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📘 Intel 8085 Instruction Set Reference

🧠 Table of Contents

## 🚚 Data Transfer Instructions

### 1. MOV — Move Data Between Registers/Memory

Syntax:

MOV destination, source

Description: Copies the contents of the source register/memory to the destination register/memory.

Example Description
MOV A, B Copy contents of B to A
MOV M, A Store A into memory at (HL)

2. MVI — Move Immediate Data

Syntax:

MVI register, data8
MVI M, data8

Description: Loads an 8-bit immediate value into a register or memory.

Example Description
MVI A, #1F Load 1F (hex) into A
MVI M, #05 Store 05 (hex) at memory (HL)

3. LXI — Load Register Pair Immediate

Syntax:

LXI rp, data16

Description: Loads a 16-bit immediate value into a register pair (B, D, H, or SP).

Example Description
LXI H, #9000 HL = 9000H
LXI SP, #FF00 SP = FF00H

4. LDA/STA — Load/Store Accumulator Direct

Syntax:

LDA address16
STA address16

Description:

  • LDA: Loads accumulator from memory address.
  • STA: Stores accumulator to memory address.
Example Description
LDA #9000 A = [9000H]
STA #9002 [9002H] = A

5. LHLD/SHLD — Load/Store HL Pair Direct

Syntax:

LHLD address16
SHLD address16

Description:

  • LHLD: Loads HL pair from two consecutive memory locations.
  • SHLD: Stores HL pair to two consecutive memory locations.
Example Description
LHLD #9000 HL = [9000H] + [9001H]
SHLD #9100 [9100H] = L, [9101H] = H

## ➕ Arithmetic Instructions

1. ADD/ADI — Add Register/Immediate to Accumulator

Syntax:

ADD source
ADI data8

Description: Adds the source register/memory or immediate value to the accumulator (A).

Example Description
ADD B A = A + B
ADD M A = A + [HL]
ADI #10 A = A + 10H

2. ADC — Add with Carry

Syntax:

ADC source

Description: Adds source and carry flag to accumulator.

Example Description
ADC C A = A + C + CY

3. SUB/SUI — Subtract Register/Immediate from Accumulator

Syntax:

SUB source
SUI data8

Description: Subtracts source register/memory or immediate value from accumulator.

Example Description
SUB D A = A - D
SUI #05 A = A - 05H

4. SBB — Subtract with Borrow

Syntax:

SBB source

Description: Subtracts source and borrow (carry flag) from accumulator.

Example Description
SBB E A = A - E - CY

5. INR/DCR — Increment/Decrement Register/Memory

Syntax:

INR destination
DCR destination

Description: Increments or decrements the specified register or memory by 1.

Example Description
INR B B = B + 1
DCR M [HL] = [HL] - 1

## 🧩 Logical Instructions

1. ANA — Logical AND with Accumulator

Syntax:

ANA source

Description: Logical AND between accumulator and source.

Example Description
ANA H A = A & H

2. ORA — Logical OR with Accumulator

Syntax:

ORA source

Description: Logical OR between accumulator and source.

Example Description
ORA L A = A

3. XRA — Logical XOR with Accumulator

Syntax:

XRA source

Description: Logical XOR between accumulator and source.

Example Description
XRA M A = A ^ [HL]

4. CMA — Complement Accumulator

Syntax:

CMA

Description: Complements (bitwise NOT) the accumulator.

Example Description
CMA A = ~A

5. CMP/CPI — Compare Register/Immediate with Accumulator

Syntax:

CMP source
CPI data8

Description: Compares source or immediate with accumulator (sets flags, does not change A).

Example Description
CMP B Compare B with A
CPI #20 Compare 20H with A

## 🔀 Branch Instructions

1. JMP — Unconditional Jump

Syntax:

JMP address16

Description: Sets PC to address.

Example Description
JMP #8000 Jump to address 8000H

2. JZ/JNZ/JC/JNC — Conditional Jumps

Syntax:

JZ address16   ; Jump if Zero flag set
JNZ address16  ; Jump if Zero flag not set
JC address16   ; Jump if Carry flag set
JNC address16  ; Jump if Carry flag not set

Description: Jumps to address if condition is met.

Example Description
JZ #8010 Jump to 8010H if Zero flag is set
JNC #8020 Jump to 8020H if Carry not set

3. CALL/RET — Subroutine Call/Return

Syntax:

CALL address16
RET

Description:

  • CALL: Pushes PC to stack, jumps to address.
  • RET: Pops address from stack to PC.
Example Description
CALL #9000 Call subroutine at 9000H
RET Return from subroutine

## 📚 Stack Operations

1. PUSH/POP — Stack Operations

Syntax:

PUSH rp
POP rp

Description:

  • PUSH: Pushes register pair onto stack.
  • POP: Pops two bytes from stack into register pair.
Example Description
PUSH B Push BC onto stack
POP H Pop two bytes into HL

## 🕹️ Control Instructions

1. HLT — Halt

Syntax:

HLT

Description: Halts program execution.

Example Description
HLT Stop execution

2. NOP — No Operation

Syntax:

NOP

Description: Does nothing (1 machine cycle).

Example Description
NOP No operation

## 🛠️ Special Instructions

1. DAA — Decimal Adjust Accumulator

Syntax:

DAA

Description: Adjusts A for BCD addition.

2. STC/CMC — Set/Complement Carry

Syntax:

STC
CMC

Description:

  • STC: Sets carry flag.
  • CMC: Complements carry flag.

3. EI/DI — Enable/Disable Interrupts

Syntax:

EI
DI

Description:

  • EI: Enable interrupts.
  • DI: Disable interrupts.

4. RIM/SIM — Read/Set Interrupt Mask

Syntax:

RIM
SIM

Description:

  • RIM: Read interrupt mask.
  • SIM: Set interrupt mask.

5. Rotate Instructions

Syntax:

RLC   ; Rotate accumulator left
RRC   ; Rotate accumulator right
RAL   ; Rotate accumulator left through carry
RAR   ; Rotate accumulator right through carry

Description: Rotates bits in accumulator (A) as described.

📝 Usage Example: Addition of Two Numbers

MVI A, #05      ; Load 05H into A
MVI B, #03      ; Load 03H into B
ADD B           ; A = A + B (A = 08H)
STA #9000       ; Store result at 9000H
HLT             ; Halt

🏁 End of Instruction Reference