2 ; writechr: Write a single character in AL to the console without
3 ; mangling any registers; handle video pages correctly.
8 call write_serial ; write to serial port if needed
10 test byte [cs:UsingVGA], 08h
14 test byte [cs:DisplayCon], 01h
18 mov bl,07h ; attribute
19 mov bh,[cs:BIOS_page] ; current page