VIC, VideoRAM & charset location


  • MIRKOSOFT
  • 273 Aufrufe 0 Antworten

Diese Seite verwendet Cookies. Durch die Nutzung unserer Seite erklären Sie sich damit einverstanden, dass wir Cookies setzen. Weitere Informationen

  • VIC, VideoRAM & charset location

    Hi!
    I need to help with locating VideoRAM and Charset.
    In C64 could be located VideoRAM and Charset with registers VIC#24, CIA2#0 and address #648($288)
    VIC register #24 has two nibbles:
    bits 0-3 = relocating Charset data by step 2kB
    bits 4-7 = relocating VideoRAM
    e.g. default value was #21 (it's also using the same in C128), it's VideoRAM at 1024-2023 and charset in bank #5
    changing value to #24 relocates charset to bank #8 (8192-10239) and don't move VideoRAM (1024-2023)
    - this is working correctly also in C128 (#2604 is shadow register of #53272)
    But:
    I don't know how to relocate VIC-bank (if it is possible) - C64 it does with CIA2#0 (#56576) register by banks of size 16kB through bits 1 and 0.
    When I look at C128 memory map there's not the same using of #56576...
    and address #648:
    paging VideoRAM by step 256 Bytes. example 1024/256=4, so it's page #4, the value is #4...
    So, how to relocating VideoRAM and Charset in C128?
    All answers will be helpful.
    Thanks.
    Miro