*
* Copyright (c) 1992-1999 Amiga, Inc.
*
* This example is provided in electronic form by Amiga, Inc. for
* use with the "Amiga ROM Kernel Reference Manual: Devices", 3rd Edition,
* published by Addison-Wesley (ISBN 0-201-56775-X).
*
* The "Amiga ROM Kernel Reference Manual: Devices" contains additional
* information on the correct usage of the techniques and operating system
* functions presented in these examples.  The source and executable code
* of these examples may only be distributed in free electronic form, via
* bulletin board or as part of a fully non-commercial and freely
* redistributable diskette.  Both the source and executable code (including
* comments) must be included, without modification, in any copy.  This
* example may not be published in printed form or distributed with any
* commercial product.  However, the programming techniques and support
* routines set forth in these examples may be used in the development
* of original executable software products for Amiga computers.
*
* All other rights reserved.
*
* This example is provided "as-is" and is subject to change; no
* warranties are made.  All use is at your own risk. No liability or
* responsibility is assumed.
*
****************************************************************************
*
*       InputHandler.a
*
* InputHandler that does a Left/Right mouse button swap...
*
*
* See Swap_Buttons.c for details on how to compile/assemble/link...
*
************************************************************************
*
* Required includes...
*
*       CSECT   InputHandler             ;SAS/Lattice ASM command requires this
*
*       INCDIR  "include:"               ;HX68 requires this

	section	text,code

        INCLUDE "exec/types.i"
        INCLUDE "exec/io.i"
        INCLUDE "devices/inputevent.i"
*
************************************************************************
*
* Make the entry point external...
*
        xdef    _ButtonSwap
*
************************************************************************
*
* This is the input handler that will swap the
* mouse buttons for left handed use.
*
* The event list gets passed to you in  a0.
* The is_Data field is passed to you in a1.
* This example does not use the is_Data field...
*
* On exit you must return the event list in d0.  In this way
* you could add or remove items from the event list.
*
************************************************************************
*
* The handler gets called here...
*
_ButtonSwap:    move.l  a0,-(sp)        ; Save the event list
*
* Since the event list could be a linked list, we start a loop
* here to handle all of the events passed to us.
*
CheckLoop:      move.w  ie_Qualifier(a0),d1             ; Get qualifiers...
                move.w  d1,d0                           ; Two places...
*
* Since we are changing left and right mouse buttons, we need to make
* sure that we change the qualifiers on all of the messages.  The
* left and right mouse buttons are tracked in the message qualifiers
* for use in such things as dragging.  To make sure that we continue
* to drag correctly, we change the qualifiers.
*
CheckRight:     btst    #IEQUALIFIERB_RBUTTON,d1        ; Check for right
                beq.s   NoRight
                bset    #IEQUALIFIERB_LEFTBUTTON,d0     ; Set the left...
                beq.s   CheckLeft
NoRight:        bclr    #IEQUALIFIERB_LEFTBUTTON,d0     ; Clear the left...
*
CheckLeft:      btst    #IEQUALIFIERB_LEFTBUTTON,d1     ; Check for left
                beq.s   NoLeft
                bset    #IEQUALIFIERB_RBUTTON,d0        ; Set the right...
                beq.s   SaveQual
NoLeft:         bclr    #IEQUALIFIERB_RBUTTON,d0        ; Clear the right...
*
SaveQual:       move.w  d0,ie_Qualifier(a0)             ; Save back...
*
* The actual button up/down events are transmitted as the
* code field in RAWMOUSE events.  The code field must the be
* checked and modified when needed on RAWMOUSE events.  If the
* event is not a RAWMOUSE, we are done with it.
*
                cmp.b   #IECLASS_RAWMOUSE,ie_Class(a0)  ; Check for mouse
                bne.s   NextEvent                       ; If not, next...
*
                move.w  ie_Code(a0),d0                  ; Get code...
                move.w  d0,d1                           ; Save...
                and.w   #$7F,d0                         ; Mask UP_PREFIX
                cmp.w   #IECODE_LBUTTON,d0              ; Check for Left...
                beq.s   SwapThem                        ; If so, swap...
                cmp.w   #IECODE_RBUTTON,d0              ; Check for Right...
                bne.s   NextEvent                       ; If not, next...
*
SwapThem:       eor.w   #1,d1                           ; Flip bottom bit
                move.w  d1,ie_Code(a0)                  ; Save it...
*
* The event list is linked via a pointer to the next event
* in the first element of the structure.  That is why it is not
* nessesary to use:  move.l ie_NextEvent(a0),d0
*
* The reason I move to d0 first is that this also checks for zero.
* The last event in the list will have a NULL ie_NextEvent field.
* This is NOT as standard EXEC list where the node after the last
* node is NULL.  Input events are single-linked for performance.
*
NextEvent:      move.l  (a0),d0                         ; Get next event
                move.l  d0,a0                           ; into a0...
                bne.s   CheckLoop                       ; Do some more.
*
* All done, just return the event list...  (in d0)
*
                move.l  (sp)+,d0        ; Get event list back...
                rts                     ; return from handler...
*
*                                       ; SAS/Lattice ASM command requires this
                END