8051 Assembly Address Based 8 bit Subtraction with carry program

                ORG 0000H

                CLR C

                MOV R2, #00H

                MOV DPTR, #0030H

                MOVX A, @DPTR

                MOV R0, A

                INC DPTR

                MOVX A, @DPTR

                CPL A

    ADD A, #01H

    ADD A, R0

    MOV R6, A

    JNC OVER1

    INC R2

    MOV DPTR, #0090H

                MOVX @DPTR, A

                MOV A, R6

                INC DPTR

                MOVX @DPTR, A

OVER1:   MOV DPTR, #0090H

                MOV A, R6

                CPL A

                ADD A, #01H

                MOVX @DPTR, A

                INC DPTR

                MOV A, R2

                MOVX @DPTR, A

                MOV PCON, #02H

Or

                ORG 0000H

                CLR C

                MOV R1, #00H

                MOV DPTR, #0030H

                MOVX A, @DPTR

                MOV R0, A

                INC DPTR

                MOVX A, @DPTR

                SUBB A, R0

                JNC OVER1

                INC R1

    MOV DPTR, #0090H

                MOVX @DPTR, A

                MOV A, R1

                INC DPTR

                MOVX @DPTR, A

OVER1:   MOV DPTR, #0090H

                MOVX @DPTR, A

                INC DPTR

                MOV A, R1

                MOVX @DPTR, A

                MOV PCON, #02H