Test_series

Question

can anybody solve this ?

It_is_give_that

MOV_R1,#5600 will take 12 bytes because opcode size(3) * word size ( 4)

but my doubt is why they dont take into consideration size of operand

Answer 1

Program Counter holds the address of the next instruction to be fetched . Hence, size of the operand is not considered in this calculation. I am 80% sure about this reason of mine. Someone please correct if I am wrong.

Answer 2

From opcode size, they just wanted to convey the no of words required in memory to store that particular instruction.

Depending upon the size of the operands, each opcode demands its own amount of memory while storing the instruction in memory.

Since here first instruction needs 3 words so it is allocated accordingly, 3*4 bytes=12 bytes

Similarly, all the way down to "Halt" we need a total of (3+3+1+1+1+4+1)14 words in memory to accommodate this piece of code.

And so the memory addresses will get along and add up more 14*4=56 bytes in initial memory address i.e 1500.Since program counter stores memory address of next instruction to be executed, we'll have next instruction at 1500+56=1556.