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littleosbook / littleosbook

Source for the little book about OS development
http://littleosbook.github.io/
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4.3.2 Configuring the Line: high byte should go in base + 1 port #38

Open andrewnguyen opened 9 years ago

andrewnguyen commented 9 years ago

4.3.2 has the code listing: 

void serial_configure_baud_rate(unsigned short com, unsigned short divisor)
{
    outb(SERIAL_LINE_COMMAND_PORT(com),
         SERIAL_LINE_ENABLE_DLAB);
    outb(SERIAL_DATA_PORT(com),
         (divisor >> 8) & 0x00FF);
    outb(SERIAL_DATA_PORT(com),
         divisor & 0x00FF);
}

but according to http://wiki.osdev.org/Serial_ports the high byte should go into the base+1 port.

um0699 commented 7 years ago

I believe you are correct: UART registers Check Divisor Latch Low Byte and Divisor Latch High Byte.