From 7a6cf86e4dd3094ed5aa41bf76d93c28c89e85e7 Mon Sep 17 00:00:00 2001 From: Danny Holman Date: Wed, 20 Jan 2021 21:31:23 -0600 Subject: i386: add serial port support Add support for serial communication in the i386 architecture. Signed-off-by: Danny Holman --- arch/i386/serial.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) create mode 100644 arch/i386/serial.c (limited to 'arch/i386/serial.c') diff --git a/arch/i386/serial.c b/arch/i386/serial.c new file mode 100644 index 0000000..b172e82 --- /dev/null +++ b/arch/i386/serial.c @@ -0,0 +1,40 @@ +#include +#include "pic.h" + +#define PORT 0x3f8 + +static int serial_init(void) { + outb(PORT + 1, 0x00); + outb(PORT + 3, 0x80); + outb(PORT + 0, 0x03); + outb(PORT + 1, 0x00); + outb(PORT + 3, 0x03); + outb(PORT + 2, 0xC7); + outb(PORT + 4, 0x0B); + outb(PORT + 4, 0x1E); + outb(PORT + 0, 0xAE); + + if (inb(PORT + 0) != 0xAE) + return -1; + + outb(PORT + 4, 0x0F); + return 0; +} + +int serial_recieved(void) { + return inb(PORT + 5) & 1; +} + +char read_serial(void) { + while (serial_recieved() == 0); + return inb(PORT); +} + +int is_transmit_empty(void) { + return inb(PORT + 5) & 0x20; +} + +void write_serial(char a) { + while (is_transmit_empty() == 0); + outb(PORT, a); +} -- cgit v1.2.3