d79
        
         jmp start


prompt: db 0D,0A,'Choose port (COM1=1, COM2=2, COM3=3, COM4=4): $'
outstr: db 0D,80 dup 32
        db 0D,0A,0D,0A,'Status COM  is: '
val:    db 4 dup 0,'H',0D,0A,0D,0A,'$'

text:   db 'Data Ready                      : N',0D,0A
        db 'Overrun Error                   : N',0D,0A
        db 'Parity Error                    : N',0D,0A
        db 'Framing Error                   : N',0D,0A
        db 'Break Detected                  : N',0D,0A
        db 'Empty transmit holding register : N',0D,0A
        db 'Empty transmit shift register   : N',0D,0A
        db 'Timeout                         : N',0D,0A

        db 80 dup 196  

        db 'Delta Clear To Send             : N',0D,0A
        db 'Delta Data Set Ready            : N',0D,0A 
        db 'Trailing edge ring detector     : N',0D,0A
        db 'Delta receive line signal detect: N',0D,0A
        db 'Clear To Send                   : N',0D,0A
        db 'Data Set Ready                  : N',0D,0A
        db 'Ring indicator                  : N',0D,0A
        db 'Received line signal detect     : N',0D,0A
        db 0D,0A
txtlen equ $-text


start:        
        mov ah,09H                      ;Write string to screen
        mov dx,prompt
        int 21H

        mov ah,00H
        int 16H
        and ax,0ff
        
        cmp al,031
        jge >l1
        jmp ending
l1:     cmp al,034  
        jle >l2
        jmp ending
l2:        
        mov dx,ax
        
        mov bp,outstr
        mov b[bp+95],dl
        
        sub dx,031
        mov ah,03H                      ;Get status COM4
        int 14H

        push ax

        mov bp,val        
        
        mov bl,ah                       ;Calculate ASCII values
        call calc
        mov bl,al
        call calc


        mov ah,09H                      ;Write string to screen
        mov dx,outstr
        int 21H

        pop ax
        push ax

        mov bp,text
        mov si,34
        mov dl,2
        mov al,1
        mov cx,8
        mov bl,ah

rslp:        
        test bl,al
        jz >l2
        mov b[bp+si],'Y'
l2:     mul dl  
        add si,37
        loop rslp
        

        add si,80
        pop ax
        mov bl,al
        mov al,1
        mov cx,8

modlp:        
        test bl,al
        jz >l2
        mov b[bp+si],'Y'
l2:     mul dl  
        add si,37
        loop modlp
        
        
        mov ah,40H                      ;Write text
        mov bx,01H                      ;Stdout
        mov cx,txtlen
        mov dx,text
        int 21H

        
        
        mov bp,text
        mov si,34
        mov cx,8

rsclr:        
        mov b[bp+si],'N'
        add si,37
        loop rsclr

        add si,80
        mov cx,8

modclr:        
        mov b[bp+si],'N'
        add si,37
        loop modclr
        
        
        jmp start




ending:
        mov ax,04c00                    ;That's it!
        int 21H

        
calc:        
        mov dl,bl        
        shr dl,4                        ;We want the left character
        and dl,0F
        add dl,030

        mov b[bp],dl
        inc bp

        mov dl,bl
        and dl,0F                       ;No shift here
        add dl,030

        mov b[bp],dl
        inc bp

        ret

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