Archive for May 2012

XCHG, SPHL, XHTL, PUSH, POP, OUT, IN

10. XCHG: - 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.

Eg: - XCHG



11. SPHL: - This instruction copies H and L register to the stack pointer. The instruction loads

MOV, MVI, LDA, LDAX, LXI, LHLD, STA, STAX,SHLD

1.MOV: - This instruction is used to copy the data from one place to another.

Eg: - MOV Rd, Rs (This instruction copies the content of Rs to Rd)
         MOV M,Rs (This instruction copies the content of register Rs to memory location pointed by HL Register)
         MOV Rd, M (This instruction copies the content of memory location pointed by the HL

NOP, HLT, DI, EI, RIM, SIM

1.NOP(No operation): - No operation is performed. The instruction is fetched and decoded. However no operation is executed.
Eg: - NOP


2. HLT(Halt): - The CPU finishes executing the current instruction and halts any further

PCHL, RST

1. PCHL: - Load program counter with HL contents. The contents of registers H and L are copied into the program counter. The contents of H are placed as the high-order byte and the contents of L as the low order byte.


2. RST: - The RST instruction is equivalent to a 1- byte call instruction to one of eight memory

Return Instruction, RC, RNC, RP, RM, RZ, RNZ,RPE, RPO, RET

The program sequence is transferred from the subroutine to the calling program based on the specified flag of the PSW as described below. The two bytes from the top of the stack are copied into the program counter, and program execution begins at the new address.
1. RC: - (conditional call)  The program sequence is transferred to a particular level or a 16-bit address if C=1 (or carry is 1)
  
Eg: - RC ABC (jump to the level abc if C=1)
2. RNC: - (conditional call)  The program sequence is transferred to a particular level or a 16-bit

Call Instruction, CC, CNC, CP, CM, CZ, CNZ, CPE, CPO

1. CC: - (conditional call)  The program sequence is transferred to a particular level or a 16-bit address if C=1 (or carry is 1)
  
Eg: - CC ABC (jump to the level abc if C=1)
2. CNC: - (conditional call)  The program sequence is transferred to a particular level or a 16-bit address if C=0 (or carry is 0)
  
Eg: - CNC ABC (jump to the level abc if C=0)
3. CP: - (conditional call)  The program sequence is transferred to a particular level or a 16-bit

Jump Instruction, JMP, JC, JNC, JP, JM, JZ, JNZ, JPE, JPO

1. JMP: -  (unconditionally jump) The program sequence is transferred to the memory location specified by the16-bit address given in the operand.
Eg: - JMP 2034H ( jump to location 2034H) there is no condition to jump.
         JMP ABC (jump to abc level)



2. JC: - (conditional jump)  The program sequence is transferred to a particular level or a 16-bit address if C=1 (or carry is 1)
  


INR, INX, DCR, DCX, DAA instruction

11. INR: - The contents of the designated register or memory) are incremented by 1 and the result is stored in the same place. If the operand is a memory location, its location is specified by the contents of the HL registers.

Eg: -INR B( the content of register B is incremented by 1.
       INR M( the content of memory location pointed by HL pair in incremented by 1)


12. INX: - Increment register pair by 1.

Eg: INX H (It means the location pointed by the HL pair is incremented by 1)



13.DCR: - The contents of the designated register or memory are M decremented by 1 and the

SUB, SBB, SUI, SBI, instruction

7. SUB: -  substract the content of a register or a memory location form the content of accumulator and the result is stored in the accumulator.


Eg: - SUB B( it substracts the content of B register from the content of the accumulator.


         SUB M( it substracts the content of memory location pointed by HL pair from the content of


        

LXI, DAD, instruction

5. LXI: Load register Pair immediate

Eg:- LXI H, 2030H (This instruction loads the memory address in HL register, here it works as memory pointer)


6. DAD: -  Add register pair to HL register. The 16-bit contents of the specified register pair are

Arithmetic Instruction In 8085, ADD, ADC, ADI, ACI

There are some of the important instructions in 8085 microprocessor.

1. ADD: - The content of operand are added to the content of the accumulator and the result is stored in Accumulator.

Eg- ADD B  (it adds the content of accumulator to the content of the register B)
     
      ADD M (if content is stored in memory location the it is added with the content stored in accumulator)


2. ADC: -

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