Leveling floorboards

[Molebob]

The floor in one of my bedrooms has a significant hump to it. It can be seen in the centre of this photo.



I considered cutting the floorboards along the wall but I suspect that the internal block wall to the right is actually just resting on them. Not quite sure how to proceed.

 

[tomfe]

You can see where the josts run, the cuts and the nails will show you, cut out a section or lift any which are already cut and see what's making the boards do that.