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https://github.com/encounter/osdev.git
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Luke Street
33 lines
1.0 KiB
C
33 lines
1.0 KiB
C
#include "serial.h"
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#include "ports.h"
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#define COM1_BASE 0x3f8
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void serial_init() {
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port_byte_out(COM1_BASE + 1, 0x00); // Disable all interrupts
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port_byte_out(COM1_BASE + 3, 0x80); // Enable DLAB (set baud rate divisor)
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port_byte_out(COM1_BASE + 0, 0x03); // Set divisor to 3 (lo byte) 38400 baud
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port_byte_out(COM1_BASE + 1, 0x00); // (hi byte)
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port_byte_out(COM1_BASE + 3, 0x03); // 8 bits, no parity, one stop bit
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port_byte_out(COM1_BASE + 2, 0xC7); // Enable FIFO, clear them, with 14-byte threshold
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port_byte_out(COM1_BASE + 4, 0x0B); // IRQs enabled, RTS/DSR set
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}
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bool serial_received() {
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return (port_byte_in(COM1_BASE + 5) & 1) != 0;
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}
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char serial_read() {
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while (serial_received() == 0);
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return port_byte_in(COM1_BASE);
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}
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bool serial_transmit_empty() {
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return (port_byte_in(COM1_BASE + 5) & 0x20) != 0;
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}
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void serial_write(char a) {
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if (a == '\n') serial_write('\r');
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while (serial_transmit_empty() == 0);
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port_byte_out(COM1_BASE, (unsigned char) a);
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} |