What is DCR instruction?

What is DCR instruction?

In 8085 Instruction set, DCR is a mnemonic, which stands for ‘DeCRement’ and ‘R’ stands for any of the following registers, or memory location M pointed by HL pair. Also we can say it will subtract 1 from the register R content. And the decremented value will be stored on to the register R itself.

Does DCX affect zero flag?

DCX decrements the contents of the specified register pair by one. DCX affects none of the condition flags.

What is the meaning of an instruction INR H?

In 8085 Instruction set, INR is a mnemonic that stands for ‘INcRement’ and ‘R’ stands for any of the following registers or memory location M pointed by HL pair. R = A, B, C, D, E, H, L, or M. This instruction is used to add 1 with the contents of R. So the previous value in R will get increased by amount 1 only.

How does Ana instructions work?

In 8085 Instruction set, ANA is a mnemonic, which stands for “ANd Accumulator” and “R” stands for any one of the following registers, or memory location M pointed by HL pair. This instruction is used to AND contents of R with Accumulator’s content. It occupies only 1-Byte in memory.

What is the difference between DCR and DCX instruction?

As if the initial content of BC register pair be 2000H then after DCR C instruction execution it would be 20FFH not 1FFFH.So, basically, DCX instruction decrements a 16-bit quantity, whereas DCR decrements an 8-bit quantity.

What is difference between INR and INX instruction?

What is the difference between INR and INX instruction? INR instruction increases the result of a designated register by 1. IXR instruction increases the result of the whole register pair by 1. For example, in the HL register, INX H will increase the value of the location being pointed by whole HL pair by 1.

What does the instruction dad H stand for?

Here, DAD is a mnemonic, which stands for Double ADd and also rp stands for any one of the following register pairs as mentioned below. rp = BC, DE, or HL. As rp can have any of the three values, there are three opcodes for this type of instruction. It occupies only 1-Byte in memory. Mnemonics, Operand.

What is the difference between DCR and DCX?

What is the result of INX H instruction?

And thus the result of the incremented content will remain stored in rp itself. Though it is an arithmetic instruction, note that, flag bits are not at all affected by the execution of this instruction. A register pair is generally used to store 16-bit memory address….Instruction type INX rp in 8085 Microprocessor.

Mnemonics, Operand	Opcode(in HEX)	Bytes
INX H	23	1

Which instruction does not affect the carry flag?

NOT instruction does not affect any flags! NEG instruction affects these flags only: CF, ZF, SF, OF, PF, AF. NOT – Reverse each bit of operand.

What are arithmetic instructions?

Arithmetic Instructions are the instructions which perform basic arithmetic operations such as addition, subtraction and a few more. In 8085 microprocessor, the destination operand is generally the accumulator. In 8085 microprocessor, the destination operand is generally the accumulator.

What is the operation of DCX H instruction?

Microprocessor8085. In 8085 Instruction set, DCX is a mnemonic that stands for “DeCrementeXtended register” and rp stands for register pair. And it can be any one of the following register pairs − rp = BC, DE, or HL. This instruction will be used to subtract 1 from the present content of the rp.

How does DCR your decrease the content of register R?

This instruction is used to decrease the content of register R. Also we can say it will subtract 1 from the register R content. And the decremented value will be stored on to the register R itself. As it is an arithmetic instruction, so all flags, except Cy flag, are affected depending on the result.

Which is an example of DCR your instruction?

As R can have any of the eight register values, so eight opcodes for this type of instruction are possible. It occupies only 1-Byte in memory. Let us consider DCR M is an example instruction of this type. It is a 1-Byte instruction. Let us consider HL register pair is having initial content of 16-bit address as 4050H.

What does DCR m and DCX m do?

DCR M (the content of memory location pointed by the HL pointer is decremented by 1.) 14. DCX: – decrement the register pair by 1. Eg: DCX H ( it decreases the memory location pointed by HL pair by 1. 15. DAA: – Decimal adjust accumulator.

What does DCR stand for in the 8085 instruction set?

Microprocessor 8085 In 8085 Instruction set, DCR is a mnemonic, which stands for ‘DeCRement’ and ‘R’ stands for any of the following registers, or memory location M pointed by HL pair. R = A, B, C, D, E, H, L, or M This instruction is used to decrease the content of register R.

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