They are exclusively used for the internal operation by the microprocessor . These registers are used either to store 8-bit of information in each W and Z registers or a 16-bit data in W, Z register pair with lower order 8-bits in Z and higher-order 8-bits in W register. Let us consider one example.
What is Z register?
To the LPM instruction the value contained in the Z register is interpreted as an offset measured in 8-bit bytes from the start of program memory . To convert the address of segtable to an offset usable with LPM it needs to multiplied by two.
What is the function of the register?
What Are Registers? A register is basically a storage space for units of memory that are used to transfer data for immediate use by the CPU (Central Processing Unit) for data processing . Also known as memory registers, they can actually form part of the computer processor as a processor register.
What is the role of WZ register in 8085 microprocessor?
The WZ register pair in the 8085 is used for temporary storage, but is invisible to the programmer . Internally, the WZ register pair is implemented like the other register pairs. The primary use of WZ is to hold operands from a two or three byte instruction until it can be used.
What is the function of temporary register?
A temporary register is the only register that can be read and written more than once in a single instruction . Each temporary register has single-write and triple-read access. Therefore, an instruction can have as many as three temporary registers in its set of input source operands.
What is the purpose of the Z bit?
| Bit Flag position Description | Z 6 Contains results of last arithmetic or compare result (0 for non-zero, 1 for zero). | 0 11 Indicates that an overflow has occurred in the most significant bit from an arithmetic operation. | P 2 | D 10 |
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What does the Z flag do?
The zero flag is typically abbreviated Z or ZF or similar in most documentation and assembly languages. Along with a carry flag, a sign flag and an overflow flag, the zero flag is used to check the result of an arithmetic operation, including bitwise logical instructions .
What is difference between register and memory?
The primary difference between register and memory is that register holds the data that the CPU is currently processing whereas , the memory holds the data the that will be required for processing. ... On the other hands, memory is referred as the main memory of the computer which is RAM.
What are the three types of registers?
- MAR Register. The full form of MAR is the memory address register. ...
- MDR. The full form of MDR register is a memory data register. ...
- MBR. The full form of MBR is the memory buffer register. ...
- PC. The full form of PC is the program counter register. ...
- Accumulator. ...
- Index Register. ...
- Instruction Register.
How does a register work?
Registers are temporary storage areas for instructions or data. ... Registers work under the direction of the control unit to accept, hold, and transfer instructions or data and perform arithmetic or logical comparisons at high speed .
Which is special purpose register?
A Special Function Register (or Special Purpose Register, or simply Special Register) is a register within a microprocessor , which controls or monitors various aspects of the microprocessor’s function.
What is the function of program counter?
The program counter, PC, is a special-purpose register that is used by the processor to hold the address of the next instruction to be executed . The PLA automatically updates the PC to point to the next instruction during the op-code decode cycle.
Is accumulator a special purpose register?
Special Purpose Registers. (a) Register A(Accumulator) – Register A is an 8-bit register used in 8085 to perform arithmetic, logical , I/O & LOAD/STORE operations. Register A is quite often called as an Accumulator. ... And the result of the arithmetic operation will be stored or accumulated in this register.
What is the difference between accumulator and register?
Register A is quite often called as an Accumulator. 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 difference between temporary and saved registers?
1 Answer. There is no difference between the temporary and saved variables in how they work. The difference is in how they are used, or rather, how they ought to be used.
Which register pair is used to indicate memory?
H and L register pair is used to act as memory pointer and it holds 16 bit address of memory location.
