Binary to Decimal

%OUT-----------------------------------------------------------------------------------------

%OUT- Prints a 8-bit binary number in its equivalent decimal form                               

%out- input: 8-bit binary string accepted from the user                                                  

%out- output: 3 digit decimal equivalent of the binary string is printed 

%out – author: Ayon and Ariyam                                            

%OUT-----------------------------------------------------------------------------------------

if1

include macrolib.lby

endif

.model small

.stack

.data

count equ 08h                                                                                ;for 8-bit binary string

ip db "Enter a 8-bit binary number: ","$"                                             

;a request to prompt the user for entering the binary no.

op db "  Decimal form:  ","$"                                                        ;output message

err db " Invalid Entry!","$"                                                             ;error message

heading db "***** BINARY to DECIMAL *****","$"                   ;a heading

.code

           

main proc

            clrscrn                                                            ;clearing the screen

            mov dx,0105h

            cursor                                                             ;setting up the cursor

            showmsg heading                                     ;displaying heading

           

            mov dx,0303h                                             ;pointing to next line

            cursor                                                             ;setting up the cursor

            showmsg ip                                                  ;prompt the user to enter the binary string

                       

            xor bh,bh                                                      ;clearing register Bh

            mov cx,count                                             ;loading cx with length of the binary string

           

continue:      rol bh,01h                                        

;rotate BH left, 0 will come in the LSB of BH, as intially BH was cleared

                                    mov ah,01h

                                    int 21h

                                    sub al,30h                             ;getting the binary digit (bit 0 or 1) in AL

                                    cmp al,01h                           ;when bit is greater than 0 or 1

                                    ja WRONG

                                    add bh,al                             ;add the input bit (0 or 1) to BH

                                    loop continue                     ;iterate till 8 bits are accepted from the user

           

            ; Hexadecimal no. is stored in BH, LSD of its decimal equivalent is in BH

            ; Remaining part is stored in CH in hexadecimal form

            xor ch,ch                                                                  ;clearing reg. CH

            do1:                cmp bh,0ah

                                    jb complete1

                                    sub bh,0ah

                                    inc ch

                                    jmp do1

                       

            complete1:  mov cl,bh     ;LSD of decimal equivalent is now stored in CL

                                    mov bh,ch   ;dealing with remaining hexadecimal part same way

                                    xor ch,ch      ;clearing reg. CH

                                    do2:    cmp bh,0ah            ;middle digit is stored in BH & MSD in CH

                                                jb complete2

                                                sub bh,0ah

                                                inc ch

                                                jmp do2

                       

            complete2:  rol ch,1

                                    rol ch,1

                                    rol ch,1

                                    rol ch,1

                                    or bh,ch

           

            showmsg op            ;display output message, content of BH not hampered

            output                      ;calling output macro to display first 2 digits of the decimal number

           

            mov dl,cl                               ;displaying last decimal digit

            add dl,30h                           ;converting to ASCII value

            mov ah,02h

            int 21h

           

            jmp FINISH

           

WRONG:       showmsg err                        ;displaying error message           

FINISH:                       exit

           

main endp

end main