.org 0x7C00
.code16

start:
movw %cs, %ax
movw %ax, %ds
movw %ax, %ss
movw start, %sp
call clean_screen

load_kernel:
movw $0x1100, %ax
movw %ax, %es
movw $0x00, %bx
movb $0x02, %ah
movb $1, %dl
movb $0, %dh
movb $0, %ch
movb $2, %cl #Pointer to raw data
movb $15,%al #Size of raw data
int $0x13

movw $0x1300, %ax
movw %ax, %es
movw $0x0, %bx
movb $0x02, %ah
movb $1, %dl
movb $0, %dh
movb $0, %ch
movb $17, %cl #Pointer to raw data
movb $2,%al #Size of raw data
int $0x13

movw $0x1360, %ax
movw %ax, %es
movw $0x00, %bx
movb $0x02, %ah
movb $1, %dl
movb $0, %dh
movb $1, %ch
movb $1, %cl #Pointer to raw data
movb $18,%al #Size of raw data
int $0x13

movw $0x1660, %ax
movw %ax, %es
movw $0x00, %bx
movb $0x02, %ah
movb $1, %dl
movb $1, %dh
movb $0, %ch
movb $1, %cl #Pointer to raw data
movb $18,%al #Size of raw data
int $0x13

movw $0x1960, %ax
movw %ax, %es
movw $0x00, %bx
movb $0x02, %ah
movb $1, %dl
movb $0, %dh
movb $1, %ch
movb $1, %cl #Pointer to raw data
movb $17,%al #Size of raw data
int $0x13


movw $hello_string, %bx
call puts
hello_world:
movb $0, %ah
int $0x16
cmpb $32, %al
je clean_screen_hello
jne hello_world

print_string:
movw $alphabet_copy, %bx
movw $alphabet_string, %cx
call puts
jmp input_letters

output_string:
movw $alphabet_string, %ax
movw %ax, %es
movw $0, %bx
movb $3, %ah
movb $1, %dl
movb $0x00, %dh
movb $0, %ch
movb $0x01, %cl  #Pointer to raw data
movb $1, %al  #size of raw data
int $0x13

before_ProtectedMode:
cli
lgdt gdt_info
inb $0x92, %al
orb $2, %al
outb %al, $0x92
movl %cr0, %eax
orb $1, %al
movl %eax, %cr0
ljmp $0x8, $protected_mode

input_letters:
movb $0, %ah
int $0x16
cmpb $0x0D, %al
je output_string #If a symbol was "Enter"

inf_loop:
cmpb 0(%bx), %al
je delete_letter
addw $1, %bx
addw $1, %cx
jmp inf_loop

delete_letter:
movw %cx, %bx
movb 0(%bx), %ah
cmpb $0x5F, %ah
je swap
movb $0x5F, %ah
movb %ah, 0(%bx)
call clean_screen
movw $alphabet_string, %bx
movw $alphabet_string, %cx
call puts
jmp input_letters

swap:
movb %al, 0(%bx)
call clean_screen
movw $alphabet_string, %bx
movw $alphabet_string, %cx
call puts
jmp input_letters

alphabet_string:
    .asciz "abcdefghijklmnopqrstuvwxyz"
alphabet_copy:
    .asciz "abcdefghijklmnopqrstuvwxyz"
hello_string:
    .asciz "Hello, it's Dict_OS' bootloader, if u want to enter letter, press space!"
puts:
movb 0(%bx), %al
test %al, %al
jz end_puts
movb $0x0e, %ah
int $0x10
addw $1, %bx
jmp puts

end_puts:
movw $alphabet_copy, %bx
ret

clean_screen:
movb $0, %ah
movb $2, %al
int $0x10
ret
clean_screen_hello:
xorw %bx,%bx
movb $0, %ah
movb $2, %al
int $0x10
jmp print_string
gdt:
.byte 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
.byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x9A, 0xCF, 0x00
.byte 0xff, 0xff, 0x00, 0x00, 0x00, 0x92, 0xCF, 0x00
gdt_info:
.word gdt_info - gdt
.word gdt, 0

.code32
protected_mode:
# Здесь идут первые инструкции в защищенном режиме
movw $0x10, %ax
movw %ax, %es
movw %ax, %ds
movw %ax, %ss
call 0x11000

.zero (512 - (. - start) - 2)
.byte 0x55, 0xAA