Stack Overflow - Stack Underflow

[massive attack]

'===============================================================================
@ device  INTRC_OSC_NOCLKOUT
@ device  wdt_off
@ device  pwrt_on
@ device  protect_off
include "Tanimlar.inc"
'===============================================================================
Ana:
   gosub Chk_KEYPAD
   if say = 3 then 
        gosub kilit
   endif
   pause 1
goto Ana
'===============================================================================
Chk_KEYPAD:
   for row = 0 to 3 
      PORTB = (dcd row) ^ $f    
      pause 1
      col = PORTB >> 4
      if (col <> $f) then       'tuşa basıldı 
         key = (row * 3) + (ncd (col ^ $f))
         low buz 
         pause 70
         high buz
         while (PORTB >> 4) <> $f  
            pause 1
         wend
         if key = 11 then key = 0
         TusBuff[tussay] = key
         if psw.0 = 0 then
             gosub Chk_tussay
         else
             gosub chk_tussay2
         endif
         key = 255
      endif
   next 
return    
'===============================================================================
Beep:
   high ld1
   low buz 
   pause 70
   high buz 
   pause 70
   low buz
   pause 70
   low ld1
   high buz
return
'===============================================================================
Chk_SfrOK: 
   psw.1 = 0
   psw.2 = 0 
   psw.3 = 0
   psw.4 = 0 
   psw.5 = 0
   psw.6 = 0 
   if (TusBuff[0] = SfrBuff[0]) and (TusBuff[1] = SfrBuff[1]) and (TusBuff[2] = SfrBuff[2]) and (TusBuff[3] = SfrBuff[3]) then psw.1 = 1 
   if (TusBuff[0] = SfrBuff[4]) and (TusBuff[1] = SfrBuff[5]) and (TusBuff[2] = SfrBuff[6]) and (TusBuff[3] = SfrBuff[7]) then psw.2 = 1
   if (TusBuff[0] = SfrBuff[8]) and (TusBuff[1] = SfrBuff[9]) and (TusBuff[2] = SfrBuff[10]) and (TusBuff[3] = SfrBuff[11]) then psw.3 = 1
   if (TusBuff[0] = SfrBuff[12]) and (TusBuff[1] = SfrBuff[13]) and (TusBuff[2] = SfrBuff[14]) and (TusBuff[3] = SfrBuff[15]) then psw.4 = 1
   if (TusBuff[0] = SfrBuff[16]) and (TusBuff[1] = SfrBuff[17]) and (TusBuff[2] = SfrBuff[18]) and (TusBuff[3] = SfrBuff[19]) then psw.5 = 1
   if (TusBuff[0] = MKSfrBuff[0]) and (TusBuff[1] = MKSfrBuff[1]) and (TusBuff[2] = MKSfrBuff[2]) and (TusBuff[3] = MKSfrBuff[3]) then psw.6 = 1
   if psw.1 = 0 and psw.2 = 0 and psw.3 = 0 and psw.4 = 0 and psw.5 = 0 and psw.6 = 0 then
        if TusBuff[tussay] = 12 or TusBuff[tussay] = 10 then           
            if psw.6 = 0 then
                gosub Hata
            endif
        endif
   endif
return   
'===============================================================================
Chk_NewSfrOK:
   psw.1 = 0
   psw.2 = 0
   psw.3 = 0
   psw.4 = 0
   psw.5 = 0
   psw.6 = 0
   if (TusBuff[5] = TusBuff[10]) and (TusBuff[6] = TusBuff[11]) and (TusBuff[7] = TusBuff[12]) and (TusBuff[8] = TusBuff[13]) then 
        psw.1 = 1
        psw.6 = 1
   endif
return 
'===============================================================================
Sifre_Degis:   
    if psw.1 then 
       SfrBuff[0] =  TusBuff[5]
       SfrBuff[1] =  TusBuff[6]
       SfrBuff[2] =  TusBuff[7]
       SfrBuff[3] =  TusBuff[8]
    endif
    if psw.2 then
       SfrBuff[4] =  TusBuff[5]
       SfrBuff[5] =  TusBuff[6]
       SfrBuff[6] =  TusBuff[7]
       SfrBuff[7] =  TusBuff[8]
    endif
    if psw.3 then
       SfrBuff[8] =  TusBuff[5]
       SfrBuff[9] =  TusBuff[6]
       SfrBuff[10] =  TusBuff[7]
       SfrBuff[11] =  TusBuff[8]
    endif
    if psw.4 then
       SfrBuff[12] =  TusBuff[5]
       SfrBuff[13] =  TusBuff[6]
       SfrBuff[14] =  TusBuff[7]
       SfrBuff[15] =  TusBuff[8]
    endif
    if psw.5 then
       SfrBuff[16] =  TusBuff[5]
       SfrBuff[17] =  TusBuff[6]
       SfrBuff[18] =  TusBuff[7]
       SfrBuff[19] =  TusBuff[8]
    endif
    
   Write 0, SfrBuff[0]       'Yeni şifre EEprom'un 0..3 adreslerine kaydedildi
   Write 1, SfrBuff[1]
   Write 2, SfrBuff[2]
   Write 3, SfrBuff[3]
   Write 4, SfrBuff[4]       'Yeni şifre EEprom'un 0..3 adreslerine kaydedildi
   Write 5, SfrBuff[5]
   Write 6, SfrBuff[6]
   Write 7, SfrBuff[7]
   Write 8, SfrBuff[8]       'Yeni şifre EEprom'un 0..3 adreslerine kaydedildi
   Write 9, SfrBuff[9]
   Write 10, SfrBuff[10]
   Write 11, SfrBuff[11]
   Write 12, SfrBuff[12]       'Yeni şifre EEprom'un 0..3 adreslerine kaydedildi
   Write 13, SfrBuff[13]
   Write 14, SfrBuff[14]
   Write 15, SfrBuff[15]
   Write 16, SfrBuff[16]       'Yeni şifre EEprom'un 0..3 adreslerine kaydedildi
   Write 17, SfrBuff[17]
   Write 18, SfrBuff[18]
   Write 19, SfrBuff[19]
return
'===============================================================================
Chk_tussay: 
   select case tussay
      case 4
         gosub Chk_SfrOK       
         if psw.1 or psw.2 or psw.3 or psw.4 or psw.5 or psw.6 then 
            if TusBuff[tussay] = 12 then Kilit_acik
            if TusBuff[tussay] <> 10 then Clr_TusBuff
            gosub Beep
         else
            gosub Clr_TusBuff
         endif
      case 9
         if TusBuff[tussay] <> 12 then Clr_TusBuff
         gosub Beep 
      case 14
         if psw.6 = 0 then
             if TusBuff[tussay] <> 12 then Clr_TusBuff
             gosub Beep
             gosub Chk_NewSfrOK   
             if psw.1 or psw.6 then 
                gosub Beep
                gosub Sifre_Degis
                gosub Beep
                gosub Clr_TusBuff
             else
                gosub Clr_TusBuff
             endif 
         endif
      case 16
         if TusBuff[tussay] <> 12 then clr_TusBuff
         gosub beep
         gosub Chk_NewSfrOK   
         if psw.6 then 
            gosub Beep
            gosub Sifre_Degis
            gosub Beep
            gosub Clr_TusBuff
         else
            gosub Clr_TusBuff
         endif    
      case else
         if TusBuff[tussay] = 12 then Clr_TusBuff
   end select
   tussay = tussay + 1   
return
'===============================================================================
Chk_tussay2: 
   select case tussay
      case 4
         if psw.6 then 
            psw.0 = 0
            if TusBuff[tussay] = 12 then Kilit_acik
            if TusBuff[tussay] <> 10 then Clr_TusBuff
            gosub Beep
         else
            gosub Clr_TusBuff
         endif
      case 9
         if TusBuff[tussay] <> 12 then Clr_TusBuff
         gosub Beep 
      case 14
         if TusBuff[tussay] <> 12 then Clr_TusBuff
         gosub Beep
         gosub Chk_NewSfrOK   
         if psw.6 then 
            gosub Beep
            gosub Sifre_Degis
            psw.0 = 0
            gosub Beep
            gosub Clr_TusBuff
         else
            gosub Clr_TusBuff
         endif    
      case else
         if TusBuff[tussay] = 12 then Clr_TusBuff
   end select
   tussay = tussay + 1    
return
'===============================================================================
Reset:
    for cnt = 0 to 14 
        TusBuff[cnt] = cnt 
    next
    low ld1
    high buz
    tussay = 0 
    psw.0 = 0
    psw.1 = 0
    psw.6 = 0
    say = 0
    return   
'===============================================================================
Hata:
    say = say + 1
    high ld1
    low buz
    pause 200
    low ld1
    high buz
    return
'===============================================================================
Kilit_acik:
   if psw.0 = 0 then 
   say = 0
   high mtr             ' motoru çalıştır
   High frw             ' İleri dön
   pause Frw_time       ' ileri dönme süresi
   low frw              
   low mtr
   pause wait_time      ' bekleme süresi 
   high mtr             ' motoru çalıştır
   high BCK             ' geriye dön
   pause bck_time       ' geriye dönme süresi
   low BCK 
   low mtr
   endif                                        
   gosub Reset
   return
'===============================================================================
Clr_TusBuff:
   for cnt = 0 to 14 
      TusBuff[cnt] = cnt 
   next
   tussay = 0 
   gosub Ana
'===============================================================================
Kilit :
    psw.0 = 1 
    low buz
    high ld1
    gosub chk_KEYPAD    
    gosub Kilit
end 
'===============================================================================

when simulating in proteus, errors occur:
Stack overflow executing CALL instruction;
the device is PIC16F628A
What's wrong?