Reading advice for compiler RunTime environment

Hi,

I have a sort of working Pascal compiler up and running.
It used to be an old research project of mine, which never really made it
out since I started to play ISP. The last build was done in the COFF area,
and I've found that things have somewhat changed...

Small programs are working, because I've made the main pascal program look
like a C-main routine. Perhaps not quite needed. But for instance, debugging
is totally non existant

So I'm looking for hints to read to catch up on these matters,

Thanx,
--WjW