I did something similar back in the DOS era for a serial port library: https://github.com/kstenerud/DOS-Serial-Library/blob/master/serial.c https://github.com/k

I did something similar back in the DOS era for a serial port library: https://github.com/kstenerud/DOS-Serial-Library/blob/master/serial.c https://github.com/kstenerud/DOS-Serial-Library/blob/master/...