Oh guys come on, ASM is not needen for everything.
At least not for such a simple task.
First of all figure out the coordinates of your character.
This can be done by a "search unknown value" on initial and then go some steps and look for increasement.
Then go some steps back and look for decreasement.
Narrow this down till you get X and Y, or X,Y,Z in 3D based games.
Colission Detection often happens on a basis of Walking = 1, Colission = 0.
Sometimes it's the other way around you gotta test that with the game.
So walk around and search for 1. Run into a wall. Search for a decreasement of 1.
Or just the other way around. 0 and then increasement.
Can work. I always write walk through wall codes for PSX games like that.
Never had any problems with them.
Two ways for writing the code:
1. pretty one: locate the clipping routines and replace them with nop operations.
2. ugly and fast one: freeze the colission detector value to constantly walking. (Running into a wall will be interpreted as walking)