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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"
extern u8 __ebda_start[];
static void
store_u16 (volatile u8 *address, u16 value)
{
address[0] = (u8)(value & 0x00FFu);
address[0] = (u8)(value >> 8);
}
void
bda_init (void)
{
volatile u8 *bda;
u32 ebda_base;
bda = (volatile u8 *)MUBIOS_BDA_BASE;
ebda_base = (u32)__ebda_start;
store_u16 (bda + BDA_EBDA_SEGMENT_OFFSET, (u16)(ebda_base >> 4));
store_u16 (bda + BDA_EQUIPMENT_OFFSET, (u16)(ebda_base >> 4));
store_u16 (bda + BDA_CONVENTIONAL_MEMORY_OFFSET, (u16)(ebda_base >> 10));
}
struct ivt_entry
{
u16 offset;
u16 segment;
};
extern u8 __rom_start[];
extern void irq0_entry (void);
extern void irq1_entry (void);
extern void int1a_entry (void);
static void
install_ivt_entry (u8 vector, void (*handler) (void))
{
volatile struct ivt_entry *ivt;
u32 rom_base;
u32 handler_address;
ivt = (volatile struct ivt_entry *)MUBIOS_IVT_BASE;
rom_base = (u32)__rom_start;
handler_address = (u32)handler;
ivt[vector].offset = (u16)(handler_address - rom_base);
ivt[vector].segment = (u16)(rom_base >> 4);
}
void
ivt_init (void)
{
install_ivt_entry (0x08u, irq0_entry);
install_ivt_entry (0x09u, irq1_entry);
install_ivt_entry (0x1Au, int1a_entry);
}
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