;debug when read FDD
code segment 'code'
assume cs:code
      alt equ 038h
      tab equ 0fh
      int_num equ 0d0h
      int_vec equ int_num*4h
magic_key proc far
org 100h
start:jmp begin
newirq0 db int_num

int0e_begin proc near
push ds
push es
push ax
push bx
mov ax,0
mov es,ax
mov ax,cs
mov es:[102h],ax
lea ax,cs:int13_begin
mov es:[100h],ax
pop bx
pop ax
pop es
pop ds
ret
int0e_begin endp

int13_begin:
cmp ax,0201h
jnz zz
cmp dl,0
jz to_debug
zz:
jmp dword ptr cs:old_int13

to_debug:
mov al,0
out 21h,al
push es
mov ax,0
mov es,ax
mov ax,es:[4]
mov es:[204h],ax
mov ax,es:[6]
mov es:[206h],ax
mov ax,es:[200h]
mov es:[4h],ax
mov ax,es:[202h]
mov es:[6h],ax
pop es
pushf
pop ax
or ax,300h
push ax
popf
nop
nop
nop
nop
nop
nop
nop
nop
jmp aaa
;iret
old_int13 dw ?
a dw ?


newirqvec dw int_vec
irq0:int 08h
     iret
irq1:int 09h
     iret
irq2:int 0ah
     iret
irq3:int 0bh
     iret
irq4:int 0ch
     iret
irq5:int 0dh
     iret
irq6:
;call int0e_begin
jmp to_debug
aaa:
int 0eh
push ax
push cx
push si
push di
push es
push ds
mov ax,0b800h
mov es,ax
mov si,0
mov di,0
mov cx,100h
rep movsb

mov ax,0
mov ds,ax
mov ax,8000h
mov es,ax
mov cx,400h
mov di,0
mov si,0
rep movsb

pop ds
pop es
pop di
pop si
pop cx
pop ax

iret
irq7:int 0fh
     iret

set_irq proc
mov si,cs:newirqvec
mov ax,0
mov es,ax

lea ax,irq0
mov es:[si],ax
mov es:[si+2h],cs

lea ax,irq1
mov es:[si+4h],ax
mov es:[si+6h],cs

lea ax,irq2
mov es:[si+8h],ax
mov es:[si+0ah],cs

lea ax,irq3
mov es:[si+0ch],ax
mov es:[si+0eh],cs

lea ax,irq4
mov es:[si+10h],ax
mov es:[si+12h],cs

lea ax,irq5
mov es:[si+14h],ax
mov es:[si+16h],cs

lea ax,irq6
mov es:[si+18h],ax
mov es:[si+1ah],cs

lea ax,irq7
mov es:[si+1ch],ax
mov es:[si+1eh],cs

cli
mov al,11h
out 20h,al
jmp de1
de1:
mov al,cs:newirq0
out 21h,al
jmp de2

de2:
mov al,4
out 21h,al
jmp de3

de3:
mov al,1
out 21h,al
jmp de4

de4:
mov al,0
out 21h,al

sti
ret
set_irq endp

begin:
push es
push cs
pop ds
call set_irq
pop es

mov ax,cs
mov ds,ax
mov ah,35h
mov al,40h
int 21h
mov ax,es
mov old_int13,bx
mov old_int13+2,ax

lea dx,end_add
add dx,101h
int 27h
end_add:
magic_key endp
code ends
end start