52 lines
1.1 KiB
C
52 lines
1.1 KiB
C
#include <stdint.h>
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#include <stdbool.h>
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#include "io.h"
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#include "putchar.h"
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#define SERIAL_PORT 0x3f8
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static int serial_received(void) {
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return io_inb(SERIAL_PORT + 5) & 1;
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}
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static uint8_t serial_read(void) {
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while (serial_received() == 0);
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return io_inb(SERIAL_PORT);
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}
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static int serial_trans_empty(void) {
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return io_inb(SERIAL_PORT + 5) & 0x20;
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}
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static void serial_write(uint8_t value) {
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while (!serial_trans_empty());
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io_outb(SERIAL_PORT, value);
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}
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// REFERENCE: https://wiki.osdev.org/Serial_Ports
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bool serial_init(void) {
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io_outb(SERIAL_PORT + 1, 0x00);
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io_outb(SERIAL_PORT + 3, 0x80);
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io_outb(SERIAL_PORT + 0, 0x03);
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io_outb(SERIAL_PORT + 1, 0x00);
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io_outb(SERIAL_PORT + 3, 0x03);
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io_outb(SERIAL_PORT + 2, 0xc7);
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io_outb(SERIAL_PORT + 4, 0x0b);
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io_outb(SERIAL_PORT + 4, 0x1e);
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io_outb(SERIAL_PORT + 0, 0xae);
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if (io_inb(SERIAL_PORT + 0) != 0xae) {
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return false;
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}
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io_outb(SERIAL_PORT + 4, 0x0f);
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return true;
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}
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#if PUTCHAR_ == PUTCHAR_SERIAL
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// For printf library
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void putchar_(char c) {
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serial_write(c);
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}
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#endif
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