17 Bit Software 3: The Continuation

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Assembly Source File | 1994-01-27 | 8.6 KB | 260 lines

TTL MiddleButton * ******************************************************************************* * * * MiddleButton * * * * Copyright (c) 1989 by Michael Sinz MKSoft Development * * * * AmigaDOS EXEC release 1.2 or greater... * * * ******************************************************************************* * * * To assemble, I used the assembler that comes with MANX C68K * * * * It should assemble without any problems on most 680x0 assemblers * * The code is position independant and thus needs an assembler that * * can produce such files. * * * ******************************************************************************* * * * This program installs a handler into the input food chain. * * The handler converts the middle mouse button (for those of you * * with such animals) into a shift key for all mouse events. * * * * Thus, when you hold the middle button down, you can "SHIFT-SELECT" * * using just the mouse. Some programs also give you an extended * * select mode when you click the mouse and push the shift key. * * Only mouse events are modified to have the shift key qualifier. * * * * When you run this program, it will take 80 bytes of system memory * * to install and link in the handler code. It then exits... * * * ******************************************************************************* * * The following INCLUDE files are needed to make this program assemble. * They come with the Amiga Macro-Assembler Package. * NOMLIST ; No macro expansion list NOCLIST ; No conditional list NOLIST ; No need to list these INCLUDE "EXEC/Types.i" INCLUDE "EXEC/Libraries.i" INCLUDE "EXEC/Interrupts.i" INCLUDE "EXEC/Memory.i" INCLUDE "EXEC/IO.i" INCLUDE "EXEC/Ables.i" INCLUDE "Libraries/DOSextens.i" INCLUDE "Devices/Input.i" INCLUDE "Devices/InputEvent.i" LIST ; Ok, lets start the listing * ******************************************************************************* * * This is the only fixed address in the system and it even "floats"... * xref _AbsExecBase * ******************************************************************************* * * Some macros that make calling the system routines easier... * CALLSYS MACRO xref _LVO\1 ; Set the external reference CALLLIB _LVO\1 ; Call the EXEC definied macro ENDM * ******************************************************************************* * * * Register usage through this system... * * * * a0 - Scrap * * a1 - Scrap * * a2 - IO Block * * a3 - MsgPort * * a4 - Task * * a5 - New Memory * * a6 - ExecBase pointer * * a7 - Stack pointer... What else? * * * * d0 - Scrap * * d1 - Scrap * * d2 - Scrap * * d3 - Scrap * * d4 - Scrap * * d5 - Scrap * * d6 - Scrap * * d7 - Zero... * * * ******************************************************************************* * * Now, for the start of the code... * MiddleButton: move.l _AbsExecBase,a6 ; Get the EXEC library base * clr.l d7 ; Clear d7... * move.l d7,a1 ; Clear a1 CALLSYS FindTask ; Get our task pointer... move.l d0,a4 ; Now, move it to a1 for addressing use lea pr_MsgPort(a4),a3 tst.l pr_CLI(a4) ; Check if this is a CLI task... bne.s QuickCLI ; If so, skip the next section * ******************************************************************************* * * This section deals with starting from the WorkBench... * It is just here for completeness... * QuickWorkBench: move.l a3,a0 ; Get message port CALLSYS WaitPort ; Wait for the WorkBench message... move.l a3,a0 ; ...it's here, so let's get it CALLSYS GetMsg ; off the message port... bra.s QuickCont ; ...and go to the continue routine * ******************************************************************************* * * The routine was started from the CLI (prefered) * Let's store a NULL pointer so that there is no WB message... * QuickCLI: move.l d7,d0 ; No reply message... * ******************************************************************************* * * Continue with the Quick initialization * QuickCont: move.l d0,-(sp) ; Save the message pointer... * lea InputBlock(pc),a2 ; Get the I/O block move.b #NT_MESSAGE,LN_TYPE(a2) ; initialize it... move.w #IOSTD_SIZE,MN_LENGTH(a2) move.l a3,MN_REPLYPORT(a2) ; Our reply port... * lea inputName(pc),a0 ; Get input.device name move.l d7,d0 ; Clear d0 move.l d7,d1 ; and d1 move.l a2,a1 CALLSYS OpenDevice ; a1 is still set to the I/O block tst.l d0 bne.s abortNoInput * ******************************************************************************* * * We now allocate and copy the handler... * move.l #CodeSize,d0 ; Size of memory move.l d0,d6 ; Save it... move.l #MEMF_PUBLIC,d1 ; Type of memory CALLSYS AllocMem ; Get the memory move.l d0,a5 ; Save it... tst.l d0 ; Check it... beq.s NormalExit ; No memory, no copy... move.l d0,a1 ; Destination... lea StartOfCode(pc),a0 ; Source CopyLoop: move.b (a0)+,(a1)+ ; Copy it... dbra d6,CopyLoop ; All of it... * ******************************************************************************* * * We also need to add our own input handler into the food chain... * move.l a5,a0 ; Start of new code... add.l #HandlerOffset,a0 ; Pointer to handler move.b #60,LN_PRI(a0) ; Handler priority move.l a5,IS_DATA(a0) ; Handler data addq.l #2,a5 ; Point to code... move.l a5,IS_CODE(a0) ; Handler code move.l a2,a1 ; Get i/o block move.l a0,IO_DATA(a1) ; Set the data address... move.w #IND_ADDHANDLER,IO_COMMAND(a1) ; the ADD command... CALLSYS DoIO ; All set, handler is running * ******************************************************************************* * * The standard exit routines... * Close anything that we have opened... * NormalExit: move.l a2,a1 ; Get I/O block... CALLSYS CloseDevice ; Close the thing... abortNoInput: move.l (sp)+,d0 ; Get that message back beq.s abortNoWB ; If none, we are done move.l d0,a1 ; Get the pointer ready FORBID ; manual says we must forbid... CALLSYS ReplyMsg ; ...when returning WB message abortNoWB: rts ; RTS out of this task... * ******************************************************************************* * * The input block... * InputBlock: ds.b IOSTD_SIZE * ******************************************************************************* * * This is the mouse accel value... * StartOfCode: dc.w 0 ; Flag value for shift key... * ******************************************************************************* * * This is the handler... It is the hardest working piece of code here... * MyHandler: move.l a0,-(sp) ; We MUST save what we play with... * ******************************************************************************* * * Now, for the handler loop... We will look at every event that has been given * to us. * HandlerLoop: cmpi.b #IECLASS_RAWMOUSE,ie_Class(a0) ; Check for mouse... bne.s HandlerNext ; If skip it... * * if IECODE_MBUTTON... IECODE_UP_PREFIX... move.w ie_Code(a0),d0 ; Get code... cmpi.w #IECODE_MBUTTON,d0 ; Check if button is pushed... bne.s NotDown ; Middle button not down... * move.w #IEQUALIFIER_LSHIFT,(a1) ; Store the left shift bra.s HandlerCont ; and continue * NotDown: cmpi.w #(IECODE_MBUTTON+IECODE_UP_PREFIX),d0 ; Button up? bne.s HandlerCont ; If not, skip clr.w (a1) ; Clear code... * HandlerCont: move.w ie_Qualifier(a0),d0 ; Get qualifier... or.w (a1),d0 ; or in the shift value... move.w d0,ie_Qualifier(a0) ; Store it... * HandlerNext: move.l ie_NextEvent(a0),d0 ; Get next event... move.l d0,a0 bne.s HandlerLoop ; Go back and do this one... * move.l (sp)+,d0 ; Restore our stuff... d0=a0... rts ; Done with handler... * ******************************************************************************* * HandlerInfo: ds.b IS_SIZE ; The handler structure... EndOfCode: CodeSize EQU EndOfCode-StartOfCode HandlerOffset: EQU HandlerInfo-StartOfCode * ******************************************************************************* * * The data section... * inputName dc.b 'input.device',0 * ******************************************************************************* * * And, with that we come to the end of another full-length feature staring * that wonderful MC680x0 and the Amiga system. Join us again next time * for more Wonderful World of Amiga... Until then, keep boinging... * end