Hint: Use X$\_(0),$X$1$ as arguments and X $2$ as return value, according to the convention for procedure calling.

Ex: If the values of X$19$ and X$20$ are initialized in the simulator as:

the result is stored in X$21$:

Code given:

ADDI X$28,$ XZR$,$ #$1000//$ Assume Stack memory starts at $1000.$ Do not modify.

$//$ Procedure Main $($Do not modify$)$

Main:

ADD X$0,$ XZR$,$ X$19$

ADD X$1,$ XZR$,$ X$20$

BL Sum

ADD X$21,$ X$20,$ X$19$

ADD X$21,$ X$21,$ X$2$

B End

$//$ Procedure Sum

Sum:

$//$ Type your code here.

$//$ Procedure Dif $($Do not modify$)$

Dif:

SUB X$2,$ X$1,$ X$0$

BR X$30$

End: