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Each mnemonic maps directly to a machine instruction code, known as an opcode. Some mnemonics map to more than one opcode, however the instruction's operand types will determine which specific opcode will be generated.
IP is incremented after fetch of instruction opcode. Specifically, IP is incremented by the number of opcode bytes.
3 for opcode fetch, 1 for opcode decode, 3 for operand fetch, and 3 for opcode store, for a total of 10, not including wait states.
three
i) Instruction code deals only with mnemonics and its corresponding opcode but data code refers to your data like 10h which is always of 8 bits or a particular address say 8080h which is of 16 bits. ii) Data is your input to the instruction but an opcode is native to your machine. iii) Data is user specific instruction while opcode is machine specific instruction iv) You can alter data code but you cannot modify an instruction opcode.
The process of transferring instruction codes from memory location to instruction queue register is called opcode fetch.
The instruction opcode is a type of data contained in memory, pointed to by the PC (Program Counter) register.
The microprocessor uses an opcode fetch cycle for every instruction because it has to know the opcode in order to execute it, and that is located in memory.
Summary − So this instruction XCHG requires 1-Byte, 4-Machine Cycles (Opcode Fetch) and 4 T-States for execution as shown in the timing diagram.
What is difference between oppress code and operend
Instructions are a given way of following things. They are given in a specific order so the outcome comes out as it was supposed to be in the beginning.
an opcode (operation code) is the portion of a machine language instruction that specifies the operation to be performed. Their specification and format are laid out in the instruction set architecture of the processor in question (which may be a general CPU or a more specialized processing unit). Apart from the opcode itself, an instruction normally also has one or more specifiers foroperands (i.e. data) on which the operation should act, although some operations may have implicit operands, or none at all. There are instruction sets with nearly uniform fields for opcode and operand specifiers, as well as others (the x86architecture for instance) with a more complicated, varied length structure.by: HerLoyd