In the file https://github.com/MartinGalway/C64_music/blob/main/ocean_as...

> DSP

> not entirely sure what this one is... another variation of "Define Space" ? check back for the correct definition of this

It's probably 'displacement'. This worked together with ORG ('origin'). ORG specifies where in memory the code will run. DSP then moves the code the specified amount further along in memory, with the understanding that it will be moved back to the ORG address when it needs to run.

> DFC

> not entirely sure what this one is... define characters?

Same as DFM, but generates PETSCII instead of ASCII.