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;set video mode, define es            mov ax,13h            int 10h                        mov ax,0a000h            mov es,ax            xor di, di            mov ax, 0c0ch    ;bright red as starting colour            ;draw first linefirst_line: mov cx, 160            rep stosw       ;draw with bright red;draw sides                        mov cx, 198      ;for the next 198 linessides:      mov byte [es:di], 0ch           ;draw left side            add di, 319      ;jump to right side            mov byte [es:di], 0ch           ;draw right side            inc di            dec cx            jnz sides;draw last line            last_line:  mov cx,160            rep stosw       ;draw with bright red            kb:         mov ah,08h            int 21h            cmp al,71h      ;exit with q, otherwise loop            jne kb            mov ax, 3h            int 10h            mov ah, 4ch            int 21h