Heaven/TQA Posted April 18, 2019 Share Posted April 18, 2019 (edited) Can someone explain me those output? I am on a standard 128kb 7 banks SGR cart... How can the CPU do such things? And what are undefined Maria reads? Edited April 18, 2019 by Heaven/TQA Quote Link to comment Share on other sites More sharing options...
Heaven/TQA Posted April 18, 2019 Author Share Posted April 18, 2019 how can A7800 read from memory with a LSR? don't get that... same with unmapped memory reads. Quote Link to comment Share on other sites More sharing options...
RevEng Posted April 18, 2019 Share Posted April 18, 2019 Undefined MARIA reads means you are reading from a write-only register. As far as register opcodes causing a read, this is inherited from MAME... I believe this comes into play if you trap on a value less than 256. The emulator traps on the opcode (or argument) getting loaded onto the bus for the 6502. I haven't found a convenient workaround yet. 1 Quote Link to comment Share on other sites More sharing options...
Heaven/TQA Posted April 18, 2019 Author Share Posted April 18, 2019 Ok.... can I trust mame/a7800 or ignore? Quote Link to comment Share on other sites More sharing options...
RevEng Posted April 18, 2019 Share Posted April 18, 2019 About the undefined reads? Yes. That comes from the Maria driver. 1 Quote Link to comment Share on other sites More sharing options...
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