Zerobss will clear memory - the source file is in libsrc\common\zerobss.s
copydata will set up the initialized data area - the source file is libsrc\common\copydata.s

Libinit and libdone will run any initialization code required by an included library. I'm not sure if any cc65 system libraries use this. Some of the platform specific libraries do use it. My graphics library used them in the SBC3 target as well. The source file is libsrc\runtime\condes.s

Hope this helps.

Daryl

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The logic behind those routines is defined in cfg and well explained in here:
http://www.cc65.org/doc/ld65-5.html

Axel.