**********************************************************************
*    Program: QMOUSE - CLI "IF" test for mouse button
*    Author:  Robert Rethemeyer, Sunnyvale, CA
*    Date:    10/05/86
*    Status:  RELEASED TO THE PUBLIC DOMAIN, "AS-IS"
**********************************************************************
* QMOUSE is a program to query the status of the left mouse button.
* It sets a return code of 0 if the button is NOT pressed,
* or a return code of 8 if it IS pressed.  This return code can
* be used as a WARN condition in a CLI "execute" file.
*
* QMOUSE provides a way to optionally alter the way that
* "startup-sequence" operates when booting the machine.
* For example, some DOS 1.2 users load the most frequently used
* commands into RAM disk in the startup-sequence.  Since that
* lessens the total memory available, some programs will not run.
* These users usually must keep a separate Workbench disk which
* does not load the RAM.  Using QMOUSE and an IF statement in the
* startup-sequence, the loading of RAM can be conditionally skipped.
* Do nothing during the startup to load the RAM as usual;  hold
* down the button to not load the RAM if extra RAM will be needed.
* Imaginative users may think of other uses for QMOUSE.
*
* When pressing the button, be sure the mouse pointer is off of the
* drag bar, otherwise the execution of the file pauses.
* Here is a basic example of how to use QMOUSE in the startup-sequence:
*
*          echo "Workbench 1.2"
*          ... etc....
*          echo "<Hold down mouse-left for more RAM>"
*          wait 1 sec
*          QMouse
*          IF NOT WARN
*          echo "Loading RAM:C"
*          makedir RAM:C
*          path ....etc...
*          copy c:dir to ram:c
*          copy ....etc...
*          ELSE  
*          echo "RAM:C not present"
*          ENDIF
*         
********************* Begin text of program **************************
         NOLIST
         INCLUDE "hardware/cia.i"
         LIST
         XREF    _ciaa                 * location of 8520 chips
**********************************************************************
QMouse:
         MOVEA.L #_ciaa,a3             * address of chip register
         MOVE.B  ciapra(a3),d0         * get register data
         AND.L   #CIAF_GAMEPORT0,d0    * mask out mouse button bit
         EOR.B   #CIAF_GAMEPORT0,d0    * invert it
         LSR.B   #3,d0                 * shift to bit 3
         RTS                           * return with bit as return code
         END