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Index > DOS > FreeDOS BUG: brew temp file AH=$5A + re-create it AH=$3C

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DOS386



Joined: 08 Dec 2006
Posts: 1901
DOS386
Code:
; FreeDOS "Brew-temp-file-BUG" test | (CL) 2009 | 91 Bytes

define pope  pop
define popef popf

macro movntq mdst, msrc {
  if mdst eq cs
    err "CS is not a valid destination"
  end if
  if mdst in <ds,es,ss> & msrc in <cs,ds,es,ss>
    push  msrc
    pope  mdst
  else
    if mdst in <ax,bx,cx,dx,si,di,bp> & msrc eq 0
      xor  mdst, mdst
    else
      mov  mdst, msrc
    end if
  end if
} ; endmacro

format binary as "COM"
use16
org $0100

        mov    ah, $5A
        mov    dx, buff
        movntq cx, 0
        int    $21            ; Brew temp
        jc     short er
        mov    si, buff
        call   pr             ; Boast
        call   eol
        mov    ah, $3C
        mov    dx, buff
        int    $21            ; Re-Create it
        jc     short er
        mov    bx, ax         ; He
        mov    cx, 9999
        mov    di, buff
        mov    dx, di
@@:     mov    [di], di
        inc    di
        inc    di
        loop   short @b
        mov    ah, $40
        mov    cx, 19998
        int    $21            ; WRTFF
        jc     short er
        mov    ah, $3E
        int    $21            ; Closed: IS a BUG
        jc     short er
        ret
        ;----

er:     mov    si, fu

pr:     lodsb
        cmp    al, 0
        je     short @f
        xchg   ax, dx
        mov    ah, 2
        int    $21
        jmp    short pr
        ;--------------
@@:     ret
        ;----

eol:    mov    si, qeol
        jmp    short pr
        ;--------------

qeol:   db     13,10,0
fu:     db     "error"

buff:   db 0
    


This works in EDR-DOS but in FreeDOS it leaves an empty file + a dead cluster chain, BUG persists in 2038 kernel, to be fixed ASAP Neutral

Problem formerly known as IUP-BUG, but above 91 Bytes are sufficient to reproduce it. Smile
Post 18 Jun 2009, 11:55
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