General Register Organization:- This Architecture is used by most modern computer processors.
Any of the registers can be used as a source or destination for computer operation.
In a basic computer, there is only one general-purpose register, the AC.
In modern CPUs, there are many general-purpose registers.
It is advantageous to have many registers, as data transfer between registers is fast.
Ex- ADD R1, R2, R3
MOV R1, R2
Multiplexer A selector (SELA) places the content of R2 into bus A.
Multiplexer B selector (SELB) places the content of R3 into bus B.
ALU operation selector (OPR) to provide arithmetic addition A+B.
Decoder destination selector (SELD) to transfer the content of O/P bus into R1.
Control Word:- Combined value of 14 binary inputs.
14-bit control word when applied to selection input specifies a particular micro-operation.
When SELA OR SELB=000, multiplexer selects external input data.
When SELD=000, no destination register is selected but contents of output bus are avail in external output.
ALU:- In addition to arithmetic operations, it also does logic operations, like shift operations, transfer, increment, complement, etc.