Register file: black box

Encoding for the instruction

000000

00010

00011

00001

00000

100000

b31-26

b25-21

b20-16

b15-11

b10-6

b5-0

opcode

$rs

$rt

$rd

shamt

function

Good ISA design helps:

Can get the desired bits for the source registers without doing much decoding.

Once the ten bits are sent from the IR as ADDRESS inputs to the register file,

the register file produces 64 bits of DATA output

Implementation as a black box:

Notice that we haven't said anything yet about

HOW the address inputs

are turned into data outputs