Register-less Interruptus

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Register-less Interruptus

Post by Twilighte »

Purely as an exploration(atm) i wondered what range of operations could be performed on the system through an interrupt without using x,y or a register.
For example i know we can check the interrupt that occurs using BIT followed by a branch (neither affecting registers).
We can also reset the IRQ with CMP or BIT.

One example is generating a triangle wave on Port A..

Code: Select all

      BIT DirFlag
      INC PortA
      JMP skip1
      DEC PortA
skip1 ASL DirFlag
      BCC skip2
      ROL DirFlag
Or something like this?

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