From 59f86fe8dd237e50c7fea03b506125e3abff0157 Mon Sep 17 00:00:00 2001 From: Aleksa Vuckovic Date: Mon, 5 Sep 2022 04:19:56 +0200 Subject: serial output --- kernel/src/devices/serial.c | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 kernel/src/devices/serial.c (limited to 'kernel/src/devices') diff --git a/kernel/src/devices/serial.c b/kernel/src/devices/serial.c new file mode 100644 index 0000000..76bc71a --- /dev/null +++ b/kernel/src/devices/serial.c @@ -0,0 +1,37 @@ +#include +#include + +void init_serial() +{ + outb(PORT + 1, 0x00); // Disable all interrupts + outb(PORT + 3, 0x80); // Enable DLAB (set baud rate divisor) + outb(PORT + 0, 0x03); // Set divisor to 3 (lo byte) 38400 baud + outb(PORT + 1, 0x00); // (hi byte) + outb(PORT + 3, 0x03); // 8 bits, no parity, one stop bit + outb(PORT + 2, 0xC7); // Enable FIFO, clear them, with 14-byte threshold + outb(PORT + 4, 0x0B); // IRQs enabled, RTS/DSR set +} + +uint8_t serial_received() +{ + return inb(PORT + 5) & 1; +} + +char read_serial() +{ + while (serial_received() == 0); + + return (char)inb(PORT); +} + +uint8_t is_transmit_empty() +{ + return inb(PORT + 5) & 0x20; +} + +void write_serial(char c) +{ + while (is_transmit_empty() == 0); + + outb(PORT, (uint8_t)c); +} -- cgit v1.2.3