In an instruction execution pipeline, the earliest that the data $$TLB$$ (Translation Look aside Buffer) can be accessed is

The following code is to run on a pipelined processor with one branch delay slot
$$\eqalign{ & {{\rm I}_1}:\,\,ADD\,\,{R_2}\,\, \leftarrow \,\,{R_7} + {R_8} \cr & {{\rm I}_2}:\,\,SUB\,\,\,{R_4}\,\, \leftarrow \,\,{R_5} - {R_6} \cr & {{\rm I}_3}:\,\,ADD\,\,{R_1}\,\, \leftarrow \,\,{R_2} + {R_3} \cr & {{\rm I}_4}:\,\,STORE\,\,Memory\,\,\left[ {{R_4}} \right]\,\, \leftarrow \,\,{R_1} \cr & BRANCH\,\,to\,\,Label\,\,if\,\,{R_1} = = 0 \cr} $$

Which of the instructions $${{\rm I}_1},\,{{\rm I}_2},\,{{\rm I}_3}$$ or $${{\rm I}_4}$$ can legitimately occupy the delay slot without any other program modification?

For inclusion to hold between two cache levels $$L1$$ and $$L2$$ in a multilevel cache hierarchy, which of the following are necessary?

$$1.$$ $$L1$$ must be a write-through cache
$$2.$$ $$L2$$ must be a write-through cache
$$3.$$ The associativity of $$L2$$ must be greater than that of $$L1$$
$$4.$$ The $$L2$$ cache must be at least as large as the $$L1$$ cache

In the $$IEEE$$ floating point representation the hexadecimal value $$0\, \times \,00000000$$ corresponds to