8085 Instruction Set


DATA TRANSFER INSTRUCTIONS

Copy from source to destination
MOV
Rd, Rs
This instruction copies the contents of the source register into the destination register, the contents of Rd, M the source register are not altered.  If one of the operands is a memory location, its location is specified by the contents of the HL registers.
Example:  MOV B, C   or  MOV B, M
M, Rs
Rd, M


Move immediate 8-bit
MVI
Rd, data
The 8-bit data is stored in the destination register or memory.  If the operand is a memory location, its location is specified by the contents of the HL registers.
Example:  MVI B, 57H  or  MVI M, 57H
M, data

Load accumulator
LDA
16-bit address
The contents of a memory location, specified by a 16-bit address in the operand, are copied to the accumulator. The contents of the source are not altered.
Example:  LDA 2034H

Load accumulator indirect
LDAX
B/D Reg. pair
The contents of the designated register pair point to a memory location.  This instruction copies the contents of that memory location into the accumulator.  The contents of either the register pair or the memory location are not altered.
Example:  LDAX B

Load register pair immediate
LXI
Reg. pair, 16-bit data
The instruction loads 16-bit data in the register pair designated in the operand. Example:  LXI H, 2034H  or  LXI H, XYZ

Load H and L registers direct
LHLD
16-bit address
The instruction copies the contents of the memory location pointed out by the 16-bit address into register L and copies the contents of the next memory location into register H.  The contents of source memory locations are not altered.
Example:  LHLD 2040H

Store accumulator direct
STA
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 specifies the low-order address and the third byte specifies the high-order address.
Example:  STA 4350H

Store accumulator Indirect
STAX
Reg. pair
The contents of the accumulator are copied into the memory location specified by the contents of the operand (register pair).  The contents of the accumulator are not altered.
Example:  STAX B

Store H and L registers direct
SHLD
16-bit address
The contents of register L are stored into 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.  The contents of registers HL are not altered.  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 2470H

Exchange H and L with D and E
XCHG
none
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

Copy H and L registers to the stack pointer
SPHL
none
The instruction loads the contents of the H and L registers into the stack pointer register, the contents of the H register provide the high-order address and the contents of the L register provide the low-order address.  The contents of the H and L registers are not altered.
Example:  SPHL

Exchange H and L with top of stack
XTHL
none
The contents of the L register are exchanged with the stack location 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); however, the contents of the stack pointer register are not altered.
Example:  XTHL

Push register pair onto stack
PUSH
Reg. pair
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 B or PUSH A

Pop off stack to register pair
POP
Reg. 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:  POP H or POP A

Output data from accumulator to a port with 8-bit address
OUT
8-bit port address
The contents of the accumulator are copied into the I/O port specified by the operand.
Example:  OUT F8H





Input data to accumulator from a port with 8-bit address
IN
8-bit port address
8-bit port address The contents of the input port designated in the operand are read and loaded into the accumulator.
 Example:  IN 8CH


1 comment:

  1. write a program to load two unsigned numbers in register B and C respectively, subtract C from B if the result is in 2's complement then convert the result in Absolut magnitude and location 3030H, else display the positive result? display it at location 3030h, else display the positive result.

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