Constants in vcs.h

[Nostalgic]

The version of vcs.h that comes with DASM has constants representing various memory locations in the Atari 2600.

 

I noticed that it doesn't have constants representing the values that you can store in those locations.

 

For instance, vcs.h defines what CTRLPF is, but doesn't have a constant with a value of 1 for setting the playfield to reflected.

 

I found an old version of a vcs.h by Nick Bensema at https://web.archive.org/web/20110423060216/http://www.io.com/~nickb/atari/doc/vcs.h.  This has constants in it, such as PF_Reflect for reflected playfield, P_ThreeClose for three copies of a sprite close together, and J0_Right for first joystick moved to the right.

 

I'm curious as to why these, or something similar, hasn't been adopted in the files that come with DASM.  Or if there are constants that are widely used, what are they?

 

[+Andrew Davie]

1 hour ago, Nostalgic said:

 

I'm curious as to why these, or something similar, hasn't been adopted in the files that come with DASM.  Or if there are constants that are widely used, what are they?

 

 

No particular reason, except perhaps the register names were set in stone by original documentation, but names for the bit fields were not necessarily so.

Improvements/updates welcome.  It's a good idea that would make code more readable.