Register access: R-type

Components

Register file: 32 registers

ALU: performs arithmetic/logical

operations

Fig. 5.7

Register read

Instruction gives addresses of 2 read registers and 1 write register to register file

2 data read values are given by register file to inputs of ALU

R-type operation

3 ALU operation control bits are used to determine what operation is required

ALU result is returned to write data input of register file

ALU also has an output called Zero (indicates whether result of operation equals 0)

Note that RegWrite control input is used to determine if result is written

to the write register