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What processor begins fetching a second instruction before it completes the machine cycle for the first instruction?
Wiki User
∙ 10y ago
almost all modern computers do this (the exceptions are typically simple microcontrollers ). various methods can be used:
- prefetch
- pipelining
- caches
- etc.
One computer that I used that implemented prefetch (without pipelining, caches, or other mechanisms) to an extreme was the Delco Magic V implementation of the MIL-STD-1750A architecture. It had a prefetch unit with a FIFO buffer that could store roughly 20 instructions before they were needed by the address evaluation and operand read unit which had another FIFO buffer which could store roughly 20 instructions their operands and the address to store the results to before they were needed by the execution unitwhich had yet another FIFO buffer which could store roughly 20 results and the address to store those results tobefore they were needed by the memory storage unit. In all roughly 60 instructions could be held waiting to be processed between prefetch and storage of results to memory. Multiple levels of scoreboard synchronization logic were used to prevent the prefetch unit and address evaluation and operand read unit from accessing memory or registers pending modification by the memory storage unit or execution unit.
Wiki User
∙ 10y ago
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What parameters decide the size of data type for a processor?
Some bits of machine instruction code. Of course it is platform-dependent.
How many machine cycles do one byte instructions have?
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.
What is the difference between instruction cycle and machine cycle?
an instruction cycle may consist of a number of machine cycles.
One instruction in high level language corresponds to one instruction in machine language?
No. Generally, one instruction in a high level language corresponds to many instructions in machine language.
What Frees processors from having to wait for one instruction to complete the machine cycle before fetching the next?
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.
How do you add new machine language instruction to a processor intsruction set?
To add a new machine language instruction to an processor instruction set, you need to replace the microcode of the processor.
What frees processors from having to wait for one instruction to compleate the machine cycle before fetching the next?
pipelining
Are processors that use pipelining slower because they have to wait for one instruction to complete the machine cycle before fetching the next?
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.
What are the four distinct actions that a machine instruction can specify?
• The processor fetches the instruction from memory • Program counter (PC) holds address of the instruction to be fetched next • PC is incremented after each fetch • Fetched instruction loaded into instruction register
What is a micro-instruction?
microinstruction: An instruction that controls data flow and instruction-execution sequencing in a processor at a more fundamental level than machine instructions. Note: A series of microinstructions is necessary to perform an individual machine instruction.a micro instruction specifies one or more micro oprations for the system.
What parameters decide the size of data type for a processor?
Some bits of machine instruction code. Of course it is platform-dependent.
What are the four operations of the machine cycle?
comparing, decoding, executing, nd fetching
What is the Difference between machine op and pseudo op?
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
What is microoperation?
Microoperations are fundamental operations that can be performed by a digital computer's control unit at a very basic level, usually involving simple data manipulation or transfer tasks. These operations form the building blocks for more complex instructions and tasks executed by a computer's central processing unit (CPU). They are essential for controlling the flow of data and instructions within a computer's architecture.
Timing diagram of 8085?
Timing Diagram is a graphical representation. It represents the execution time taken by each instruction in a graphical format. The execution time is represented in T-states.Instruction Cycle:The time required to execute an instruction is called instruction cycle.Machine Cycle:The time required to access the memory or input/output devices is called machine cycle.T-State:The machine cycle and instruction cycle takes multiple clock periods.A portion of an operation carried out in one system clock period is called as T-state.MACHINE CYCLES OF 8085:The 8085 microprocessor has 5 (seven) basic machine cycles. They areOpcode fetch cycle (4T)Memory read cycle (3 T)Memory write cycle (3 T)I/O read cycle (3 T)I/O write cycle (3 T)Each instruction of the 8085 processor consists of one to five machine cycles, i.e., when the 8085 processor executes an instruction, it will execute some of the machine cycles in a specific order.The processor takes a definite time to execute the machine cycles. The time taken by the processor to execute a machine cycle is expressed in T-states.One T-state is equal to the time period of the internal clock signal of the processor.The T-state starts at the falling edge of a clock.
What is the definition of an ATM processor?
An ATM processor is an Automatic Teller Machine Processor, i.e. a machine that, when you insert a card, gives you means of exchange, or money.
How many machine cycles do one byte instructions have?
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.
