2. How many times does the processor need to refer to memory when it fetches and

ID: 3863116 • Letter: 2

Question

2. How many times does the processor need to refer to memory when it fetches and executes an indirect-address- mode instruction if the instruction is

(a) a computation requiring a single operand

(b) a branch?

3. Suppose a computer using direct mapped cache has 2 40 bytes of byte-addressable main memory and a cache of 64 blocks, where each block contains 32 bytes.

(a). how many blocks pf main memory are there ?

(b) .what is the format of a memory address as seen by the cache, that is, what are the sizes of the tag,block and offset fields.

Explanation / Answer

Ans 2 : Assuming one word per instruction or operand, the solution is as below.

Computational type

Branch type

Fetch Instruction

Fetch effective address

Fetch effective address and transfer to PC

Fetch operand

3 memory references

2 memory references