16 bit programs of 8085, addition, subtraction, multiplication and division of two 16 bit number.

  Adiition of two 16 bit numbers:-

some important instructions which are used to 16 bit prgrams :-

1. LHLD :- load H-L register direct

•  This instruction copies the contents of memory location pointed out by 16-bit address into register L.
• It copies the contents of next memory location into

  register H.
• Example: LHLD 2040 H

2.SHLD:-Store H-L registers direct.

• The contents of register L are stored into memory location 

           specified by the 16-bit address.

• The contents of register H are stored into the next memory location..
• Example: SHLD 2550 H

3. XCHG :- Exchange H-L with D-E.

• The contents of register H are exchanged with the
  contents of register D.
• The contents of register L are exchanged with the

  contents of register E.

4. DAD:- Add register pair to H-L pair.

• The 16-bit contents of the register pair are added to the

  contents of H-L pair.
• The result is stored in H-L pair.
• If the result is larger than 16 bits, then CY is set.
• No other flags are changed.

5. ADC:- Add register or memory to accumulator with

carry.

• The contents of register or memory and Carry Flag (CY) are added to

  the contents of accumulator.
• The result is stored in accumulator.
• If the operand is memory location, its address is specified by H-L pair.
• All flags are modified to reflect the result of the addition.

• Example: ADC B or ADC M

6. SBB:- Subtract register or memory from accumulator

with borrow.

• The contents of the register or memory location and Borrow Flag (i.e.

  CY) are subtracted from the contents of the accumulator.
• The result is stored in accumulator.
• If the operand is memory location, its address is specified by H-L
• All flags are modified to reflect the result of subtraction.

• Example: SBB B or SBB M

PROGRAM:-

           LDA 0000 H

          MOV B, A

          LDA 0002 H

         ADD B

         STA 0004 H

         LDA 0001 H

         MOV B, A

         LDA 0003 H

        ADC B          ( A+B+CY)

        STA  0005 H

         HLT

2nd method:-

LHLD 0000 H

XCHG                (HL to DE)

LHLD 0002H

DAD D    (H+D & D+E)

SHLD

HLT

subtraction of two 16 bit number :-

LDA 0002 H   (load 8 bit data)

MOV B, A       ( move accumulator to register B)

LDA 0000 H

SUB B              ( SUB A-B= A)

STA 0004 H      (result store in location)

LDA 0003 H

MOV B, A

LDA 0001 H

SBB B               (subtract with borrow)

STA 0005 H      (store carry)

HLT