What are the ways to clear the accumulator?
What are the ways to clear the accumulator?
SUB A is another one-byte instruction. It subtracts accumulator value from the accumulator. The XRA A and SUB A both are one-byte instruction, but as XRA A is logical, it performs faster than the other. So XRA A is best for clearing/resetting Accumulator content than other three instructions.
Which of the following instruction is used to clear accumulator?
Discussion Forum
| Que. | Which one of the following instruction may be used to clear the accumulator content irrespective of its initial value? |
|---|---|
| b. | ORA A |
| c. | SUB A |
| d. | MOV A, 00H |
| Answer:SUB A |
Which does not clear the accumulator?
This discussion on The instruction, that does not clear the accumulator of 8085, isa)XRA Ab)ANI 00Hc)MVI A, 00Hd)None of the aboveCorrect answer is option ‘D’.
Which instruction can be used to clear the contents of register by XORing with itself?
The XOR Instruction XORing an operand with itself changes the operand to 0. This is used to clear a register.
What is the content of the accumulator?
In 8085 Instruction set, STA is a mnemonic that stands for STore Accumulator contents in memory. In this instruction, Accumulator 8-bit content will be stored in a memory location whose 16-bit address is indicated in the instruction as a16. This instruction uses absolute addressing for specifying the destination.
Which Interrupt has the highest priority?
Explanation: The Non-Maskable Interrupt input pin has the highest priority among all the external interrupts. Explanation: TRAP is the internal interrupt that has highest priority among all the interrupts except the Divide By Zero (Type 0) exception.
Why do interrupts have priorities?
Priority Interrupt The system has authority to decide which conditions are allowed to interrupt the CPU, while some other interrupt is being serviced. When two or more devices interrupt the computer simultaneously, the computer services the device with the higher priority first.
Which is highest priority interrupt on 8085?
TRAP
How can multiple interrupts be serviced by setting priorities?
Multiple interrupts may be serviced by assigning different priorities to interrupts arising from different sources. This enables a higher-priority interrupt to be serviced first when multiple requests arrive simultaneously; it also allows a higher-priority interrupt to pre-empt a lower-priority interrupt.
What is the purpose of interrupts?
1. Role of Interrupts. Interrupts are signals sent to the CPU by external devices, normally I/O devices. They tell the CPU to stop its current activities and execute the appropriate part of the operating system.
What are the types of interrupts?
Types of Interrupt
- Hardware Interrupts. An electronic signal sent from an external device or hardware to communicate with the processor indicating that it requires immediate attention.
- Software Interrupts.
- Level-triggered Interrupt.
- Edge-triggered Interrupt.
- Shared Interrupt Requests (IRQs)
- Hybrid.
- Message–Signalled.
- Doorbell.
How many interrupts are there in 8085?
8
Which stack is used in 8085?
LIFO
How many instructions are there in 8085?
74 instructions
How many data and address lines are there in 8085?
16 address line
Which register is 16 bit?
A 16-bit Data Segment register or DS register stores the starting address of the data segment. Stack Segment − It contains data and return addresses of procedures or subroutines. It is implemented as a ‘stack’ data structure. The Stack Segment register or SS register stores the starting address of the stack.
Who designed 8085?
Intel
Why is it called 8085?
The Intel 8085 (“eighty-eighty-five”) is an 8-bit microprocessor produced by Intel and introduced in March 1976. It is a software-binary compatible with the more-famous Intel 8080 with only two minor instructions added to support its added interrupt and serial input/output features.
Is 8085 a RISC or CISC?
So we can say our processor 8085 is a RISC and controller 8051 is a CISC. Reduced instruction set Computer. It is a type of microprocessor that has been designed to carry out few instructions at the same time.
How many register pairs are there in 8085?
six registers
What are the allowed register pairs of 8085?
The 8085 has six general-purpose registers to store 8-bit data; these are identified as- B, C, D, E, H, and L. These can be combined as register pairs – BC, DE, and HL, to perform some 16-bit operation. These registers are used to store or copy temporary data, by using instructions, during the execution of the program.
Why stack pointer is 16 bit?
The program counter always contains a memory address (the location of the next machine instruction to fetch). So, both the program counter and the stack pointer must be 16 bits wide. Because the 8085 addresses 16 bits of address, and both the PC and the SP are registers that hold addresses.
Is accumulator a special purpose register?
Special Purpose Registers. An accumulator is a register for short-term, intermediate storage of arithmetic and logic data in a computer’s CPU (Central Processing Unit). In an arithmetic operation involving two operands, one operand has to be in this register.
What is the purpose of accumulator register?
An accumulator is a register for short-term, intermediate storage of arithmetic and logic data in a computer’s CPU (central processing unit).
What is the purpose of accumulator?
Accumulator is a pressure vessel for storing hydraulic pressure in it utilizing compressible and decompressible nature of nitrogen gas. So, it can be said that the accumulator has a similar function to the rechargeable electrical battery. In electricity, electrical energy is stored to the battery.
What is the difference between accumulator and register?
Register memory is the fastest memory available to the CPU. It’s is used to store information which is immediately needed by the processor. Therefore all the information to & from the processor goes via registers. Accumulator is a register which stores the intermediate results for large computations.