No, that won't work: you'll get a duplicate definition (or similar) error from the Linker.

You need to understand the difference between definitions and declataions:

A declaration just tells the Compiler that a symbol exists - its type, size, etc;

A definition is what actually allocates space in memory, or creates executable code.

You have already made the definition in your assembler, so you just need to provide a declaration in 'C':

You need to make your assembler symbol PUBLIC and provide a suitable extern declaration in 'C'