I will write a an article on sidreloc at some other time. The command line tool sidreloc which is installed by DUST can be used to move the SID so init address and play routine address can be adjusted to what makes sense for your demo. A very common init address for SIDs is $1000 and for the playback routine $1003. That information is encoded within the SID. Do do either, we need to know the start address of the initialization routine and the start address of the replay routine.
First we need to initialize the music replay routine and then we need to trigger the actual music player routine with every screen refresh. Once we loaded the resource, how do we playback the SID? This is a two-step process. Luckily the !bin command lets us remove that extra information. Those SIDs come with a special header with some extra information for various cross platform music players which we need to remove when importing the file into our codebase. It also allows for a few parameters we need to work with SID files as provided on the net, e.g.
!bin loads a file from your harddisk into your C64 code. This instruction is once again a very handy pseudo opcode by ACME. With * = address_music we therefor tell ACME that the next instruction should be put in memory at $1000. I already set up a symbol earlier in init_symbols.asm which assigns $1000 to the symbol address_music. For this we need to specify a loading address, that is where is the SID stored in memory.
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