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/*
RCC-Project
Copyright (C) 2026 Richard Qin
This file is part of RCC-Project.
*/
#include "bios.h"
#include "io.h"
#include "regs.h"
#define COM1_BASE 0x03F8u
#define COM_DATA 0x00u
#define COM_LSR 0x05u
#define COM_LSR_THRE 0x20u
#define COM_LSR_IDLE 0x40u
static void
int14_putc (u8 value)
{
while ((io_in8 ((u16)(COM1_BASE + COM_LSR)) & COM_LSR_THRE) == 0u)
{
}
io_out8 ((u16)(COM1_BASE + COM_DATA), value);
}
void
int14_service (struct bios_regs *regs)
{
u8 function;
u8 status;
function = (u8)(regs->eax >> 8);
if (function == 0x00u)
{
serial_init ();
regs->eax &= 0xFFFF0000u;
return;
}
if (function == 0x01u)
{
int14_putc ((u8)regs->eax);
status = (u8)(io_in8 ((u16)(COM1_BASE + COM_LSR))
| COM_LSR_THRE | COM_LSR_IDLE);
regs->eax = (regs->eax & 0xFFFF00FFu) | ((u32)status << 8);
return;
}
if (function == 0x03u)
{
status = io_in8 ((u16)(COM1_BASE + COM_LSR));
regs->eax = (regs->eax & 0xFFFF00FFu) | ((u32)status << 8);
return;
}
regs->eax = 0x0100u;
}
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