO address in register pair BC, if contains $d020, correctly changes border...
Z80 addressing RAM access is bit different, and I forgot it in case Z80 to Z80 switch - locations for switch are IO locations. Access RAM carefully.
Miro
Example:
LD A, ($d020) = loads value of address $d020 accessing only RAM location, not IO
IN A, (C) = loads value of IO address in BC register pair, if it contains $d020, reads IO value - so correctly VIC2E border
LD ($d020), A = places value in A to RAM location $d020, no like IO area
OUT (C), A = places value in A to IO address in register pair BC, if contains $d020, correctly changes border...
Z80 addressing RAM access is bit different, and I forgot it in case Z80 to Z80 switch - locations for switch are IO locations. Access RAM carefully.
Miro