'===========================================================================
' Subject: POPUP TSR                         Date: Unknown Date (00:00)   
' Author:  Unknown Author(s)                 Code: PB                     
' Keys:    POPUP,TSR                       Packet: PB.ABC
'===========================================================================
'+----------------------------------------------------------------------+
'|   This  program demonstrates a complete popup TSR program known      |
'|   as "ASCTSR" which prints an ASCII chart when ALT-A is pressed.     |
'|  In order to run this program do the following:                      |
'|    1. Load PowerBASIC by typing PB at the DOS prompt.                |
'|    2. Load the file ASCTSR.BAS from the Open option of the           |
'|       File pulldown menu.                                            |
'|    3. Compile by pressing ALT-F9                                     |
'|    4. Exit PowerBASIC by pressing ALT-X                              |
'|    5. Type ASCTSR from the DOS prompt                                |
'|    6. Popup the TSR by pressing ALT-A                                |
'|    7. Popdown the TSR by pressing ESC                                |
'|    8. If you desire, un-install the TSR by pressing                  |
'|       "q" while it is popped down                                    |
'+----------------------------------------------------------------------+

$COMPILE EXE                  ' this tells PB to make a standalone EXE
$LIB IPRINT OFF               ' allow graphic characters to print
$OPTION CNTLBREAK OFF         ' not wise in a tsr

x& = SETMEM(-700000)          ' release unused memory

POPUP KEY CHR$(8,30,247)      ' ALT A is the hot key

POPUP MULTIPLEX &HC000, 254   ' reg AX and DX get this pattern as an ID
REG 1, &HC000 : REG 4, 254    ' set pattern to check for already installed
CALL INTERRUPT &H2F           ' do the multiplex interrrupt
IF REG(1)<>&HC000 AND REG(4)<>254 THEN END 'we were already installed

SwapFile$ = LEFT$(CURDIR$,2)+"\ASCTSR.SWP"

PRINT "ASCII chart available as ALT-A"
REG 1, &HC001 : REG 4, 252  ' Alter AX,DX to show we were here
POPUP SLEEP USING EMS, SwapFile$       ' before going to sleep

WHILE 1=1
x% = POS : y% = CSRLIN
DEF SEG = &hB800
SaveScreen$ = PEEK$(0,4000) ' save the entire screen
IF REG(1)=&HC000 AND REG(4)=254 THEN
LOCATE 12,20
PRINT "+-------------------------------------+";
LOCATE 13,20
PRINT "| ASCTSR example is already installed |";
LOCATE 14,20
PRINT "+-------------------------------------+";
ELSE
GOSUB DisplayAscii
END IF
a$ = INPUT$(1)                               'wait for key to cancel
POKE$ 0, SaveScreen$ :  LOCATE y%, x%        'restore screen
IF UCASE$(A$)="Q" THEN IF POPUP(1) THEN END  'this uninstalls us
REG 1, &HC001 : REG 4, 252  ' Alter AX,DX to show we were here
POPUP SLEEP                 ' before going to sleep
WEND

DisplayAscii:
'put border around
GOSUB BorderColor
LOCATE 3,23
PRINT"+---------------------------------+";
LOCATE 4,23
PRINT "|  PowerBASIC 3.0 can do TSR's!   |";
LOCATE 5,23
PRINT "|  0 1 2 3 4 5 6 7 8 9 A B C D E F|";
FOR y=0 TO &hF
GOSUB BorderColor
LOCATE y+6, 23
PRINT "|";HEX$(y);
LOCATE y+6, 57
PRINT "|";
FOR x=0 TO &hF
GOSUB FieldColor
LOCATE y+6, x*2+25
PRINT " "CHR$(y*16+x);
NEXT
NEXT
GOSUB BorderColor
LOCATE 22,23
PRINT"+---------------------------------+";
RETURN

BorderColor:
COLOR 4,0
RETURN

FieldColor:
COLOR 6,0
RETURN