Atari PC3 GEM mouse problem

[User64]

I tried running GEM on the Atari PC3 (The version of Gem designed for the PC3). I used the serial mouse option and it did not work. It might be because the PC3 has a unique connector that GEM is expecting the mouse to be attached to. I can provide more information if it is needed. Hopefully this post is not to late

[JohnElliott]

The Atari GEM distro is configured for an INT 33h mouse (usually provided by MOUSE.COM / MOUSE.SYS, unless the Atari BIOS has this built in). Easiest thing to do is probably to load a MOUSE.COM that knows about serial mice. Alternatively you can patch IBMEHFP6.SYS at offset 83C8h. It currently has 0F 02 -- change the first byte to 00 for COM1, 01 for COM2, and the second byte to 01 for Mouse Systems or 03 for a (serial) Microsoft mouse.