When selecting a texture it is similar to C but is far more simplified. Normally, in C you would do the following:

#define Texture 0

In asm this translates to the following:

mov R7, 0
out GPU_SelectedTexture, R7

What is happening in the above snip of code is that we are putting in our number ID for our texture into register 7 and then feeding R7 into the GPU_SelectedTexture.

After you have successfully selected your texture you need to select a region inside your texture file. To accomplish this in asm you are repeating similar steps as to selecting a texture. Here is a sample of what that would look like:

mov R7, 1
out GPU_SelectedRegion, R7

Similarly to above, we are putting the id for a region into R7 and then feeding R7 into GPU_SelectedRegion.

To display your regions you need 2 things. Firstly, you need to say where you want to display the region. That is done by putting in values for X and Y into 2 different registers. Here is what that looks like:

mov R2, 20 ; X coordinate
mov R3, 40 ; Y coordinate

Implemented from scratch, in assembly:

• select the loaded texture
• select 4 objects (regions) to display
• display the object on the screen, allowing for its control via the gamepads
  • each gamepad direction should display a different object
• implement bounds checks on the screen edges, preventing the object from moving off the screen