WonderWitch bugs & oddities

This page is here to list all the know bugs and oddities of mainly the WonderWitch FreyaBIOS, and potentially the FreyaOS during my exploration of the code of this cart.


  • The callback and IRQ handler for vblankTimer can’t work as it is currently. It seems that a JMP is missing and it will work as the hblankTimer as it does not jump over the for for this int. This have two implications:
    • First the bit for the vblanktimer IRQ is not correctly cleared
    • There are some leftover on the stack and it can create problem on the long term.


  • The CPU IRQ for the Zero division, instead of being correctly set to the dummy handler at FD90:0009 is set to 0000:0009. Not a big issue per se, but still odd

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