sys7.1-doc-wip/DeclData/DeclVideo/DBLite/DBLiteDriver.a

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;
; File: DBLite.a
;
; Contains: This file contains the video driver for use by the Macintosh
; OS for the GSC hardware (PowerBooks 160, 180, Duo 210, Duo 230).
;
; Written by: Mike Puckett
;
; Copyright: © 1991-1993 by Apple Computer, Inc. All rights reserved.
;
; Change History (most recent first):
;
; <SM5> 12/13/93 PN Roll in KAOs and Horror changes to support Malcom and AJ
; machines
; <SM4> 11/5/92 SWC Changed VideoEqu.a->Video.a and ShutdownEqu.a->Shutdown.a.
; <SM3> 11/2/92 kc Don't include SonicEqu.a.
; <SM7> 10/22/92 CSS Fix short branch to regular branch.
; <1> 10/6/92 GDW New location for ROMLink tool.
; <SM5> 09-03-92 jmp Clean-up some mistakes in <SM4>s check-in comments.
; <SM4> 09-03-92 jmp (SWC,H18) DBLite once again uses a Time Manager task instead of
; the GSC interrupt because we were seeing cursor breakup at the
; top of the screen.
; (SWC,H17) Rolled the refresh/skew table lookup code back in (it
; seems to have been deleted sometime between <H10> and now...)
; Hopefully now using the final GSC refresh/skew values for
; DBLite.
; (jmp,H16) Corrected .s vs. non-.s branches.
; (djw,H15) Removed DBLiteGetVidAttributes call to avoid adding
; new Apple "required" calls to video drivers.
; (HJR,H14) Removed control LowPwrSelect since it may cause too
; much confusion between dimming and sleep.
; (HJR,H13) Added new control call, LowPwrSelect for dimming. Also
; fixed a bug in SetDepth whether there was improper register useage.
; (djw,H12) Added DBLiteGetVidAttributes status call with a
; negative csCode (-16384). Fix bug in Control and status common
; dispatcher dealing with the extended table. Fixed bug in
; DBLiteBlankScreen control routine.
; (HJR,H11) Added DBLiteBlankScreen routine to clear the screen.
; Added a 33 millisecond delay in SetDepth to help with a DSack
; problem. Modifies DBLiteCSCommon to handle additional Cntrl and
; Status calls. In DBLiteVidClose, turn off the backlight driver
; and blank the screen. In DBLiteVidOpen, open the backlight
; driver.
; (SWC,H10) Changed bit depth code to change both the skew and
; refresh rate together since the two values are interdependent.
; <SM3> 5/16/92 kc Roll in Horror Changes. Comments follow:
; <H9> 4/16/92 SWC Added adjustment of the GSC's skew register based on the bit
; depth.
; <H8> 3/12/92 SWC Save D0 across the StripAddress in the control/status code so
; that we can return the correct error code. Fixed a bug in
; GetEntries that always caused us to return the 1-bit entry
; table.
; <H7> 2/13/92 HJR Fix header in <H6>.
; <H6> 2/13/92 HJR Added Time Manager pseudo panel interrupts to Niagra machines
; since it does not support real interrupts from the GSC.
; <H5> 1/16/92 SWC Did a bit more driver cleanup.
; <H4> 1/13/92 SWC Removed the GrayScreen call in SetDepth since we ended up with a
; gray screen instead of "real stuff" when exiting Macsbug.
; Replace the Time Manager pseudo panel interrupts with the real
; thing from the GSC. Cleaned up the driver code a bit.
; <H3> 12/10/91 HJR Fixed some minor table lookup bugs.
; <H2> 11/26/91 jmp Added VERY preliminary support for the GSC.
; <2> 3/31/92 JSM Rolled this file into Reality.
; <2> 5/22/91 jmp Code Review changes: For consistency, did a StripAddress on
; VidOpens copy of the privates; eliminated the redundant clears
; and checks for the the driver copy of the fixed-entry clut; and
; replaced #0s with #noErrs where appropriate.
; <1> 5/15/91 jmp first checked in
;
STRING C
PRINT OFF
LOAD 'StandardEqu.d'
INCLUDE 'DockingEqu.a'
INCLUDE 'EgretEqu.a'
INCLUDE 'GestaltEqu.a'
INCLUDE 'GestaltPrivateEqu.a'
INCLUDE 'HardwarePrivateEqu.a'
INCLUDE 'IOPrimitiveEqu.a'
INCLUDE 'PowerPrivEqu.a'
INCLUDE 'ROMEqu.a'
INCLUDE 'Video.a'
INCLUDE 'SlotMgrEqu.a'
INCLUDE 'ShutDown.a'
; INCLUDE 'SonicEqu.a'
INCLUDE 'UniversalEqu.a'
INCLUDE 'DepVideoEqu.a'
PRINT ON
SEG '_sDBLiteDriver'
BLANKS ON
STRING ASIS
MACHINE MC68020
kDBLiteVBLTime EQU -16626 ; 60.14742 Hz using the microsecond timer.
; This is device storage which is stored in the dCtlStorage field of the AuxDCE.
DBLiteVidPrivates RECORD 0
saveBaseAddr DS.L 1 ; the screen base address
saveGSCAddr DS.L 1 ; the VDAC (GSC) base address
saveFixedCLUT DS.L 1 ; pointer to fixed-entry CLUT
saveNumFixedEntries DS.W 1 ; number of entries in fixed CLUT (zero based)
GFlags DS.W 1 ; flags word (hi-order byte, actually)
saveMode DS.W 1 ; the current mode setting
TTask DS.B tmXQSize ; extended time manager task block
IntDisableFlag DS.W 1 ; this word is non-zero when the VBL interrupt
DBLiteVidPrivSize EQU *
ENDR
LDBLiteDriver MAIN EXPORT
;-------------------------------------------------------------------
; Video Driver Header
;-------------------------------------------------------------------
;
DBLiteDrvr DC.W $4C00 ; ctl,status,needsLock
DC.W 0,0,0 ; not an ornament
; Entry point offset table
DC.W DBLiteVidOpen-DBLiteDrvr ; open routine
DC.W DBLiteDrvr-DBLiteDrvr ; no prime
DC.W DBLiteVidCtl-DBLiteDrvr ; control
DC.W DBLiteVidStatus-DBLiteDrvr ; status
DC.W DBLiteVidClose-DBLiteDrvr ; close
STRING Pascal
DBLiteVidTitle DC.B '.Display_Video_Apple_GSC'
ALIGN 2 ; make sure we're word aligned
DC.W CurGSCDrvrVersion ; version
STRING ASIS
;
; According to CARDS & DRIVERS, video drivers are supposed to shut off
; video at close time “to avoid the persistence of the desktop
; during reboots.” Since we cant really turn DBlites video off,
; we must simulate it by turning off the backlighting and writing
; white (because its an LCD screen) to the frame buffer. Also,
; because the video driver might be closed and then re-opened
; prior to a reboot (AUX?), we must always re-open the backlight
; driver in the video drivers open routine. And, for this reason,
; when we close the backlight driver, we do NOT remove its DCE,
; and do we dont dispose of the driver. NOTE: On the first
; time thru (i.e., after startup or restart), the Backlight driver
; will not have been installed yet, so our attempting to open it
; in our open routine will fail, which is okay. This may change
; in the future.
;
String Pascal
DBLiteBackLite Dc.b '.Backlight' ; Name of Backlight Driver for DBLite.
String Asis
Align 2
;
; The following table is used by the GrayScreen routine for drawing the 50% gray pattern
; at the appropriate bit depth. The “number of rows” entry is for future expansion --
; that is, if we ever need to distinguish between 640x400 vs. 640x480 panels.
;
DBGrayTblRec Record 0
grayTblPat Ds.l 1 ; The bit-pattern to use at this depth.
grayTblRow Ds.w 1 ; The (number of longwords)-1 at this depth.
grayTblCol Ds.w 1 ; The (number of rows)-1 at this depth.
DBGrayTblSize Equ *
Endr
DBLiteGrayTbl
Dc.l OneBitGray ; 1bpp
Dc.w (OBMLCDRB/4)-1,defmBounds_BLCD-1 ;
Dc.l TwoBitGray ; 2bpp
Dc.w (TBMLCDRB/4)-1,defmBounds_BLCD-1 ;
Dc.l FourBitGray ; 4bpp
Dc.w (FBMLCDRB/4)-1,defmBounds_BLCD-1 ; <H3>
;
; In order to save the state of the GSC across the sleep/wake transition, we need
; to write out the registers themselves.
;
GSCRegs Dcb.b 10,0 ; The GSC reg save/restore area.
WITH DBLiteVidPrivates,VDPageInfo,DBGrayTblRec
**********************************************************************
*
* DBLiteVidOpen allocates private storage for the device in the AuxDCE and locks
* it down for perpetuity. Also, install the simulated interrupt handler and
* start it going.
*
* Entry: A0 = param block pointer
* A1 = AuxDCE pointer
*
* Locals: A3 = pointer to private storage
*
**********************************************************************
DBLiteVidOpen
;
; Allocate private storage (since block is CLEAR, GFlags are zeroed) and get
; a pointer to it in A3.
;
MOVEQ #DBLiteVidPrivSize,D0 ; get size of parameters
_ResrvMem ,SYS ; make room as low as possible
MOVEQ #DBLiteVidPrivSize,D0 ; get size of parameters
_NewHandle ,SYS,CLEAR ; get some memory for private storage
BNE.S @OpError1 ; => return an error in open
MOVE.L A0,dCtlStorage(A1) ; save returned handle in AuxDCE
_HLock ; and lock it down forever (this includes a Time Mgr QElem)
MOVE.L (A0),D0 ; get a 32-bit clean pointer…
_StripAddress ; …to our privates into A3
MOVEA.L D0,A3
;
; Remember the VDAC (GSC) and framebuffer base addresses since theyre fairly painful to look up.
;
With ProductInfo,DecoderInfo,VideoInfo
Move.l UnivInfoPtr,A0 ; Get a pointer to the universal data.
Move.l A0,-(Sp) ; Save it temporarily on the stack.
Adda.l DecoderInfoPtr(A0),A0 ; Point to the base address table.
Move.l VDACAddr(A0),saveGSCAddr(A3) ; Save pointer to GSC (“VDAC”).
Move.l (Sp)+,A0 ; Point back at the universal data.
Adda.l VideoInfoPtr(A0),A0 ; Point to the VideoInfo record. <H3>
Move.l VRAMLogAddr32(A0),saveBaseAddr(A3) ; Save pointer to the framebuffer base.
Endwith
; The Niagra board does not support a real interrupt for doing VBLs,
; so we simulate them by using a Time Manager task that is set at 60.14742 Hz.
; While the DBLite board -does- support GSC interrupts, we found we had problems
; with cursor breakup at the top of the screen, so we now use a Time Manager
; task as well.
LEA TimeManagerIH,A0 ; get a pointer to the interrupt simulation timer task code
MOVE.L A0,tmAddr+TTask(A3) ; put it in the time task
LEA TTask(A3),A0 ; get a pointer to the timer queue element
Move.l #'eada',(A0) ; Put in the magic signature to prevent VM from deferring us.
_InsXTime ; Install the task (fixed frequency). <H6>
BSR DBLiteEnableVGuts ; do it
BNE.S @OpError2
; Attempt to re-open the Backlight driver because it might have been closed <H11>
; if someone (AUX?) closed us and then tried to reopen us prior to |
; rebooting. Currently, this call will fail the first time thru v
; because video is installed before backlighting on boot.
;
Moveq #(ioQElSize/2)-1,D0 ; Set up init-loop counter.
@ClrBlk Clr.w -(Sp) ; Allocate and clear param block.
DBra D0,@ClrBlk ; Do it one word at a time.
Lea DBLiteBackLite,A0 ; Point to Backlight driver name.
Move.l A0,ioFileName(Sp) ; Load it into param block.
Movea.l Sp,A0 ; Get param block pointer into A0.
_Open ; Open driver to get the refNum.
Adda.w #ioQElSize,Sp ; Restore the stack.
; All done! <H11>
;
MOVEQ #noErr,D0 ; no error
RTS
@OpError2 MOVE.L dCtlStorage(A1),A0 ; get the private storage back
_DisposHandle ; release the driver private storage
@OpError1 MOVEQ #OpenErr,D0 ; say can't open driver
RTS
**********************************************************************
*
* VideoClose releases the device's private storage and removes the
* interrupt handler.
*
*
* Entry: A0 = param block pointer
* A1 = AuxDCE pointer
*
* Other: A2 = temporary AuxDCE pointer copy
*
**********************************************************************
DBLiteVidClose
MOVE.L dCtlStorage(A1),A3 ; A3 <- Ptr to private storage
MOVE.L (A3),D0 ;
_StripAddress ;
MOVE.L D0,A3 ;
; Close the Backlight driver.
;
Moveq #(ioQElSize/2)-1,D0 ; Set up init-loop counter.
@ClrBlk Clr.w -(Sp) ; Allocate and clear param block.
DBra D0,@ClrBlk ; Do it one word at a time.
Lea DBLiteBackLite,A0 ; Point to Backlight driver name.
Move.l A0,ioFileName(Sp) ; Load it into param block.
Movea.l Sp,A0 ; Get param block pointer into A0.
_Open ; Open driver to get the refNum.
Bne.s @SkipClose ; If open fails, dont try to close it.
_Close ; Otherwise, close it.
@SkipClose
Adda.w #ioQElSize,Sp ; Restore the stack.
; Blank the screen.
;
Movea.l saveGSCAddr(A3),A0 ; Point to the GSC base address.
Bclr #GSCBlankCtl,GSCGrayScale(A0) ; Blank video.
; Disable cursor interrupts.
;
MOVE.W #-1,IntDisableFlag(A3) ; set this word to “disable” interrupts
LEA TTask(A3),A0 ; get the time manager task block
_RmvTime ; remove this element from the queue
; Disable fixed-clut table if necessary.
;
Move.l saveFixedCLUT(A3),D0 ; If we havent loaded our fixed-entry CLUT,
Beq.s @EndFixed ; then just go on.
Move.l D0,A0 ; Otherwise, dispose of it.
_DisposPtr
@EndFixed
; Dispose of private storage.
;
MOVE.L dCtlStorage(A1),A0 ; Dispose of the private storage
_DisposHandle ;
MOVEQ #noErr,D0 ; no error
RTS ; and return
**********************************************************************
*
* Video Driver Control Call Handler. There are ten calls:
*
* (0) Reset (VAR mode, page: INTEGER; VAR BaseAddr: Ptr);
* (1) KillIO
* (2) SetMode(mode, page: INTEGER; VAR BaseAddr: Ptr);
* (3) SetEntries ( Table: Ptr; Start,Count : integer );
* (4) SetGamma ( Table : Ptr );
* (5) GrayPage (page);
* (6) SetGray (csMode = 0 for color, 1 for gray)
* (7) SetInterrupt ( csMode = 0 for enable, 1 for disable)
* (8) DirectSetEntries (not implemented)
* (9) SetDefaultMode
*
* Entry: A0 = param block pointer
* A1 = AuxDCE pointer
* Uses: A2 = ptr to cs parameters (ie. A2 <- csParam(A0))
* A3 = scratch (doesn't need to be preserved)
* A4 = scratch (must be preserved)
* D0-D3 = scratch (don't need to be preserved)
*
* Exit: D0 = error code
*
**********************************************************************
DBLiteVidCtl
LEA @ctlJumpTbl-2,A4 ; point to the Control dispatch table
MOVEQ #controlErr,D0 ; default error if it's a bad opcode
BRA.S DBLiteCSCommon ; jump to common Control/Status code
DC.W (@StdctlJumpTblEnd-2-@ctlJumpTbl)/2; highest control call we support
@ctlJumpTbl DC.W DBLiteVidReset-@ctlJumpTbl ; $00 => VidReset
DC.W DBLiteKillIO-@ctlJumpTbl ; $01 => KillIO
DC.W DBLiteSetVidMode-@ctlJumpTbl ; $02 => SetVidMode
DC.W DBLiteSetEntries-@ctlJumpTbl ; $03 => SetEntries ••• MacsBug Hack •••
DC.W DBLiteCSDone-@ctlJumpTbl ; $04 => SetGamma (not needed)
DC.W DBLiteGrayPage-@ctlJumpTbl ; $05 => GrayPage
DC.W DBLiteCSDone-@ctlJumpTbl ; $06 => SetGray (not needed)
DC.W DBLiteSetInterrupt-@ctlJumpTbl ; $07 => SetInterrupt
* DC.W DBLiteCSDone-@ctlJumpTbl ; $08 => DirectSetEntries (not needed)
* DC.W DBLiteCSDone-@ctlJumpTbl ; $09 => SetDefaultMode (not needed)
@StdctlJumpTblEnd
DC.W cscSleepWake,DBLiteSetSleepWake-@ctlJumpTbl ; SleepWake
DC.W 0 ; end-of-table marker
**********************************************************************
*
* Video Driver Status Call Handler. Right now there are ten calls:
*
* (0) Error
* (1) Error
* (2) GetMode
* (3) GetEntries
* (4) GetPage
* (5) GetPageBase
* (6) GetGray
* (7) GetInterrupt
* (8) GetGamma
* (9) GetDefaultMode
*
* Entry: A0 = param block
* A1 = AuxDCE pointer
* Uses: A2 = cs parameters
* A3 = pointer to private storage
* D0-D3 = scratch (don't need to be preserved)
*
* Exit: D0 = error code
*
**********************************************************************
DBLiteVidStatus
LEA @statJmpTbl-2,A4 ; point to the Status dispatch table
MOVEQ #statusErr,D0 ; default error if it's a bad opcode
BRA.S DBLiteCSCommon
DC.W (@StdstatJmpTblEnd-2-@statJmpTbl)/2; highest status call we support
@statJmpTbl DC.W DBLiteCSDone-@statJmpTbl ; $00 => Error
DC.W DBLiteCSDone-@statJmpTbl ; $01 => Error
DC.W DBLiteGetMode-@statJmpTbl ; $02 => GetMode
DC.W DBLiteGetEntries-@statJmpTbl ; $03 => GetEntries
DC.W DBLiteGetPage-@statJmpTbl ; $04 => GetPage
DC.W DBLiteGetPageBase-@statJmpTbl ; $05 => GetPageBase
DC.W DBLiteGetGray-@statJmpTbl ; $06 => GetGray
DC.W DBLiteGetInterrupt-@statJmpTbl ; $07 => GetInterrupt
DC.W DBLiteCSDone-@statJmpTbl ; $08 => GetGamma (not needed)
DC.W DBLiteGetDefaultMode-@statJmpTbl; $09 => GetDefaultMode
@StdstatJmpTblEnd
DC.W cscSleepWake,DBLiteGetSleepWake-@statJmpTbl ; SleepWake
DC.W 0 ; end-of-table marker
DBLiteCSCommon
MOVE.W csCode(A0),D1 ; get the opcode
MOVE.W (A4)+,D2 ; get size of StdTable <H11>
CMP.W D2,D1 ; IF inStdRange THEN |
BLS.S @DoCall ; use StdTable and Do CntrCall v
MOVE.W D2,D3 ; Get end of StdTable
SUBQ.W #1,D3 ; adjust for first element in extended tbl <H12>
@Loop ADDQ.W #2,D3 ; Increment counter
MOVE.W (A4,D3.W*2),D2 ; Get routine code
BEQ.S @BadCode ; End of list Reached… Bad Code
CMP.W D2,D1 ; IF csCode == TableCode THEN
BNE.S @Loop ; Use Extended Range
MOVE.W D3,D1 ; Use new index
ADDQ.W #1,D1 ; increment it for proper table entry <H11>
@DoCall MOVEA.L csParam(A0),A2 ; point to parameters
MOVE.L D0,-(SP) ; save the error code
MOVEA.L dCtlStorage(A1),A3 ; point to our storage
MOVE.L (A3),D0 ; and de-reference the handle
_StripAddress ; make sure the pointer is 32-bit clean
MOVEA.L D0,A3 ; save the 32-bit clean pointer
MOVE.L (SP)+,D0 ; restore error code
MOVEM.L A0-A3,-(SP) ; save exit registers
MOVE.W (A4,D1.W*2),D1 ; get the relative offset to the routine
JSR 0(A4,D1.W) ; Go do it
MOVEM.L (SP)+,A0-A3 ; restore exit registers.
Move.w csCode(A0),D1 ; Get the routine selector.
Cmpi.w #cscSetMode,D1 ; If its the SetMode routine,
Beq.s @EndBlnkChk ; then dont unblank the display.
Cmpi.w #cscSleepWake,D1 ; If its the Sleep/Wake routine,
Beq.s @EndBlnkChk ; then dont unblank the display.
Bclr #InBlanking,GFlags(A3) ; Say that we want the screen unblanked now.
Bsr DBLiteBlankCtl ; And do it.
@EndBlnkChk
@BadCode BTST #NoQueueBit,ioTrap(A0) ; no queue bit set?
BNE.S DBLiteCSDone ; -> yes, it's an immediate call, so just exit
MOVE.L jIODone,-(SP) ; otherwise exit thru IODone
DBLiteCSDone
RTS
**********************************************************************
*
* Control Routines
*
**********************************************************************
DBLiteVidReset
;---------------------------------------------------------------------
;
; Reset the card to its default
;
;---------------------------------------------------------------------
MOVE.W #FirstVidMode,csMode(A2) ; return default mode
MOVE.W #FirstVidMode,saveMode(A3) ; remember FirstVidMode as the requested mode
MOVEQ #0,D1 ; get default depth in D1 (#firstVidMode-#firstVidMode)
MOVEQ #0,D0 ; get page in D0
MOVE.W D0,csPage(A2) ; return the page
BSR DBLiteSetDepth ; set the depth from D1 (also grays the screen)
MOVE.L saveBaseAddr(A3),csBaseAddr(A2) ; return the base address
DBLiteKillIO
MOVEQ #NoErr,D0
RTS
DBLiteSetVidMode
;---------------------------------------------------------------------
;
; Set the card to the specified mode and page. Only page zero is
; possible, so we need to check that the request was OK.
;
; If the card is already set to the specified mode, then do nothing.
;
;---------------------------------------------------------------------
Move.w csMode(A2),D1 ; D1 = mode.
BSR DBLiteChkMode ; check mode and convert
BHI.S @BadParam ; => not a valid mode
Tst.w csPage(A2) ; only page zero is valid
BNE.S @BadParam ; => not a valid page
; Only set if the mode has changed.
Move.w csMode(A2),D2 ; get the mode spID (D1 has the zero-base mode)
Cmp.w saveMode(A3),D2 ; has the mode changed?
Beq.s @ModeOK ; if not, just return the baseAddr
; Remember the newly requested mode, and switch depths with our utility.
Bset #InBlanking,GFlags(A3) ; Say that we want the screen to be blanked.
Bsr DBLiteBlankCtl ; And go do it.
Move.w D2,saveMode(A3) ; remember requested mode
Bsr DBLiteSetDepth ; switch depths
Move.l saveFixedCLUT(A3),D0 ; If weve havent loaded the fixed-entry CLUT,
Beq.s @ModeOK ; just go on.
Move.l D0,A0 ; Otherwise, set up to throw it away.
_DisposPtr ; Throw it away…
Clr.l saveFixedCLUT(A3) ; …and remember that its gone.
@ModeOK Move.l saveBaseAddr(A3),csBaseAddr(A2) ; return the base address
MOVEQ #NoErr,D0
@BadParam RTS
DBLiteSetEntries
;---------------------------------------------------------------------
;
; Since DBLite has no color table, theres nothing to do here. We
; dont do this in the dispatcher above so that the BlankShading
; works with MacsBug around.
;
;---------------------------------------------------------------------
Moveq #controlErr,D0 ; Say that we dont do entries.
Rts ; And vamoose.
DBLiteSetGamma
;---------------------------------------------------------------------
;
; Since DBLite has no color table, there's no opportunity to set the
; gamma correction in this hardware. Return a bad result but
; do it up above in the control dispatcher, since it saves a few bytes.
;
;---------------------------------------------------------------------
DBLiteGrayPage
;---------------------------------------------------------------------
;
; Clear the specified page in the current mode to gray
;
; A1 = Ptr to AuxDCE
; A2 = Ptr to cs parameter record
; A3 = Ptr to private storage
;
;---------------------------------------------------------------------
Move.w saveMode(A3),D1 ; D1 = mode
Bsr DBLiteChkMode ; convert mode to depth in D1
BHI.S @BadParam ; => not a valid depth
TST.W csPage(A2) ; Is it requesting page zero?
BNE.S @BadParam ; -> nope
BSR DBLiteGrayScreen ; paint the screen gray
MOVEQ #NoErr,D0
@BadParam RTS
DBLiteSetGray
;---------------------------------------------------------------------
;
; Since DBLite has no color table, there's no opportunity to set
; luminence mapping in this hardware. Return a bad result but
; do it up above in the control dispatcher, since it saves a few bytes.
;
;---------------------------------------------------------------------
DBLiteSetInterrupt
;---------------------------------------------------------------------
;
; Enable (csMode = 0) or disable (csMode = 1) VBL interrupts
;
; As a future performance enhancement, interrupts on the card can be
; disabled or enabled from software. For instance, if the cursor is
; not on a screen, and there is nothing in the Slot Interrupt Queue
; for that device, interrupts may be disabled reducing interrupt
; overhead for the system.
;
; The slot interrupt queue element is always allocated by the Open call.
; This routine just inserts and removes it from the slot interrupt task queue.
;
; A1 = Ptr to AuxDCE
; A2 = Ptr to cs parameter record
; A3 = Ptr to private storage
;
;---------------------------------------------------------------------
Tst.b csMode(A2) ; Check to see which way were going.
Bne.s DBLiteDisableVGuts ; If non-zero, disabling.
Bra.s DBLiteEnableVGuts ; Otherwise, enabling.
DBLiteDisableVGuts
Move.w #-1,IntDisableFlag(A3) ; Remember that were disabling things.
MOVEQ #NoErr,D0
RTS
DBLiteEnableVGuts
Clr.w IntDisableFlag(A3) ; Remember that were enabling things.
MOVE.L A1,-(SP) ; jPrimeTime trashes A1
LEA TTask(A3),A0 ; get time task block in A0
MOVE.L #kDBLiteVBLTime,D0 ; delay for about 1/60th of a second
MOVE.L jPrimeTime,A1 ; point straight at the Time Manager dispatch vector
JSR (A1) ; start the delay going
MOVEA.L (SP)+,A1 ;
Moveq #NoErr,D0 ; say were okay
RTS ; return home
DBLiteSetDefaultMode
;---------------------------------------------------------------------
;
; Since DBLite has no sRsrc families, just return bad result
; but do it up above in the control dispatcher, since it saves a
; few bytes.
;
;---------------------------------------------------------------------
DBLiteSetSleepWake
;---------------------------------------------------------------------
;
; SleepWake <csCode = 134> - save or restore operating state across
; sleep/wake transition. This routine is called by the sleep or wake
; I/O Primitive code.
;
; Input: A1 = ptr to AuxDCE
; A2 = ptr to csParams
; A3 = ptr to driver globals
;
; csParams: csMode.b 0 = sleep, non-zero = wake
;
;---------------------------------------------------------------------
; Check to see if we even need to be here or not…
;
Moveq #controlErr,D0 ; Assume well fail for now.
Tst.b csMode(A2) ; If the request was to sleep, then
Beq.s @ChkSleep ; make sure its okay.
Btst #IsSleeping,GFlags(A3) ; Otherwise, if were not already awake, then
Bne.s @DoWakeup ; go do the wakeup code.
Rts ; Otherwise, somethings wrong.
@DoWakeup Bsr DBLiteRestoreState ; Go restore the state of the world.
Bsr DBLiteEnableVGuts ; Turn cursor interrupts back on.
Moveq #noErr,D0 ; And return…
Rts ; …happy.
@ChkSleep Btst #IsSleeping,GFlags(A3) ; If were not already sleeping, then
Beq.s @DoSleep ; go do the sleep code.
Rts ; Otherwise, somethings wrong.
@DoSleep Bsr DBLiteDisableVGuts ; Turn off cursor interrupts for good measure.
Bsr DBLiteSaveState ; Save the state of the world.
Moveq #noErr,D0 ; And return…
Rts ; …happy.
**********************************************************************
*
* Status Routines
*
**********************************************************************
DBLiteGetMode
;---------------------------------------------------------------------
;
; Return the current mode
;
; Inputs : A2 = pointer to csParams
; A3 = pointer to private storage
;
;---------------------------------------------------------------------
Tst.w saveMode(A3) ; If saveMode has been set,
Bne.s @ModeOK ; then just go on.
Move.w #FirstVidMode,saveMode(A3) ; Otherwise, just set it to 1bpp (non-GSC case).
@ModeOK MOVE.W saveMode(A3),csMode(A2) ; return the mode
CLR.W csPage(A2) ; return the page number
MOVE.L saveBaseAddr(A3),csBaseAddr(A2) ; and the base address
MOVEQ #NoErr,D0
RTS
DBLiteGetEntries
;---------------------------------------------------------------------
;
; Fake the current contents of the CLUT. There isn't really a clut around,
; but that's no reason not to return a reasonable looking response
;
; Inputs: A1 = pointer to AuxDCE
; A2 = pointer to csParams
; A3 = pointer to privates
;
; For DBLite the color table is fixed. So, well always return good values
; as long as there is a reasonable looking color table around.
;
; Idea: If were in indexed mode, well cycle thru the input
; table. While doing this, well ignore all entries
; whose value fields are out of range. For entries
; whose value field are in range, well return the
; appropriate rgb fields.
;
; If were in sequential mode, we just need to write out
; the number of entries we know about.
;
;---------------------------------------------------------------------
Move.l csTable(A2),D1 ; If we were handed a nil table pointer,
BEQ @GEDone ; then just exit
MOVE.L D1,D0
_StripAddress ; Otherwise, make table pointer 32-bit clean
MOVE.L D0,D3 ; and save it for later
Tst.l saveFixedClut(A3) ; If weve already loaded the CLUT for this depth,
Bne.s @GEStart ; then just go on.
With SpBlock
LEA -spBlockSize(SP),SP ; Make an SpBlock on the stack and
Move.l Sp,A0 ; get a pointer to it into A0.
Clr.b spSlot(A0) ; Were always in slot 0.
Move.b dCtlSlotID(A1),spID(A0) ; Get the spID of the video sRsrc.
Clr.b spExtDev(A0) ;
_sRsrcInfo ; Try to get the spsPointer.
Bne.s @GESlotErr ; If failed, then quit.
Move.w saveMode(A3),D0 ; If the current mode has been set, <H8>
Bne.s @ModeOK ; then go on.
Move.b #FirstVidMode,D0 ; Otherwise, assume 1bpp (non-GSC case).
@ModeOK Move.b D0,spID(A0) ; Look for our mode entry.
_sFindStruct ; If its not there,
Bne.s @GESlotErr ; then quit.
Move.b #mTable,spID(A0) ; Get our fixed-entry CLUT.
_sGetBlock ; If its not there,
Bne.s @GESlotErr ; then quit.
Move.l spResult(A0),A0 ; Get a pointer to our fixed-entry CLUT.
Move.w ctSize(A0),saveNumFixedEntries(A3) ; Save the number of entries.
Lea ctTable(A0),A0 ; Get a ptr to the table, and
Move.l A0,saveFixedCLUT(A3) ; save it.
@GESlotErr LEA spBlockSize(SP),SP ; clean up the stack
TST.W D0 ; was there an error?
BNE.S @GEDone ; -> yes, bail
EndWith
; Calculate the index range…
;
@GEStart MOVEQ #statusErr,D0
Move.l D3,A0 ; get pointer to input table.
Move.w saveNumFixedEntries(A3),D3 ; Get number of entries to check against.
Move.w csCount(A2),D4 ; Get the number of entries to change,
Bmi @GEDone ; and hike if its out of range.
Cmp.w D3,D4 ; If D4-D3 > 0 (count - range > 0),
Bhi @GEDone ; then hike.
Tst.w csStart(A2) ; If were doing indexed entries (-1),
Bmi.s @skipStartChk ; then just go on.
Add.w csStart(A2),D4 ; Adjust count for starting position.
Cmp.w D3,D4 ; If D4-D3 > 0 (count - range > 0),
Bhi @GEDone ; then hike.
@skipStartChk
Move.w csCount(A2),D2 ; Remember the csCount.
Cmpi.w #indexEntries,csStart(A2) ; If table accesses are to be indexed,
Beq.s @GECom ; then go on.
; The following code is BAD, BAD, BAD! We should build our own table here so
; as to NOT mess up the users data. But all the previous Apple video drivers
; have done the same thing, so well continue the trend for now.
Move.w D2,D1 ; Get count.
@TableLoop Move.w D4,value(A0,D1*colorSpecSize) ; Write the index into the table.
Subq #1,D4 ; Decrement index.
Dbra D1,@TableLoop
@GECom
@Repeat Move.w value(A0),D1 ; Get the NEXT table position into D1.
Cmp.w D3,D1 ; If this position is out of range,
Bhi.s @Until ; then go on.
Movea.l saveFixedCLUT(A3),A1 ; Point to start of fixed CLUT.
Lea (A1,D1*colorSpecSize),A1 ; Index into right entry.
Move.w rgb+red(A1),rgb+red(A0) ; Copy red,
Move.w rgb+green(A1),rgb+green(A0) ; green,
Move.w rgb+blue(A1),rgb+blue(A0) ; blue.
@Until Addq #colorSpecSize,A0 ; Point to next entry in input ColorTable.
Dbra D2,@Repeat
MOVEQ #NoErr,D0 ; success
@GEDone RTS
DBLiteGetPage
;---------------------------------------------------------------------
;
; Return the number of pages in the specified mode.
;
;---------------------------------------------------------------------
Move.w csMode(A2),D1 ; get the mode
BSR.S DBLiteChkMode ; is this mode OK?
BHI.S @BadMode ; => not a valid mode
MOVE.W #defPagesLCD,csPage(A2) ; return page count
MOVEQ #NoErr,D0
@BadMode RTS
DBLiteGetPageBase
;---------------------------------------------------------------------
;
; Return the base address for the specified page in the current mode
;
;---------------------------------------------------------------------
TST.W csPage(A2) ; are we returning page zero info?
BNE.S @BadPage ; => no, just return
MOVE.L saveBaseAddr(A3),csBaseAddr(A2) ; return the base address
MOVEQ #NoErr,D0
@BadPage RTS
DBLiteGetGray
;---------------------------------------------------------------------
;
; No CLUT, but this routine always returns a non-zero value (1)
; to indicate that gray mode is on (forever).
;
;---------------------------------------------------------------------
Move.b #1,csMode(A2) ; Say that gray mode is on.
Moveq #noErr,D0
Rts
DBLiteGetInterrupt
;---------------------------------------------------------------------
;
; Return a boolean in csMode, set true if VBL interrupts are disabled
;
;---------------------------------------------------------------------
Tst.w IntDisableFlag(A3) ; If the interrupt state is enabled,
Beq.s @IsOn ; then say so.
Move.b #1,csMode(A2) ; Otherwise, return disabled.
Bra.s @Done ; And leave.
@IsOn Clr.b csMode(A2) ; Return enabled state.
@Done Moveq #noErr,D0 ; Return noErr.
Rts ; And leave.
DBLiteGetGamma
;---------------------------------------------------------------------
;
; No CLUT, so this routine returns an status error. It's implemented
; in the Status dispatch table above.
;
;---------------------------------------------------------------------
DBLiteGetDefaultMode
;---------------------------------------------------------------------
;
; Read the card default mode from slot pRAM.
;
; A1 = Ptr to AuxDCE
; A2 = Ptr to cs parameter record
; A3 = Ptr to private storage
;
;---------------------------------------------------------------------
; For most video drivers, we look in pRAM to see what the last
; configuration set was. However, for DBLite, we just need
; to return our current functional sRsrc ID (i.e., there are
; no family modes here).
MOVE.B dCtlSlotID(A1),csMode(A2) ; return the result
MOVEQ #NoErr,D0
RTS
DBLiteGetSleepWake
;---------------------------------------------------------------------
;
; GetSleepWake
;
; Reads the default family mode from slot pRAM.
;
; Input: A1 = ptr to AuxDCE
; A2 = ptr to csParams
; A3 = ptr to driver globals
;
; csParams: csMode.b <- 0 = sleep, non-zero = wake
;
;---------------------------------------------------------------------
Btst #IsSleeping,GFlags(A3) ; Test the sleep/wake flag.
Seq csMode(A2) ; Return result.
Moveq #noErr,D0 ; Vamoose.
Rts
;=====================================================================
;
; Utilities
;
;=====================================================================
DBLiteChkMode
;---------------------------------------------------------------------
;
; ChkMode
;
; Verifies the requested mode is legal. Converts spID in D1 into
; zero-based mode number since lots of people want it that way.
;
; <-> D1: Mode
;
; Returns BHI if mode is invalid.
;
SUBI.W #FirstVidMode,D1 ; make mode zero-based.
CMPI.W #ThirdVidMode-FirstVidMode,D1 ; valid mode values are 0-2
RTS
DBLiteSetDepth
;---------------------------------------------------------------------
;
; SetDepth
;
; Set the requested frame buffer depth.
;
; D1 = spID of the depth - FirstVidMode
; A1 = AuxDCEPtr
; A2 = param block pointer
; A3 = dCtlStorage pointer
;
; All registers are preserved.
Movem.l D0/D2/A0,-(Sp) ; Save work registers.
; Raise the interrupt level to level 2 so that VBL and timer tasks will not run
Move.w SR,-(Sp) ; Get the status register on stack. <H11>
Moveq #7,D0 ; Get mask into D0. |
And.b (SP),D0 ; Get the interrupt level. v
Subq.b #2,D0 ;
Bge.s @OK ; If ≥, then don't change.
Ori.w #$0200,SR ; Raise above level-2.
Andi.w #$FAFF,SR ; Make it level-2 <H11>
@OK
Move.l saveGSCAddr(A3),A0 ; Get the GSC base address.
Move.b GSCGrayScale(A0),D0 ; Get the current value. <H13>
; The GSC has a problem where DSACK may not happen after the last register access. If <H11>
; we delay 2 frame times (approx. 32ms), then the GSC corrects itself, otherwise we will |
; get a bus timeout bus error waiting for DSACK. This problem is particularly annoying v
; because the GSC may decide to give DSACK at sometime later which would really screw us up.
Moveq #33,D2 ; Initialize loop for 33 milliseconds
@DelayLoop Swap D2 ; get low word for millisecond delay
Move.w TimeDbra,D2 ; how many spins???
@mSecDelay Dbra D2,@mSecDelay ; Delay 1 millisecond
Swap D2 ; Get out loop counter
Dbra D2,@DelayLoop ; spin <H11>
Bfins D1,D0{GSCLevelBits,GSCLevelWidth} ; Switch depths.
Move.b D0,GSCGrayScale(A0) ;
MOVEQ #7,D2 ; mask off the display ID, <H10>
AND.B GSCPanelID(A0),D2 ; <H10>
Cmpi.b #5,D2 ; If this isnt the Dart FSTN panel,
Bne.s @NotDartFSTN ; then just go on.
Move.b @polyAdj(D1),GSCPolyAdj(A0) ; Otherwise, set the m and n values.
Bra.s @NotTFT ; Skip TFT code.
@NotDartFSTN
Cmpi.b #1,D2 ; If this isnt the TFT display,
Bne.s @NotTFT ; then just go on.
Move.b #$0B,GSCDiag2(A0) ; Invert VRAM data.
Clr.b GSCPanelAdj(A0) ; Invert LCD.
@NotTFT
MULU #3,D2 ; multiply panel ID by 3 to use as a table index, <H10>
ADD.W D1,D2 ; and add in the bit depth <H10>
MOVE.B @refreshReg(D2),GSCRefreshRate(A0) ; adjust the display refresh rate <H10>
MOVE.B @skewReg(D2),GSCPanelSkew(A0) ; and the panel skew <H10>
Move.w (Sp)+,SR ; restore interrupt level
Movem.l (Sp)+,D0/D2/A0 ; Restore work registers.
Rts
; values for the refresh register based on the display mode
;
; 1-bit 2-bit 4-bit
@refreshReg DC.B 5, 3, 3 ; ID=0: TFT 1-bit <H10>
DC.B 5, 3, 3 ; ID=1: TFT 3-bit <H10>
DC.B 5, 3, 3 ; ID=2: TFT 4-bit <H10>
DC.B 5, 3, 3 ; ID=3: TFT (unassigned) <H10>
DC.B 5, 3, 3 ; ID=4: STN (unassigned) <H10>
DC.B 5, 3, 3 ; ID=5: STN - Tim <H10>
DC.B 5, 3, 3 ; ID=6: STN - DBLite <H10>
DC.B 5, 3, 3 ; ID=7: no display <H10>
; values for the skew register based on the display mode
;
; 1-bit 2-bit 4-bit
@skewReg DC.B 160, 64, 64 ; ID=0: TFT 1-bit (60Hz, 87Hz, 87Hz) <H10>
DC.B 240, 240, 240 ; ID=1: TFT 3-bit (70Hz, 70Hz, 70Hz) <H20>
DC.B 255, 128, 64 ; ID=2: TFT 4-bit (68Hz, 87Hz, 87Hz) <H10>
DC.B 255, 128, 64 ; ID=3: TFT (unassigned) (60Hz, 87Hz, 87Hz) <H10>
DC.B 160, 64, 64 ; ID=4: STN (unassigned) (60Hz, 87Hz, 87Hz) <H10>
DC.B 161, 65, 4 ; ID=5: STN - Tim (??Hz, ??Hz, ??Hz) <H20>
DC.B 156, 64, 3 ; ID=6: STN - DBLite (62Hz, 87Hz, 120Hz) <H17>
DC.B 160, 64, 64 ; ID=7: no display <H10>
; values for the m&n polyadj register based on the display mode
;
@polyAdj Dc.b 99, 130, 99 ; ID=5: STN - TIM <H20>
DC.B 00 ;padding ??? PN
DBLiteGrayScreen
;---------------------------------------------------------------------
;
; Fill the screen with a 50% dithered gray pattern.
;
; D1 = spID of screen depth - FirstVidMode
; A3 = driver private storage
;
; All registers are preserved.
;
MOVEM.L D0/D2/D3/A0-A1,-(SP) ; save work registers
Moveq #true32b,D0 ; Set up to flip into 32-bit mode.
_SwapMMUMode ; Flip.
Move.b D0,-(Sp) ; Save previous mode.
Lea DBLiteGrayTbl,A0 ; Point to the table of graying data,
Lea (A0,D1*DBGrayTblSize),A0; and load the right entry. <H3>
MOVE.L saveBaseAddr(A3),A1 ; Get the frame buffer base address.
MOVE.W grayTblCol(A0),D0 ; Get the number of rows to do.
Move.l grayTblPat(A0),D3 ; Get the bit-pattern.
@NxtRow MOVE.W grayTblRow(A0),D2 ; Get the number of longwords per row.
@NxtLong MOVE.L D3,(A1)+ ; Write gray…
DBRA D2,@NxtLong ; …for each scanline.
NOT.L D3 ; Invert pattern on the next row.
DBRA D0,@NxtRow ; Loop until done.
Move.b (Sp)+,D0 ; Restore previous addressing mode.
_SwapMMUMode
MOVEM.L (SP)+,D0/D2/D3/A0-A1 ; restore registers
RTS
DBLiteSaveState
;---------------------------------------------------------------------
;
; SaveState saves the operating state of the framebuffer controller,
; CLUT/DAC, etc…, for the sleep/wake transition.
;
; A1 = AuxDCE POINTER
; A2 = parameter block pointer
; A3 = dCtlStorage pointer
;
; Preserves all registers
;
Bset #IsSleeping,GFlags(A3) ; Remember that weve been asked to sleep.
Movem.l D0-D1/A0/A4,-(Sp) ; Save some working registers.
Movea.l saveGSCAddr(A3),A0 ; Point to the GSC base address.
Addq #GSCPanelControl,A0 ; Point to the first reg to save.
Lea GSCRegs,A4 ; Point to the register holder area.
; Save the state of the Registers…
;
MOVE.W (A0)+,(A4)+ ; panel control, panel setup
MOVEQ #$7F,D0 ; mask off the interrupt status bit
AND.B (A0)+,D0 ; in the gray scale register
MOVE.B D0,(A4)+ ; gray scale
MOVE.L (A0)+,(A4)+ ; polynomial adjust, panel adjust, ACDCLK, refresh rate
MOVE.W (A0)+,(A4)+ ; blank shade, panel skew
; Gray the VRAM…
;
Move.w saveMode(A3),D1 ; Get the current mode.
Subi.w #FirstVidMode,D1 ; Normalize it.
Bsr DBLiteGrayScreen ; Gray the screen.
Movem.l (Sp)+,D0-D1/A0/A4 ; Restore the working registers.
Rts
DBLiteRestoreState
;---------------------------------------------------------------------
;
; RestoreState restores the operating state of the framebuffer controller,
; CLUT/DAC, etc…, for the sleep/wake transition.
;
; A1 = AuxDCE POINTER
; A2 = parameter block pointer
; A3 = dCtlStorage pointer
;
; Preserves all registers
;
Movem.l D0-D1/A0/A4,-(Sp) ; Save some working registers.
Movea.l saveGSCAddr(A3),A0 ; Point to the GSC base address.
Addq #GSCPanelControl,A0 ; Point to the first reg to restore.
Lea GSCRegs,A4 ; Point to the register holder area.
; Save the state of the Registers…
;
MOVE.W (A4)+,(A0)+ ; panel control, panel setup
MOVE.B #(1<<7),(A0) ; reset the VBL interrupt pin
MOVE.B (A4)+,(A0)+ ; gray scale
MOVE.L (A4)+,(A0)+ ; polynomial adjust, panel adjust, ACDCLK, refresh rate
MOVE.W (A4)+,(A0) ; blank shade, panel skew
Movea.l saveGSCAddr(A3),A0 ; Repoint to the GSC base address.
MOVEQ #7,D1 ; Panel IDs are only 3-bits wide.
And.b GSCPanelID(A0),D1 ; Get the PanelID.
Cmpi.b #1,D1 ; If this isnt the TFT display,
Bne.s @NotTFT ; then just go on.
Move.b #$0B,GSCDiag2(A0) ; Otherwise, invert VRAM data.
Bra.s @EndRegs ;
@NotTFT
Move.b #$03,GSCDiag2(A0) ; Who knows?
@EndRegs
; Gray the VRAM…
;
Move.w saveMode(A3),D1 ; Get the current mode.
Subi.w #FirstVidMode,D1 ; Normalize it.
Bsr DBLiteGrayScreen ; Gray the screen.
Movem.l (Sp)+,D0-D1/A0/A4 ; Restore the working registers.
Bclr #IsSleeping,GFlags(A3) ; Remember that were no longer asleep.
Rts
DBLiteBlankCtl
;---------------------------------------------------------------------
;
; BlankCtl exists only because MacsBug draws the user framebuffer
; BEFORE calling SetMode when it is switching depths. Because
; we want to simulate the effect of a CLUT (by having a solid
; gray during depth switches), we use the blankshade register.
; Normally, wed couple this with a call to GrayScreen, but
; we cant because of the order in which MacsBug calls SetMode
; and redraws the screen. To get around this problem, we
; temporarily say we have a CLUT, which forces MacsBug
; to call us back (with SetEntries), and thats where we
; unblank the screen and re-assert ourselves as a Fixed
; gDevice. Ugh!
;
; A1 = AuxDCE POINTER
; A2 = parameter block pointer
; A3 = dCtlStorage pointer
;
; Preserves all registers
;
Movem.l D0-D1/A0,-(Sp) ; Save some working registers.
Move.l Devicelist,D0 ; If the DeviceList Handle is nil, then
Beq.s @Done ; we cant do anything useful here.
Movea.l saveGSCAddr(A3),A0 ; Point to the GSC base address.
Btst #InBlanking,GFlags(A3) ; If were supposed to be blanking the LCD,
Bne.s @BlankIt ; then do it.
Bset #GSCBlankCtl,GSCGrayScale(A0) ; Otherwise, unblank it.
Bra.s @EndBlank ; Move along.
@BlankIt Bclr #GSCBlankCtl,GSCGrayScale(A0) ; Blank the screen.
@EndBlank
Move.w dCtlRefNum(A1),D1 ; Get the drivers refNum.
@DevLoop Movea.l D0,A0 ; Get Handle to gDevice.
Movea.l (A0),A0 ; Make it a pointer.
Cmp.w gdRefNum(A0),D1 ; If this isnt our gDevice,
Bne.s @NextGD ; then just go on.
Btst #InBlanking,GFlags(A3) ; If weve blanked the screen, then
Bne.s @ClutIt ; temporarily act like weve got a CLUT.
Move.w #fixedType,gdType(A0) ; Otherwise, put things back.
Bra.s @Done ; Vamoose.
@ClutIt Move.w #clutType,gdType(A0) ; MacsBug is happier this way.
Bra.s @Done ; Vamoose.
@NextGD Move.l gdNextGD(A0),D0 ; If the next gDevices Handle isnt nil,
Bne.s @DevLoop ; then loop until done
@Done Movem.l (Sp)+,D0-D1/A0 ; Restore working registers.
Rts
;-----------------------------------------------------------------------------
; The Interrupt handler for Time Manager Task Built-In Video
;-----------------------------------------------------------------------------
;
; The new time manager sets A1 to point to the TTask block on entry
;
TimeManagerIH ; <H6> Thru next <H6>
MOVE.L A1,-(SP) ; save A1 (it's trashed by JVBLTask)
CLR.W D0 ; set slot zero in D0
MOVE.L JVBLTask,A0 ; call the VBL task manager
JSR (A0) ; with slot # in D0
MOVEA.L (SP)+,A1 ; restore A1 (ptr to TTask block) <3> djw
TST.W tmXQSize(A1) ; test the flag word to see if “interrupts” are on
; WARNING! - this field must be immediately after the TTask elem
BNE.S @Done ; if ≠ 0, then “interrupts” are disabled, so don't reprime
MOVEA.L A1,A0 ; get time task block addr in A0 <3> djw
MOVE.L #kDBLiteVBLTime,D0 ; delay for about 1/60th of a second
MOVE.L jPrimeTime,A1 ; point straight at the Time Manager dispatch vector
JSR (A1) ; start the delay going
@Done
RTS ; and return to caller <H6>
ENDWITH
END