What is the cumulative effect of executing these two instructions?

A$)$ "Read from unimplemented I$/$O port"

B$)$ "Read from uninitialized RAM Adress"

C$)$ "Assembly syntax"

D$)$ Read from uninitialized ROM Adress"

E$)$ Value of RegD is copied to Regx

F$)$ Value of Reg $x$ is copied to Reg D

G$)$ Value of Reg D is copied to Reg X

H$)$ Values of Reg D and Reg X are exchanged.