IRQ/Timer puzzles

I've got two puzzles a puzzle concerning slavio irq/timer behavior:

• qemu doesn't seem to behave as specified in the slavio documentation, I get an irq when I expect none.(no, it's ok, my test was just wrong)
• a real SS-20 doesn't seem to behave as specified in the slavio documentation, I don't get an irq, when I expect one.

I already found some places where the documentation is not precise, for instance it claims that reserved bits "read as 0, write has no effect", but they don't always read as 0, (may be they aren't really reserved?).

I miss my oscilloscope and direct access to the hw. If someone has a sun4m machine and an oscilloscope, please get in touch!