If you post a complaint on error, it always helps to tell, WHAT is the error.

Now you are about to use the most memory-expensive combination - all functions reentrant (--stack-auto) and large model. Note, that large model implies external RAM to have connected - is your system set up so?

For this combination, you need to compile the whole library yourself. You may omit the --stack-auto for the first attempts, as you don't have any function which needs to be reentrant at the moment. The large model libraries come precompiled with standard SDCC installation.

Note also the existence of less expensive variants of printf, e.g. printf_fast_f.

A final note, on a '51 you most likely DON'T want to use floats nor printf, anyway; so there's not much point in doing this as an excercise.

JW