39 lines
786 B
C
39 lines
786 B
C
#include <stddef.h>
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#include "serial.h"
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#include "io.h"
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static void set_baud_rate(void)
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{
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u8 line_control_register = inb(COM1 + 3);
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outb(COM1 + 3, DLAB | line_control_register);
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outb(COM1, 3);
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outb(COM1 + 1, 0);
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outb(COM1 + 3, line_control_register);
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}
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void init_serial(void)
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{
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set_baud_rate();
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outb(COM1 + 3, NO_PARITY | EIGHT_BITS_LENGTH);
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outb(COM1 + 2, FIFO | TRIGGER_LVL_14 | CLEAR_TRANSMIT_FIFO
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| CLEAR_RECEIVE_FIFO);
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outb(COM1 + 1, ENABLE_TRANSMITTER);
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}
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int write(const char *buf, size_t count)
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{
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size_t sent;
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for(sent = 0; sent < count; ++sent)
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{
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u8 line_status = inb(COM1 + 5);
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if (!(line_status & EMPTY_TRANSMITTER))
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break;
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outb(COM1, buf[sent]);
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}
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return sent;
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}
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