Unit 2 8085 microprocessor instruction set 2 1

Unit 2 8085 microprocessor instruction set

2. 1 • Instruction : instruction is a command for microprocessor to perform a particular task. • Opcode : which specify the operation to be perform. • Operand: data to be operated on is called operand.

(2. 2) Instruction • Classification of instruction 1)data transfer group 2)arithmatic group 3)logical group 4)branch group 5) stack , I/O and machine control group

Data transfer group • • • MVI r, data (8 - Bit) MVI M, data (8 - Bit) MOV rd, rs MOV M, rs MOV rd, M LXI rp, data (16 bit)

• • STA addr LDA addr SHLD addr LHLD addr STAX addr LDAX rp XCHG

EXAMPLE • • • MOV Rd, Rs MVI R, 8 bit LXI Rp, 16 bit MOV R, M MOV M, R LDA 16 bit STA 16 bit LDAx Rp STAX Rp MOV B, C MVI A, 05 H LXI B, 2050 MOV D, M MOV M, E LDA 8005 H STA 8006 H LDAx B STAX D

ARITHMATIC GROUP • • ADD r ADD M ADI data (8) ADC r ADC M ACI data (8) DAD rp

• • SUB r SUB M SUI data SBB r SBB M SBI data DAA

• • • INR r INR M INX rp DCR r DCR M DCX rp

• • • ADD R ADI 8 bit SUB R SUI 8 bit INR R DCR R INR M DCR M INX Rp DCX Rp EXAMPLE ADD B ADI 59 H SUB C SUI 37 H INR D DCR B INR M DCRB M INX B

LOGICAL GROUP • • ANA r ANA M ANI data XRA r XRA M XRI data ORA r ORA M

• • ORI data CMP r CMP M CPI data STC CMA

Example • • • ANA R/M ANI 8 bit ORA R/M ORI 8 bit XRA R/M XRI 8 bit RLC RAL RRC RAR CMP R/M ANA D ORA C XRA D

BRANCH GROUP • JUMP INSTRUCTION • CALL and RETURN INSTRUCTION • RESTART INSTRUCTION

JUMP INSTRUCTION • • • JMP 16 bit Address JZ 16 bit Address JNZ 16 bit Address JC 16 bit Address JNC 16 bit Address • HLT • NOP Stop processing and wait Don’t perform anything - delay

STACK OPERATION I/O & CONTROL GROUP • PUSH • POP • RESTART RST n