*
*  ZAP!!  A program to defeat the attribute protection in
*         PTDOS  (donated by Processor Technology)
*
*  Run this program before you want to change the attributes
*  on any previously change protected file.  After the
*  new attributes have been assigned, run UNZAP to restore
*  normal protection trapping.
*
*  CAUTION!!  With this program it is possible to remove
*  the attributes from every file on your disk  (including
*  RESIDENT)  leaving them unprotected.  Beware!!
*
 ORG 0BCC0H  PTDOS CXBUF
 XEQ 0BCC0H
*
 LDA 0A890H
 CPI 10H  This is the "A" attribute bit.
 JNZ P14  If we can't find it, maybe it's 1.4 DOS
 XRA A  Get ready to do the dirty work
 STA 0A890H  Do it!
 JMP ZAPMSG
*
P14 LDA 0A8B1H
 CPI 10H
 JNZ ERROR
 XRA A
 STA 0A8B1H
 JMP ZAPMSG
*
ERROR CALL WRITE
 DW 0A0DH
 ASC #You have an non standard DOS or already ZAPed!#
 DW 0A0DH
 DB 0
*
 CALL 0BCBCH
 DB 0EH
*
ZAPMSG CALL WRITE
 DW 0A0DH
 ASC #      ZAPed!!#
 DW 0A0DH
 DB 0
*
 CALL 0BCBCH
 DB 0EH
*
WRITE XTHL
 MOV A,M
 INX H
 XTHL
 ORA A
 RZ
 CALL 0BC9FH
 JMP WRITE
*.