$CPU 8086          ' make compatible with XT systems
$LIB ALL OFF       ' turn off all PowerBASIC libraries
$ERROR ALL OFF     ' turn off all PowerBASIC error checking
$OPTIMIZE SIZE     ' optimize for smaller code
 $COMPILE UNIT      ' compile to a UNIT (.PBU)
'$COMPILE EXE       ' compile to a UNIT (.PBU)

DEFINT A-Z         ' Required for all numeric functions, forces PB to not
                   ' include floating point in UNIT (makes it smaller)
'/*------------------------------------------------------------------*/
$CODE SEG "MLIB5"
'/*------------------------------------------------------------------*/
' ISCDROM()
'     Is CD ROM drive present.
'     Returns 1 if CDROM is found.
'     Returns 0 if not.
'     EXAMPLE:  T = ISCDROM
'/*------------------------------------------------------------------*/
FUNCTION ISCDROM() PUBLIC AS INTEGER
    ASM PUSH AX
    ASM PUSH CX
    ASM PUSH DX
    ASM PUSH ES
    ASM PUSH DI
    REG 1, &H1500
    CALL INTERRUPT &H2F      'CALL TO MSCDEX TO CHECK FOR CD-ROM DRIVES
    AL = REG(1) AND 255      'IF AL = 255, MSCDEX IS LOADED
    BL = REG(2) AND 255      'BL IS NUMBER OF CD-ROM DRIVES ON MACHINE
    CL = REG(3) AND 255      'CL IS NUMBER OF FIRST CD-ROM DRIVE (ZERO BASED)
    ASM POP DI
    ASM POP ES
    ASM POP DX
    ASM POP CX
    ASM POP AX
    IF AL = 255 AND BL > 0 THEN
      FUNCTION = 1
'/*   T$ = "CD-ROM(S): "+ STR$(BL) +" DRIVE"
'/*   IF BL > 1 THEN T$ = T$ +"S BEGINNING AT"
'/*   T$ = T$ + " "+CHR$(CL + 65)+":"
    ELSE
      FUNCTION = 0
'/*   PRINT "MSCDEX NOT LOADED.  NO CD-ROM DRIVES FOUND."
    END IF
'/* FUNCTION = T$
  END FUNCTION
'/*------------------------------------------------------------------*/
'  $INCLUDE "C:\CODE\MLIB\MLIB.INC"
'  PRINT ISCDROM
'  Y$ = GETKEY