UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - How do I convert hex files to binary for use in the MK14 mame VDU emulator?

Timbucus · 7th Dec 2022, 9:42 pm

No that code is a bit tricky the XPAL 0 is a trick to move around on the current page by setting just the low byte of the Program counter. P3 has previously been set to the address of the SCIOS ROM routine at 0x22 which the XPPC3 correctly then executes saving the return address in P3 of course.

If the SCIOS rom image is not V2 then that will be wrong but 23 is the debug entry point on that so it sits there waiting for the GO key to run the game after the initialisation which 'returns' back to 0F21 as P3 is saved on entry to that rom routine

7th Dec 2022, 9:42 pm	#85
Timbucus Octode Join Date: Mar 2019 Location: Barry, Vale of Glamorgan, Wales, UK. Posts: 1,363	Re: How do I convert hex files to binary for use in the MK14 mame VDU emulator? No that code is a bit tricky the XPAL 0 is a trick to move around on the current page by setting just the low byte of the Program counter. P3 has previously been set to the address of the SCIOS ROM routine at 0x22 which the XPPC3 correctly then executes saving the return address in P3 of course. If the SCIOS rom image is not V2 then that will be wrong but 23 is the debug entry point on that so it sits there waiting for the GO key to run the game after the initialisation which 'returns' back to 0F21 as P3 is saved on entry to that rom routine