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When an interrupt occurs, the address following the current instruction is stored on the stack.
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.
Instruction codes are typically stored as binary data in memory cells in a computer system. Each instruction is represented by a sequence of bits that the processor can interpret and execute. The specific format and organization of the instruction code within the memory cells are determined by the computer architecture and the encoding scheme used by the processor.
the differebce between three address instruction and two address instruction is three adresss instructoion two address instruction 1) here 3 oprarend fields are used 1) here 2 oprerand fields are used 2) the result is stored in 3rd operand 2) here the result is stored in 2nd oparend
instruction stored in the gene in the form genetic code.
The place where the instructions are coded and stored is called the BIOS. The BIOS is an acronym of Basic Input Output System.
Flag register part of psw
computer
The ADD M instruction in assembly language is used to add the value stored at the memory address specified by the operand M to the accumulator (usually denoted as A). After the addition, the result is stored back in the accumulator. This instruction facilitates arithmetic operations involving data stored in memory, enabling the processor to perform calculations using both immediate and memory-resident values.
Auxillary memory is required so that set of instruction given first stored in temorary memory which can be edited & then can be stored
CPU
Fetch Execute Cycle A more complete form of the Instruction Fetch Execute Cycle can be broken down into the following steps: 1. Fetch Cycle 2. Decode Cycle 3. Execute Cycle 4. Interrupt Cycle 1. Fetch Cycle The fetch cycle begins with retrieving the address stored in the Program Counter (PC). The address stored in the PC is some valid address in the memory holding the instruction to be executed. (In case this address does not exist we would end up causing an interrupt or exception).The Central Processing Unit completes this step by fetching the instruction stored at this address from the memory and transferring this instruction to a special register - Instruction Register (IR) to hold the instruction to be executed. The program counter is incremented to point to the next address from which the new instruction is to be fetched. 2. Decode Cycle The decode cycle is used for interpreting the instruction that was fetched in the Fetch Cycle. The operands are retrieved from the addresses if the need be. 3. Execute Cycle This cycle as the name suggests, simply executes the instruction that was fetched and decoded