A: ALL computer have an I/O and have interrupt signals these signal are there to service whatever is requesting a service. A printer request for instance or a USB device the processor will wait until the service is completed unless it is released. lesson to learn the I/O is the pace of speed not the speed of the CPU which usually loaf waiting for interrupts to be finished. Fast I/O buss means a fast computer.
an instruction cycle may consist of a number of machine cycles.
No. Generally, one instruction in a high level language corresponds to many instructions in machine language.
Assembly language to machine code translation is a "one to one" translation process, as every individual instruction expressed in the assembly language corresponds to exactly one machine instruction. Note this does not hold for pseudo instructions or expanding macros, which are supported by some assemblers.
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.
Depending on the particular microprocessor, a machine cycle is the fetch or store of one (typically, one byte) native word. In the 8085, this is a byte fetch or store, plus the overhead in decoding and processing the instruction. In this case, the first machine cycle is four clock cycles, or T states, and subsequent machine cycles are three clock cycles, although certain instruction sequences, such as DAD, require two extra clock cycles.
No. Pipeline processors are faster because they do not have to wait to fetch the next instruction, because the next instruction was "pre-fetched" already.
pipelining
Fetch Decode Execute. This is the cycle that processors will follow. Fetch the Instruction, Decode it into machine code, Execute the commands
Each time the CPU executes an instruction, it takes a series of steps. The complete series of steps is called a machine cycle. A machine cycle can be divided into two smaller cycles. These are instruction cycle and execution cycle. Instruction cycle: In instruction cycle CPU takes two steps-- 1. Fetching: Before the CPU can execute an instruction, the control unit must retrieve or fetch a command or data from the computer's memory. 2. Decoding: Before a command can be executed, the control unit must decode the command into instruction set. Execution cycle: In execution cycle CPU also takes two steps-- 1. Executing: When the command is executed, the CPU carried out the instructions in order by converting them into macrocode. 2. Storing: The CPU may be required to store the result of an instruction in memory.
comparing, decoding, executing, nd fetching
A pseudo-op is an assembly language instruction that specifies an operation of the assembler i.e about the base register & its contents e.g. USING instruction. On the other hand, a machine-op instruction. That represents a machine instruction to the assembler e.g. BR instruction is a machine-op instruction
an instruction cycle may consist of a number of machine cycles.
It depends on whether the machine code is one, two, or three bytes long, and on whether or not the instruction transferred control to another location. In the case of a non-jump single byte instruction, the PC will have a value of 2060H after the instruction is complete, and it will be 2061H or 2062H after a two or three byte instruction. In the case of a jump, call, or interrupt, the PC will depend on the instruction.
To add a new machine language instruction to an processor instruction set, you need to replace the microcode of the processor.
HLT
No. Generally, one instruction in a high level language corresponds to many instructions in machine language.
fetch decode execute and store in that order.... i do not know the description of each stage i need the answer to that myselfmachine cycle is also called instruction cycleCPU performs following steps to execute an instructionFetchDecodeExecuteStoringFetchload instruction from the memory to execute.this operation performed by control unit.Decodedetermine what the instruction is telling the computer to do,and what operation should be taken.Executeafter decoding and getting the required result,CPU finally execute instruction by ALU(arthematic logic unit).Storingthe process of writing the result to memory is called storing or the process of storing the generated result to the main memory.