What is the instruction decoder?

The instruction decoder is the circuit that decodes an opcode. As an example, on the 6502 CPU, the opcode for the CLI (clear interrupt) instruction is 01011000 in binary. The CPU receives this as a set of digital logic signals on the data bus. read more

Instruction decoder takes bits stored in the instruction register and decodes it and tells to CPU what it need to do for it and enable the components for the operation. Simply, instruction decoder is like a dictionary. It tells the meaning of the instruction. read more

CISC Instruction Decoder Decoding a CISC instruction word is much more difficult than the RISC case, and the increased complexity of the decoder is a common reason that people cite when they choose to use RISC over CISC in their designs. read more

Instruction decoder The instruction decoder of a processor is a combinatorial circuit sometimes in the form of a read-only memory, sometimes in the form of an ordinary combinatorial circuit. Its purpose is to translate an instruction code into the address in the micro memory where the micro code for the instruction starts. read more