Why is the program counter register 16 bits instead of 8?
8 bit address can only locate/address 256 memory locations. 16 bit address can locate up to 64kb. And hence the need of 16 bit PC & SP instead of 8 bits. Data registers or data bus could be just 8 bits still.
Why is the program counter in 8085 microprocessor 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 are the 16 bit registers available in 8085 microprocessor?
In 8085 microprocessor, the 16-bit registers used are:
- Stack pointer and accumulator.
- Program counter and accumulator.
- Stack pointer and program counter.
- Accumulator, stack pointer and program counter.
What are SP and PC register in 8085 MPU?
But in the complete programmer’s view of 8085, there are two more special purpose registers, each of 16-bit width. They are the stack pointer, SP, and the program counter, PC. The Stack Pointer register will hold the address of the top location of the stack.
What is SP register?
The Stack Pointer (SP) register is used to indicate the location of the last item put onto the stack. When you PUT something ONTO the stack (PUSH onto the stack), the SP is decremented before the item is placed on the stack.
Which flag is not used in programming?
Discussion Forum
| Que. | Which flag of the 8085’s flag register is not accessible to programmer directly? |
|---|---|
| b. | Carry flag |
| c. | Auxiliary carry flag |
| d. | Parity flag |
| Answer:Auxiliary carry flag |
Is a flag a Boolean?
A Flag is a boolean variable that signals when some condition exists in a program. When a flag is set to true, it means some condition exists When a flag is set to false, it means some condition does not exist.
Why is a flag register necessary?
The wider registers retain compatibility with their smaller predecessors. The fixed bits at bit positions 1, 3 and 5, and carry, parity, adjust, zero and sign flags are inherited from an even earlier architecture, 8080 and 8085.
How many flags are there in 8086?
9 flags
Is Al a 16-bit register?
16-bitEdit The registers found on the 8086 and all subsequent x86 processors are the following: AX, BX, CX, DX, SP, BP, SI, DI, CS, DS, SS, ES, IP and FLAGS. These are all 16 bits wide. So AX = AH (high 8-bit) and AL (low 8-bit).
Which of the following is 16-bit register Mcq?
Explanation: Program counter : It is a 16-bit register used to store the memory address location of the next instruction to be executed. 7.
What is the function of index register?
An index register in a computer’s CPU is a processor register or assigned memory location used for modifying operand addresses during the run of a program. This proved useful for doing vector/array operations and in commercial data processing for navigating from field to field within records.
How many types of registers are there?
There are two types of registers. Some registers are internally in the processor while the other one is user-accessible. These two types of registers differ in their accessibility to computer architecture.
What is stored in index register?
An index register is a circuit that receives, stores, and outputs instruction-changing codes in a computer. This circuit is also called an address register or a register of modifications. A register can hold an instruction, a storage address, or any kind of data.