Data Transfer Instruction

What is the data transfer instruction? Give example.

Data transfer instructions move data between registers or between memory and registers. For example:

• String Forms:

movsb ;move string byte by byte

movsw ;move string word by word

EXAMPLE:

Movsb es, ds ;Copies 8 bits at DS:SI to ES:DI

• New String Form (386+):

movzx ;move string with zero extended

movsx ;move string with sign extended

EXAMPLE:

movsx cx, al ;cl get al

movzx cx,al ;cl gets al

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difference between hardware and software interrupts in 8085 microprocessor

Differentiate between hardware interrupts and software interrupts of 8085.

• The software interrupt is initiated by the main program, but the hardware interrupt is initiated by an external device.
• In 8085, the software interrupt cannot be disabled or masked but the hardware interrupt except TRAP can be disabled or masked.

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CMA instruction in 8085

Explain the execution of the instruction CMA in 8085.

CMA - Complement Accumulator

The Complement Accumulator (CMA) instruction provides a 1’s complement of the 8 bits in the A register, i.e the 1’s are set to 0’s and the 0’s are set to 1’s.

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List four interrupts of 8085 microprocessor

List four interrupts of 8085.

INTERRUPTS OF 8085

• INTR,
• RST7.5
• RST6.5
• RST5.5

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instruction format of 8085 microprocessor

What is the instruction format of 8085.

The instruction set is grouped into the following formats:

	Task Op		code
1 BYTE	Copy the contents of the accumulator in the register C.		MOV C,A
2 BYTE	Load an 8-bit data byte in the accumulator		MVI A,data
3 BYTE		Transfer the program sequence to the memory location 2085H.	JMP 2085H

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