... if this suits your purpose and if you can make the linker to pass the symbols around properly.

In SDCC, there is also an option to pass variables via stack, either internal or external (dependent on the model used); and generally, you can always write the routine call itself, together with the parameter handling, in the inline assembler (then how and where will you exactly pass the parameters is entirely upon you), although for this, Andy will certainly throw a couple of "-1 Don't In C" at me... :-)

JW

PS. Sorry I didn't notice that the example was already written with the parameter passing in memory...