Has anyone written assembler functions that would stuff strings into arrays?

If someone would give me the basics of it, I'd love to write a set of low-level string functions for manipulating strings withing PBP arrays. Someone please help me get to first base and I'll run with it, posting the results as I go !

Just show me how to accomplish: MyArray = "Hi Blaine" via something like:

call stringassign MyArray, "Hi Blaine"

Then I'll try to write corresponding functions for mid, left, right, and concatenation. We'll debate, refine, and GO FORWARD CONQUERING!