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/*
RCC-Project
Copyright (C) 2026 Richard Qin
This file is part of RCC-Project.
RCC-Project is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3 of the License, or (at your option) any
later version.
RCC-Project is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
RCC-Project; see the file COPYING. If not see
<http://www.gnu.org/licenses/>.
*/
#include "bios.h"
#include "io.h"
#define COM1_BASE 0x03F8u
#define COM_DATA_OFFSET 0x00u
#define COM_IER_OFFSET 0x01u
#define COM_FCR_OFFSET 0x02u
#define COM_LCR_OFFSET 0x03u
#define COM_MCR_OFFSET 0x04u
#define COM_LSR_OFFSET 0x05u
#define COM_LCR_DLAB 0x80u
#define COM_LCR_8N1 0x03u
#define COM_FCR_ENABLE_FIFO 0x01u
#define COM_FCR_CLEAR_RX 0x02u
#define COM_FCR_CLEAR_TX 0x04u
#define COM_FCR_TRIGGER_14 0xC0u
#define COM_MCR_DTR 0x01u
#define COM_MCR_RTS 0x02u
#define COM_MCR_OUT2 0x08u
#define COM_LSR_THRE 0x20u
static u16
com1_port (u16 offset)
{
return (u16)(COM1_BASE + offset);
}
void
serial_init (void)
{
// clang-format off
io_out8(com1_port(COM_IER_OFFSET), 0x00u);
io_out8(com1_port(COM_LCR_OFFSET), COM_LCR_DLAB);
io_out8(com1_port(COM_DATA_OFFSET), 0x01u);
io_out8(com1_port(COM_IER_OFFSET), 0x00u);
io_out8(com1_port(COM_LCR_OFFSET), COM_LCR_8N1);
io_out8(
com1_port(COM_FCR_OFFSET),
COM_FCR_ENABLE_FIFO |
COM_FCR_CLEAR_RX |
COM_FCR_CLEAR_TX |
COM_FCR_TRIGGER_14
);
io_out8(
com1_port(COM_MCR_OFFSET),
COM_MCR_DTR |
COM_MCR_RTS |
COM_MCR_OUT2
);
// clang-format on
}
void
serial_putc (u8 value)
{
while ((io_in8 (com1_port (COM_LSR_OFFSET)) & COM_LSR_THRE) == 0u)
{
}
io_out8 (com1_port (COM_DATA_OFFSET), value);
}
void
serial_write (const char *text)
{
while (*text != '\0')
{
serial_putc ((u8)*text);
++text;
}
}
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