Space Invaders Question

I want to test out the sounds and switch settings on this game by
reading and writing data to certain I/O ports using my Fluke 9010a
troubleshooter. I looked on spies to get the memory map information,
but I guess I need help interpretting this. How do I figure out what
addresses to read or write to based on this information?
http://surfin.spies.com/arcade/simulation/gameHardware/SpaceInvaders.txt
- or does someone have the addresses more clearly mapped out that I can
use?

I/O map
-------

*** Port 1
[IN]Controller

bit 0=CREDIT (0 if deposit)
bit 1=2P start(1 if pressed)
bit 2=1P start(1 if pressed)
bit 3=0 if TILT
bit 4=shot(1 if pressed)
bit 5=left(1 if pressed)
bit 6=right(1 if pressed)
bit 7=Always 1

*** Port 2
[IN]Controller
bit 0=Always 0
bit 1=Always 0
bit 2=Always 0
bit 3=Always 1
bit 4=shot(0 if pressed)
bit 5=left(0 if pressed)
bit 6=Always 0
bit 7=Always 0
[OUT]Shift Value

*** Port 3
[IN]Shifted Bitmap
        Port3=Port4<<(8-(Port2 & 7))
        ex. LD a,3
                OUT (2),a
                LD a,10110011b
                out (4),a
                in a,(3) ; reg a is 10011000b
[OUT]Sound
 bit 0=UFO
 bit 1=Shot
 bit 2=???
 bit 3=Hit
 bit 4=???
 bit 5=???
 bit 6=???
 bit 7=???

*** Port 4
[OUT]Bitmap

*** Port 5
[OUT]???

*** Port 6
[OUT]???

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Received on Mon May 08 14:35:44 2000