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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/>.
.intel_syntax noprefix
.code16
.section .text16.irq, "ax"
.global int1a_entry
.type int1a_entry, @function
int1a_entry:
cmp ah, 0x00
jne int1a_return
push ds
push bx
xor bx, bx
mov ds, bx
mov bx, 0x046C
mov cx, word ptr [bx + 2]
mov dx, word ptr [bx]
mov al, byte ptr [0x0470]
mov byte ptr [0x0470], 0
mov ah, 0x00
pop bx
pop ds
int1a_return:
iret
.global int10_entry
.type int10_entry, @function
int10_entry:
cmp ah, 0x0E
jne int10_return
push bp
mov bp, sp
push ax
push bx
push dx
push si
push di
push ds
push es
xor ax, ax
mov ds, ax
mov ax, 0xB800
mov es, ax
mov si, 0x0050
mov dx, word ptr [si]
mov al, byte ptr [bp - 2]
mov bl, byte ptr [bp - 4]
cmp al, 0x0D
je int10_carriage_return
cmp al, 0x0A
je int10_line_feed
cmp al, 0x08
je int10_backspace
mov di, dx
shl di, 1
mov ah, bl
mov word ptr es:[di], ax
inc dx
jmp int10_store_cursor
int10_carriage_return:
mov ax, dx
mov si, 80
xor dx, dx
div si
mul si
mov dx, ax
jmp int10_store_cursor
int10_line_feed:
add dx, 80
jmp int10_store_cursor
int10_backspace:
cmp dx, 0
je int10_store_cursor
dec dx
mov di, dx
shl di, 1
mov al, 0x20
mov ah, bl
mov word ptr es:[di], ax
int10_store_cursor:
cmp dx, 2000
jb int10_save_cursor
xor dx, dx
int10_save_cursor:
mov word ptr [0x0050], dx
pop es
pop ds
pop di
pop si
pop dx
pop bx
pop ax
pop bp
int10_return:
iret
.global int13_entry
.type int13_entry, @function
int13_entry:
int13_entry:
cmp ah, 0x41
jne int13_return
push bp
mov bp, sp
cmp bx, 0x55AA
jne int13_fail
mov bx, 0xAA55
mov cx, 0x0001
mov ax, 0x3000
# Clear CF in the FLAGS saved by INT.
and word ptr [bp + 6], 0xFFFE
pop bp
iret
int13_fail:
mov ah, 0x01
# Set CF in the FLAGS saved by INT.
or word ptr [bp + 6], 0x0001
pop bp
iret
int13_return:
iret
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