ei502 microprocessors & micrtocontrollers part 2(instructionset)
DESCRIPTION
Instruction set and some assembly programmingTRANSCRIPT
Mallabhum Institute of Technology Debasis Das 1
EI 502Microprocessors
& Microcontrollers
Part 2(Instruction Set)
Debasis Das
Aug 2011
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Addressing Modes
Immediate addressing
Register addressing
Direct Addressing
Indirect addressing
Implicit addressing
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General Instruction Format
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Opcode
Operand 1 Operand 2
Note: 1. Instruction may include 0, 1 or 2 operands
SourceDestination
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Immediate AddressingValue following the instruction op code is the operand
MVI D, FF hexadecimal FF value will be loaded into register D
LXI H, 1234 hexadecimal 1234, a 16 bit value will be loaded
into H-L register pair
ADI 44 hex 44 will be added to the value in the accumulator
CPI 55 hex 55 will be compared to the value in accumulator
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Register AddressingOperand values stored in specified registers are
usedMOV A, B operand contained in register B is moved
to register A, the accumulatorADD C operand value stored in register C is added
to accumulatorSUB B operand stored in B is subtracted from the
value in APCHL Exchange values contained in HL and PC
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Direct AddressingValue of the operand is a direct memory or I/O
address
LDA ABC5 the operand is a memory address from
which the value is to be loaded into the accumulator
STA 123F value in accumulator to be stored into
memory location 123F
IN 23 input data from I/O port 23 hexAug 2011
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Indirect Addressing(Register Indirect)
Value of the operand is a pointer to memory location containing data
MOV M,B moves content of register B to memory location pointed to by the register pair H-L
ADD M add content of memory pointed to by H-LMOV A,M move memory content pointed by H-L to
accumulatorLDAX B load accumulator with value contained in
memory location pointed by B-C
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Implicit AddressingThe operand is known and thus not needed in the
instruction
STC set carry flag
RAL rotate accumulator left
DAA decimal; adjust accumulator
CMA complement accumulatorAug 2011
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8085/8085A Instruction SetData Transfer Instructions
Arithmetic instructions
Logical instructions
Branch instructions
Stack operations, I/O and Machine control
operations
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Data Transfer Instructions
MOV r1, r2MOV r, MMOV M, rMVI, r, dataMVI M, dataLXI rp, dataLDA addr
STA addrLHLD addrSHLD addrLDAX rpSTAX rpXCHG
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Arithmetic Instructions
ADD rADD MADI dataADC rADC MACI dataSUB rSUB MSUI dataSBB r
SBB MSRI dataINR rINR MDCR rDCR MINX rpDCX rpDAD rpDAA
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Logical InstructionsANA rANA MANI dataXRA rXRA MXRI dataORA rORA MORI dataCMP r
CMP MCPI dataRLCRRCRALRARCMACMCSTC
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Branch InstructionsJMP addr
Jcondition addr
CALL addr
Ccondition addr
RET
Rcondition
PCHL
ConditionsCarryNo carryPositiveMinusZeroNon zeroParity evenParity odd
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Stack, I/O, Machine ControlInstructions
PUSH rpPOP rpPUSH PSWPOP PSWXTHLSPHLIN port no.
OUT port no.EIDINOPHLTRIMSIM
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1,2,3 Byte Instruction Structures
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Op code
Op code
Data/address
Op code
Least Significant Byte
Most Significant Byte
One byte instructions
Two byte instructions
Three byte instructions
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Typical Program Structure
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1000
1003
1006
1008
100B
100C
100D
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Add N 8bit Numbers
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Sort in Descending Order
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Find Largest Number
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Multiplying Two numbers
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Division of Two Numbers
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