Microprocessor 8085 Data-transfer Instructions - Microprocessor

What are data transfer instructions? What are its functions?

Following is the table showing the list of Data-transfer instructions with their meanings.

Opcode
Operand
Meaning
Explanation
MOV
Rd, Sc
M, Sc
Dt, M
Copy from the source (Sc) to the destination(Dt)
With the use of MOV instruction the content of the source register is copied into the destination register without any changes.
Example− MOV K, L
MVI
Rd, data
M, data
Move immediate 8-bit
The 8-bit data is stored in the destination register or memory.
Example− MVI K, 55L
LDA
16-bit address
Load the accumulator
The contents that are in the memory location, specified by a 16-bit address in the operand, are copied to the accumulator.
Example− LDA 2034K
LDAX
B/D Reg. pair
Load the accumulator indirect
The contents of the designated register pair point to a memory location. This instruction copies the contents of that memory location into the accumulator.
Example− LDAX K
LXI
Reg. pair, 16-bit data
Load the register pair immediate
The instruction loads 16-bit data in the register pair designated in the register or the memory.
Example− LXI K, 3225L
LHLD
16-bit address
Load H and L registers direct
The instruction copies the contents of the memory location pointed out by the address into register L and copies the contents of the next memory location into register H.
Example− LHLD 3225K
STA
16-bit address
16-bit address
The contents of the accumulator are copied into the memory location specified by the operand.
This is a 3-byte instruction, the second byte indicates low-order address and the third byte indicates the high-order address.
Example− STA 325K
STAX
16-bit address
Store the accumulator indirect
The contents of the accumulator are copied into the memory location specified by the contents of the operand.
Example− STAX K
SHLD
16-bit address
Store H and L registers direct
The contents of register L are stored in the memory location specified by the 16-bit address in the operand and the contents of H register are stored into the next memory location by incrementing the operand.
This is a 3-byte instruction, the second byte specifies the low-order address and the third byte specifies the high-order address.
Example− SHLD 3225K
XCHG
None
Exchange H and L with D and E
The contents of register H are exchanged with the contents of register D, and the contents of register L are exchanged with the contents of register E.
Example− XCHG
SPHL
None
Copy H and L registers to the stack pointer
The instruction loads the contents of the H and L registers into the stack pointer register. The contents of the H register gives the high-order address and the contents of the L register provide the low-order address.
Example− SPHL
XTHL
None
Exchange H and L with top of stack
The contents of the L register are being exchanged with the stack location that are pointed out by the contents of the stack pointer register.
The contents of the H register are exchanged with the next stack location (SP+1).
Example− XTHL
PUSH
Reg. pair
Push the register pair onto the stack
The contents of the register pair designated in the operand are copied onto the stack in the following sequence.
The stack pointer register is decremented and the contents of the high order register (B, D, H, A) are copied into that location.
The stack pointer register is decremented again and the contents of the low-order register (C, E, L, flags) are copied to that location.
Example− PUSH K
POP
Reg. pair
Pop off stack to the register pair
The contents of the memory location pointed out by the stack pointer register are copied to the low-order register (C, E, L, status flags) of the operand.
The stack pointer is incremented by 1 and the contents of that memory location are copied to the high-order register (B, D, H, A) of the operand.
The stack pointer register is again incremented by 1.
Example− POPK
OUT
8-bit port address
Output the data from the accumulator to a port with 8bit address
The contents of the accumulator are copied into the I/O port specified by the operand.
Example− OUT K9L
IN
8-bit port address
Input data to accumulator from a port with 8-bit address
The contents of the input port designated in the operand are read and loaded into the accumulator.
Example− IN5KL

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