What does the program counter register do?
A program counter is a register in a computer processor that contains the address (location) of the instruction being executed at the current time. As each instruction gets fetched, the program counter increases its stored value by 1. Within a computer, an address is a specific location in memory or storage.
What does the program counter register keep track of?
The program counter (PC) is a register that manages the memory address of the instruction to be executed next. The address specified by the PC will be + n (+1 for a 1-word instruction and +2 for a 2-word instruction) each time one instruction is executed.
What is program counter register with example?
A program counter is a register in the CPU containing the address of the next instruction to be executed from memory. For example, when your computer is turned on, a signal places the decimal number F000 into the CPU. This action tells the computer to look at the first instruction on the motherboards flash memory chip.
Is program counter a 8 bit register?
The most widely used registers of the 8051 are A (accumulator), B, R0-R7, DPTR (data pointer), and PC (program counter). All these registers are of 8-bits, except DPTR and PC.
What is the function of program counter in 8051 microcontroller?
Program Counter (PC) The Program Counter (PC) is a 2-byte address which tells the 8051 where the next instruction to execute is found in memory. When the 8051 is initialized PC always starts at 0000h and is incremented each time an instruction is executed.
What is the purpose of program counter in 8085 microprocessor?
Program Counter: This register is used to sequence the execution of the instructions. The function of the program counter is to point to the memory address from which the next byte is to be fetched.
What is program counter in 8085 microprocessor?
PC contains that very memory address from where the next instruction is to be fetched for execution. Suppose the PC contents are 8000H, then it means that the 8085 Desires to fetch the instruction Byte at 8000H.
What is true about program counter?
What is true about Program counter? A. It is an 8-bit register, which holds the temporary data of arithmetic and logical operations. Explanation: Program counter : It is a 16-bit register used to store the memory address location of the next instruction to be executed.
Why is program counter a 16-bit register?
The program counter acts as a pointer to the next instruction to be executed and always contains the 16-bit address of the memory location of next instruction. It is a 16 bit register as 8085 has 16 address lines.
What does a register store?
A register may hold an instruction, a storage address, or any kind of data (such as a bit sequence or individual characters). The effective address of any entity in a computer includes the base, index, and relative addresses, all of which are stored in the index register. A shift register is another type.
What is the purpose of PC?
At home, PCs are mainly used for multimedia entertainment, playing PC games, accessing the Internet, etc. Even though PCs are intended to use as single-user systems, it is normal to connect them together to create a network, such as a local area network (LAN).
What is the program counter in a computer?
The program counter ( PC ), commonly called the instruction pointer ( IP) in Intel x86 and Itanium microprocessors, and sometimes called the instruction address register ( IAR ), the instruction counter, or just part of the instruction sequencer, is a processor register that indicates where a computer is in its program sequence.
What is the difference between program counter and instruction register?
The program counter (PC) holds the address of the next instruction to be executed, while the instruction register (IR) holds the encoded instruction. Upon fetching the instruction, the program counter is incremented by one “address value” (to the location of the next instruction).
What happens to the program counter as each instruction gets fetched?
As each instruction gets fetched, the program counter increases its stored value by 1. After each instruction is fetched, the program counter points to the next instruction in the sequence.
How does the CPU execute the program counter?
Now the CPU can execute the instruction and increment the program counter by . Similarly, we can see the instruction is stored in different addresses in memory. Hence, when the program counter is , the CPU fetches all the parts in the instruction register and execute the instruction :