Sample $4$:

add $t$0,$ $zero, $zero

addi $$a0,$ $zero, $21$

loop: beq $$a0,$ $zero, end

add $ to$,$ $ t$0,$ $$a0$ addi

$$a0,$$$a0,-3$

j loop

end:

For beq $a$0,$ $zero, end give the binary value of the offset field. Briefly explain.