The following addressing modes are supported for the ADD instruction.
1. Immediate:            ADD A, #data

                                Example: ADD A,#40H

2. Register:               ADD A, Rn

                                Example: ADD A,R1

3. Direct:                  ADD A, direct

                                Example: ADD A, 20H              ;Add data in RAM location 20H to A

4. Register-indirect:    ADD A,@Ri

                                Example: ADD A,@R0             ;Add to A data pointed by R0  

ADDC A,  source byte

Function : Add with carry

Flags : OV, AC, CY

Description: ADDC simultaneously adds the byte variable indicated, the carry flag and the accumulator contents, leaving the result in the accumulator. The carry and auxiliary carry flags are set, respectively, if there is a carry out of bit 7 or bit 3, and cleared otherwise. When adding unsigned integers, the carry flag indicates an overflow occurred.

OV is set if there is a carry out of bit 6 but not out of bit 7, or a carry out of bit 7 but not out of bit 6; otherwise OV is cleared. When adding signed integers, OV indicates a negative number produced as the sum of two positive operands or a positive sum from two negative operands.

Four source operand addressing modes are allowed: register, direct, register indirect, or immediate.

Example:       mov a, #0C3H                  ; (A) ← 0C3H
                    mov R0,#0AAH                ; (R0) ← 0AAH  assume (CY) = 1
                    ADDC A, R0

Result :         (A) = 6EH with (AC) = 0, (CY) = 1, (OV) = 1.                     

The addressing modes for ADDC are same as for ADD A,byte.

AJMP target address

Function : Absolute jump

Flags : None

Description: AJMP transfers program execution to the indicated address, which is formed at runtime by concatenating the high-order five bits of the PC (after incrementing the PC twice), op code bits 7-5, and the second byte of the instruction. The destination must therefore be within the same 2K block of program memory as the first byte of the instruction following AJMP.

Example: The label ”JMPADR” is at program memory location 0123H. The instruction AJMP JMPADR is at location 0345H and will load the PC with 0123H.

ANL dest-byte, src-byte

Function : Logical AND for byte variables

Flags : None

Description: ANL performs the bitwise logical AND operation between the variables indicated and stores the results in the destination variable. No flags are affected. The two operands allow six addressing mode combinations. When the destination is a accumulator, the source can use register, direct, register-indirect, or immediate addressing; when the destination is a direct address, the source can be the accumulator or immediate data.

Note: When this instruction is used to modify an output port, the value used as the original port data will be read from the output data latch, not the input pins.

Example: If the accumulator holds 0C3H (11000011B) and register 0 holds 0AAH(10101010B) then the instruction ANL A,R0 will leave 81H (10000001B) in the accumulator.

For an ANL instruction there are a total of six addressing modes.

1. Immediate:         ANL A, #data

                             Eample : ANL A,#30h

2. Register:             ANL A, Rn

                             Example : ANL A, R5

3. Direct:               ANL A,direct

                             Example : ANL A,20H     ; AND A with data in RAM location 20H

4. Register-indirect: ANL A, @Ri

                             Example : ANL A,@R1   ; AND A with data pointed by R0

            In the next two addressing modes the destination is direct address while the source is either A or immediate data.

5. ANL direct,A

    Example : ANL 20H, A

6. ANL direct, #data

    Example : ANL 40H, #30H

ANL C, src-bit

Function : Logical AND for bit variables

Flags : CY

Description: In this instruction the carry flag bit is ANDed with a source bit and the result is placed in carry. If the Boolean value of the source bit is a logic 0 then clear the carry flag; otherwise leave the carry flag in its current state. Only direct bit addressing is allowed for the source operand. A slash (”/”) preceding the operand in the assembly language indicates that the logical complement of the addressed bit is used as the source value, but the source bit itself is not affected.

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