e7c
CSEG    SEGMENT
        ASSUME CS:CSEG,DS:CSEG
        ORG 100h

Start:  jmp begin


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

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

        db 80 dup (196)  

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


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

        mov ah,00H
        int 16H
        and ax,0ffh
        
        cmp al,31h
        jge lb1
        jmp ending
lb1:    cmp al,34h  
        jle lb2
        jmp ending
lb2:        
        mov dx,ax
        
        mov bp,offset outstr
        mov byte ptr[bp+95],dl
        
        sub dx,31h
        mov ah,03H                      ;Get status COM4
        int 14H

        push ax

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


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

        pop ax
        push ax

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

rslp:        
        test bl,al
        jz lb3
        mov byte ptr[bp+si],'Y'
lb3:    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 lb4
        mov byte ptr[bp+si],'Y'
lb4:    mul dl  
        add si,37
        loop modlp
        
        
        mov ah,40H                      ;Write text
        mov bx,01H                      ;Stdout
        mov cx,txtlen
        mov dx,offset text
        int 21H

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

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

        add si,80
        mov cx,8

modclr:        
        mov byte ptr[bp+si],'N'
        add si,37
        loop modclr
        
        
        jmp begin




ending:
        mov ax,4c00h                    ;That's it!
        int 21H

        
calc:        
        mov dl,bl        
        mov cl,4
        shr dl,cl                        ;We want the left character
        and dl,0Fh
        add dl,30h

        mov byte ptr[bp],dl
        inc bp

        mov dl,bl
        and dl,0Fh                       ;No shift here
        add dl,30h

        mov byte ptr[bp],dl
        inc bp

        ret

CSEG    ENDS
END     Start
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