This is an Arduino puzzle, I have to write in Atmel AVR Aseembly code , with registers etc.. I have to write the assembly code for this function

int addInt8ToInt(int8_t num1, int num2): Adds an 8-bit signedvalue to a 16-bit signed value and returns a 16-bit signed result. To do this properly, you should convert the 8-bit argument to a 16-bit argument before performing the addition.

this is what it gives me to start:

.global addInt8ToInt int8ToInt:

Thank you in advance !