so I should see a viewport not starting in the corner, but 100 from the corner and 100 pixels wide/tall. But the (x,y), the first two components of this function don't seem to do anything, can somone test this really quick?
mmhhh.... could you please play with the Viewport / Screen Offset register? See glViewport.c, registers 76 and 77. Maybe we need to add x and y there. Maybe also at the viewport center point (register 69/70). Can you please report your results?