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supermario/base/SuperMarioProj.1994-02-09/QuickDraw/DrawLine.a

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Bring in sources, and document
2019-06-29 15:17:50 +00:00
;
; File: DrawLine.a
;
; Copyright: © 1981-1990, 1992 by Apple Computer, Inc., all rights reserved.
;
; Change History (most recent first):
;
; <SM2> 6/11/92 stb <sm 6/9/92>stb Synched with QDciPatchROM.a; added comments to
; DrawLine, SkipSetup, FASTLINE, HTOGL, VLINE, FASTSLANT.
; <8> 12/13/90 SMC Refixed <7>. With KON.
; <7> 11/26/90 SMC Fixed call to StretchBits to use locmode with pattern bit
; forced. PnMode was being used. With BAL.
; <6> 10/31/90 SMC Fixed alpha channel bugs with BAL.
; <5> 9/17/90 BG Removed <3>. 040s are now behaving more reliably.
; <4> 7/20/90 gbm Change some identifiers to cease conflicting with interface
; files
; <3> 6/26/90 BG Added EclipseNOPs for flakey 040s.
; <2> 2/13/90 BAL Ensure that the initial bit offset is calculated in a long
; instead of a word so that lines drawn into really wide pixmaps
; don't freak out.
; <•1.6> 7/14/89 BAL For Aurora: Final CQD
; <1.5> 6/30/89 BAL Cleared runBuf(a6) before calling getSeek
; <•1.4> 5/29/89 BAL Blasting in 32-Bit QuickDraw version 1.0 Final
; <•1.3> 4/12/89 BAL Blasting in 32-Bit QuickDraw 1.0B1
; 1/22/89 BAL Made patVPos a long.
; 9/22/88 BAL Moved initialization of region state records into GetSeek.
; 9/19/88 BAL Altered to use common stack frame file 'Drawing Vars.a'
; 9/18/88 BAL Altered to get CRSRFLAG value from _BitsToPix; Removed
; references to PIXSRC;
; 11/8/87 BAL Fixed computation of bufSize for more accurate region clipping
; at at depths greater than 1. <C954>
; 11/7/87 BAL Fixed ChkPat to handle new patterns. <C945>
; 6/4/87 CRC preserve hilite mode across calls to colormap; set patmode in
; case user forgot
; 1/3/87 CRC pass color param to stretch
; 12/12/86 CRC Added support for arithmetic modes
; 10/9/86 EHB Added mask parameters to stretchbits calls
; 7/29/86 EHB Allocate EXPAT buffer on stack so long aligned
; 7/26/86 EHB Added support for expanded patterns
; 7/22/86 EHB Pass MODE to PatExpand
; 7/5/86 EHB Replaced SeekMask and GetXRtn with GetMask
; 6/20/86 EHB New params to COLORMAP; Added FCOLOR and BCOLOR to stack frame
; 6/18/86 EHB Call StretchBits instead of RgnBlt
; 6/15/86 EHB Make sure stack is longword aligned (for fast buffers); If one
; 1-bit region, play directly into RGNBUFFER Convert BitsToPix and
; use pixelSize
; 6/14/86 EHB Call GetXRtn to set expand routine for SeekMask; Added DSTPIX to
; stack frame
; 6/13/86 EHB Updated SeekMask to check rgn changed flag Moved SeekMask to
; another file; Rearranged stack frame with SeekMask stuff at top
; 6/10/86 EHB Modified to use 32-bit DrawSlab
; 6/5/86 EHB Clear flag bits from all references to rowBytes
BLANKS ON
STRING ASIS
MACHINE MC68020
;-----------------------------------------------------------------
;
; --> DRAWLINE.TEXT
;
;------------------------------------------------------------------
DrawLine PROC EXPORT
IMPORT SHFTTBL
Export steepBlitTab,shallowBlitTab,FastLine,FastSlant
;----------------------------------------------------------------
;
; PROCEDURE DRAWLINE(P1,P2: POINT);
;
; DRAWS A LINE CLIPPED TO CURRENT PORT'S CLIPRGN AND VISRGN
;
; P1 AND P2 ARE GIVEN IN LOCAL COORDINATES OF THEPORT.
;
;------------------------------------------------
;
; A6 OFFSETS OF PARAMETERS AFTER LINK:
;
PARAMSIZE EQU 8 ;SIZE OF PARAMETERS
P1 EQU PARAMSIZE+8-4 ;POINT
P2 EQU P1-4 ;POINT
;-------------------------------------------------
;
; A6 OFFSETS OF LOCAL VARIABLES AFTER LINK:
;
; STACK FRAME VARS USED BY SEEKMASK (CALLED BY STRETCHBITS, RGNBLT, DRAWARC, DRAWLINE)
;
&CurFile SETC 'DRAWLINE'
INCLUDE 'DrawingVars.a'
;-------------------------------------------------
; includes fixes as seen in QDciPatchROM.a <sm 6/9/92>stb
LINK A6,#VARSIZE ;ALLOCATE LOCAL VARS
MOVEM.L D0-D7/A1-A5,-(SP) ;SAVE REGS
MOVE.L SP,SAVESTK(A6) ;REMEMBER STACK FOR LATER
MOVE.L A5,SAVEA5(A6) ;REMEMBER GLOBAL PTR
CLR.L DSTMASKBUF(A6) ;ASSUME NO MASK
MOVE.L GRAFGLOBALS(A5),A0 ;POINT TO QUICKDRAW GLOBALS
MOVE.L WIDEOPEN(A0),BIGRGN(A6) ;STASH WIDEOPEN IN BIGRGN
MOVE.L THEPORT(A0),A3 ;POINT TO CURRENT GRAFPORT
TST PNVIS(A3) ;IS PNVIS NEGATIVE ?
BLT GOHOME ;YES, QUIT
MOVE.W PNMODE(A3),D1 ;get pen mode Start of <7>
_GetStreamMode ;strip off alpha bits
;this code moved up here from below at SET UP NEWPATTERN TO INDICATE OLD OR NEW STYLE PATTERN
BSET #3,D1 ;set the pattern bit in case the user forgot to
MOVEQ #$10,D0 ;1 past normal mode range
BTST #5,D1 ;arithmetic mode?
BEQ.S @noRith
CMP #$3A,D1 ;hilite?
BEQ.S @ok
MOVEQ #$30,D0 ;1 past arithmetic mode range
@noRith CMP D0,D1 ;greater than defined range?
BGT GOHOME
@ok MOVE D1,LOCMODE(A6) ;copy mode for colormap End of <7>
MOVE.L A3,PORT(A6) ;SAVE PORT FOR LATER
;----------------------------------------------------------------
;
; MAKE SURE THE STACK IS ON A LONGWORD BOUNDARY (FOR FAST BUFFERS)
;
MOVE.L SP,D1 ;GET THE STACK POINTER
AND.B #$FC,D1 ;FORCE LONG ALIGNMENT
MOVE.L D1,SP ;USE IT
;----------------------------------------------------
;
; CONVERT DSTBITS TO PIXMAP
; (A5 must contain global ptr)
;
LEA PORTBITS(A3),A1 ;GET POINTER TO DSTBITS
LEA DSTPIX(A6),A2 ;USE DSTPIX IN ITS PLACE
_BitsToPix ;CONVERT BITMAP
MOVE.L D1,REALBOUNDS(A6) ;SAVE REAL DST BOUNDS.TOPLEFT
MOVE.B D2,CRSRFLAG(A6) ;REMEMBER IF DST IS SCREEN <BAL 18Sep88>
;----------------------------------------------------
;
; CONVERT PIXEL DEPTH TO SHIFT AMOUNT TO AVOID MULTIPLIES
;
LEA SHFTTBL,A0 ;TO CONVERT DEPTH TO SHIFT
MOVE DSTPIX+PIXELSIZE(A6),D0 ;GET DST PIXEL SIZE
MOVEQ #0,D1 ;DEFAULT SHIFT = 0
MOVE.B 0(A0,D0),D1 ;GET SRC SHIFT
MOVE D1,DSTSHIFT(A6) ;AND SAVE DST SHIFT AMOUNT
;----------------------------------------------------------------
;
; SET UP NEWPATTERN TO INDICATE OLD OR NEW STYLE PATTERN
; ALSO SET UP LOCAL PATTERN POINTER, LOCPAT(A6)
;
LEA PNPAT(A3),A0 ;POINT TO THE PATTERN
MOVE.L A0,LOCPAT(A6) ;COPY PATTERN POINTER
TST PORTBITS+ROWBYTES(A3) ;IS THE DST OLD OR NEW?
;ciDrawLine from QDciPatchROM.a used to be right here
SMI NEWPATTERN(A6) ;FLAG = TRUE IF NEW PATTERN
;-------------------------------------------------------
;
; Check for color filtering. Alter mode and pattern accordingly.
;
MOVE.B HiliteMode,-(SP) ;preserve the hilite mode
CLR.B multiColor(A6) ;use fg/bg color
_COLORMAP ;CHECK AGAINST THECOLOR, THEFILTER
MOVE.B (SP)+,HiliteMode ;since stretch (and thus ColorMap) may be called later
;---------------------------------------------------------
;
; GET CLIPRGN AND VISRGN HANDLES AND DE-REFERENCE THEM
;
MOVE.L A3,A5 ;PUT GRAFPTR IN A5
MOVE.L CLIPRGN(A5),A2 ;GET CLIPRGN HANDLE
MOVE.L (A2),A2 ;GET CLIPRGN POINTER
MOVE.L VISRGN(A5),A3 ;GET VISRGN HANDLE
MOVE.L (A3),A3 ;GET VISRGN POINTER
;-------------------------------------------------------------
;
; SET UP LINERECT, THE RECTANGLE BOUNDING THE LINE AND PEN
;
MOVEM.W P2(A6),D1/D2/D3/D4 ;GET D1=V1, D2=H1, D3=V2, D4=H2
CMP D3,D1 ;IS V1 > V2 ?
BLE.S VOK2 ;NO, CONTINUE
EXG D1,D3 ;YES, SWAP VERT
VOK2 CMP D4,D2 ;IS H1 > H2 ?
BLE.S HOK2 ;NO, CONTINUE
EXG D2,D4 ;NO SWAP HORIZ
HOK2 ADD PNSIZE+H(A5),D4 ;ADD PEN WIDTH TO RIGHT
ADD PNSIZE+V(A5),D3 ;ADD PEN HEIGHT TO BOTTOM
MOVEM.W D1/D2/D3/D4,LINERECT(A6) ;STORE TOP, LEFT, BOTTOM, RIGHT
;-----------------------------------------------------------------------
;
; CALC MINRECT, THE INTERSECTION OF LINERECT, BITMAP BOUNDS,
; CLIPRGN BBOX, AND VISRGN BBOX. QUIT IF NO INTERSECTION.
;
PEA LINERECT(A6) ;PUSH LINE RECT
PEA DSTPIX+BOUNDS(A6) ;PUSH PIXMAP BOUNDS
PEA RGNBBOX(A2) ;PUSH CLIPRGN BBOX
PEA RGNBBOX(A3) ;PUSH VISRGN BBOX
MOVE #4,-(SP) ;PUSH NRECTS=4
PEA MINRECT(A6) ;PUSH DST ADDR
_RSECT ;CALC INTERSECTION
BEQ GOHOME ;QUIT IF NO INTERSECT
;-----------------------------------------------------------
;
; HIDE CURSOR IF CURSOR INTERSECTS MINRECT AND DST IS SCREEN.
; (A5 must contain global ptr)
;
MOVE.L SAVEA5(A6),A5 ;GET GLOBAL PTR
TST.B CRSRFLAG(A6) ;IS DST TO A SCREEN? <BAL 19Sep88>
BEQ.S NOTSCRN ;=>NO
PEA MINRECT(A6) ;PUSH SHIELDRECT PARAMETER
MOVE.L REALBOUNDS(A6),-(SP) ;PUSH DELTA FOR GLOBAL
_SHIELDCURSOR ;HIDE CURSOR IF IT INTERSECTS
NOTSCRN MOVE.L PORT(A6),A5 ;GET BACK THEPORT
;-----------------------------------------------------------
;
; CHECK FOR BOTH VISRGN AND CLIPRGN RECTANGULAR
;
CLR.B FASTFLAG(A6) ;FASTFLAG := FALSE
CMP #10,RGNSIZE(A2) ;IS CLIPRGN RECTANGULAR ?
BNE.S FLAGOK ;NO, CONTINUE
CMP #10,RGNSIZE(A3) ;IS VISRGN RECTANGULAR ?
BEQ.S CKPAT ;YES, CONTINUE
;-----------------------------------------------------------
;
; If only visRgn is non-rectangular, then check if
; its intersection with minrect would be rectangular.
; IF TrimRect(visRgn,minRect) then treat as rectangular.
;
MOVE.L visRgn(A5),-(SP) ;push rgnHandle
PEA minRect(A6) ;push addr of minRect
MOVE.W #-1,-(SP) ;pass Trim = True
_TrimRect ;call trimRect
BLT show ;quit if intersection empty
BGT.S FLAGOK ;continue if non-rectangular
;-----------------------------------------------------------
;
; CHECK FOR BLACK OR WHITE PATTERN
;
CKPAT BTST #5,LocMode+1(A6) ;an arithmetic mode?
BNE.S FlagOK ;skip fast case if so
MOVE.L LOCPAT(A6),A0 ;POINT TO PATTERN
TST.B NEWPATTERN(A6) ;is it a new pattern? <C945 07Nov87 BAL>
BEQ.S @oldPat ;=>no, skip pixpat fields <C945 07Nov87 BAL>
MOVE.L (a0),a0 ;get the pixpat handle <C945 07Nov87 BAL>
MOVE.L (a0),a0 ;get the pixpat pointer <C945 07Nov87 BAL>
TST PATTYPE(A0) ;is it an old-style pattern? <C945 07Nov87 BAL>
BNE.S FLAGOK ;=>no, skip fast case <C945 07Nov87 BAL>
MOVE.L patData(a0),a0 ;get handle to pattern data <C945 07Nov87 BAL>
MOVE.L (a0),a0 ;get pattern ptr <C945 07Nov87 BAL>
@oldPat MOVE.L (A0)+,D0 ;GET 1ST HALF OF PATTERN
CMP.L (A0)+,D0 ;IS IT SAME AS 2ND HALF ?
BNE.S FLAGOK ;NO, CONTINUE
NOT.L D0 ;IS PATTERN BLACK ?
BEQ.S YESFLAG ;YES, WE MADE IT
NOT.L D0 ;IS PATTERN WHITE ?
BNE.S FLAGOK ;NO, CONTINUE
EOR #4,LOCMODE(A6) ;YES, ALTER MODE AS IF BLACK
YESFLAG ST FASTFLAG(A6) ;RECT CLIPPED AND BLACK
;-----------------------------------------------------------
;
; fast case: map mode into black,xor,white, or do-nothing
;
MOVEQ #7,D0 ;GET 3 BIT MASK
AND LOCMODE(A6),D0 ;GET 3 BITS OF MODE
MOVE.B MODEMAP(D0),D0 ;MAP TO BLACK,XOR,WHITE,NOP
BMI show ;QUIT IF DO-NOTHING MODE
MOVE D0,LOCMODE(A6) ;UPDATE MODE
BRA.S FLAGOK ;AND CONTINUE
MODEMAP DC.B 0,0,1,2,2,255,255,255
FLAGOK
;-----------------------------------------------------------
;
; GET THE TWO LINE ENDPOINTS INTO REGISTERS
; AND CHECK FOR HORIZONTAL OR VERTICAL LINE
;
MOVEM.W P2(A6),D1/D2/D3/D4 ;GET D1=V2, D2=H2, D3=V1, D4=H1
CMP D2,D4 ;H1=H2 ?
BEQ.S HVLINE ;YES, DO VERTICAL LINE
CMP D1,D3 ;NO, IS V2 > V1 ?
BGT.S SLANTED ;YES, DRAW SLANTED LINE
BLT.S VSWAP ;SWAP POINTS AND DRAW SLANTED
;ELSE V1=V2, DO HORIZONTAL
;-----------------------------------------------------------
;
; LINE IS EITHER HORIZONTAL OR VERTICAL.
; CHECK FOR ONE DOT LINE, BLACK OR WHITE PATTERN, AND
; CLIPRGN AND VISRGN BOTH RECTANGULAR. IF SO, OPTIMIZE FAST LINES.
;
HVLINE TST.B FASTFLAG(A6) ;RECT CLIPPED AND BLACK ?
BEQ.S NOTFAST ;NO, CONTINUE
CMP.L #$00010001,PNSIZE(A5) ;IS PEN 1 BY 1 ?
bne.s NotFast ;NO, CONTINUE
_FastLineJmp ;YES, DO IT FAST !
;--------------------------------------------------------------------
;
; NOT FASTLINE. PUSH PARAMS AND CALL STRETCHBITS FOR HORIZ OR VERT LINE.
;
NOTFAST PEA PORTBITS(A5) ;PUSH SRCBITS = PORTBITS
CLR.L -(SP) ;NO MASKBITS
PEA PORTBITS(A5) ;PUSH DSTPIX
PEA MINRECT(A6) ;PUSH SRCRECT = DSTRECT
CLR.L -(SP) ;NO MASKRECT
PEA MINRECT(A6) ;PUSH DSTRECT
MOVE PNMODE(A5),D0 ;GET MODE <8>
AND #$FCFF,D0 ;STRIP SOME BITS <8>
BSET #3,D0 ;set the pattern bit in case the user forgot to <8>
MOVE D0,-(SP) ;PUSH CLEANED MODE <8>
PEA PNPAT(A5) ;PUSH PATTERN
MOVE.L CLIPRGN(A5),-(SP) ;PUSH CLIPRGN HANDLE
MOVE.L VISRGN(A5),-(SP) ;PUSH VISRGN HANDLE
MOVE.L BIGRGN(A6),-(SP) ;PUSH SAVED WIDEOPEN
MOVE.L SAVEA5(A6),A5 ;GET GLOBAL PTR
CLR -(SP) ;pass multicolor flag false
_STRETCHBITS ;DRAW THE HORIZ OR VERT LINE
BRA show ;RESTORE CURSOR AND QUIT
;-------------------------------------------------------------
;
; THE LINE IS SLANTED. SORT VERTICALLY
; AND DRAW TOP TO BOTTOM AS HORIZONTAL SLABS.
;
VSWAP EXG D1,D3 ;SORT POINTS BY VERTICAL
EXG D2,D4 ;SWAP HORIZ TO MATCH
SLANTED MOVE D3,D0 ;COPY LINE BOTTOM
ADD PNSIZE+V(A5),D0 ;ADD PEN HEIGHT
CMP minRect+TOP(A6),D0 ;IS RESULT <= minRect TOP ? <07Jul89>
BLE show ;YES, RESTORE CURSOR AND QUIT
CMP minRect+BOTTOM(A6),D1 ;IS TOP >= minRect BOTTOM ? <07Jul89>
BGE show ;YES, RESTORE CURSOR AND QUIT
;-------------------------------------------------------------
;
; SET UP INITIAL FIXED POINT LEFTEDGE AND RIGHTEDGE
; AND CHECK FOR ZERO PENSIZE.
;
MOVE.W D2,LEFTEDGE(A6) ;LEFTEDGE.INT := TOP HORIZ
MOVE.W #$8000,LEFTEDGE+2(A6) ;LEFTEDGE.FRACT := 1/2
MOVE.L LEFTEDGE(A6),RIGHTEDGE(A6) ;RIGHTEDGE:=LEFTEDGE
MOVE PNSIZE+H(A5),D0 ;GET PEN WIDTH
BLE show ;QUIT IF PENWIDTH <= 0
ADD.W D0,RIGHTEDGE(A6) ;ADD TO RIGHTEDGE.INT
MOVE PNSIZE+V(A5),D6 ;GET PEN HEIGHT
BLE show ;QUIT IF PEN HEIGHT <= 0
;----------------------------------------------------
;
; CALC FIXED POINT SLOPE = FixRatio(dh,dv);
;
SUB D2,D4 ;CALC DH
SUB D1,D3 ;CALC DV
ext.l D3
moveq #0,d7 ;clear out high word
move.w d4,d7 ;copy DH to d7
swap D7
DIVS.l D3,D7 ;CALC FIXED POINT SLOPE DH/DV
MOVE.L D7,SLOPE(A6) ;SAVE FOR LATER
;
; CALC adjust := pen height * slope
;
move.l d7,d5 ;assume height is 1
cmp.w #1,d6 ;is pen height 1
beq.s @gotAdjust
ext.l d6
MULS.L d6,d5 ;CALC FixMul(pnSize.v,slope)
@gotAdjust
;
; ADJUST LEFTEDGE AND RIGHTEDGE DEPENDING ON SIGN AND MAGNITUDE OF SLOPE
; Set steepFlag in A2: 0->shallow; 1->down&right; -1->down&left
sub.l a2,a2 ;assume shallow
MOVE.L D7,D0 ;COPY SLOPE
ASR.L #1,D0 ;CALC SLOPE/2
ADD.L D0,LEFTEDGE(A6) ;ADD SLOPE/2 TO LEFT EDGE
ADD.L D0,RIGHTEDGE(A6) ;ADD SLOPE/2 TO RIGHT EDGE
TST.L D7 ;IS SLOPE NEGATIVE ?
BMI.S NEGSLOPE ;YES, CONTINUE
SUB.L D5,LEFTEDGE(A6) ;SUBTRACT ADJUST FROM LEFTEDGE
CMP.L #$00010000,D7 ;IS SLOPE < ONE ?
BGT.S LESSV1 ;NO, BRANCH
BEQ.S Pos45 ;NO, BRANCH
MOREV1 ADD.L D7,LEFTEDGE(A6) ;ADD SLOPE TO LEFTEDGE
addq #1,a2 ;remember steep and to right
BRA.S SLOPEOK ;CONTINUE
Pos45 addq #1,a2 ;remember 45°
LESSV1 SUB.W #1,RIGHTEDGE(A6) ;RIGHTEDGE := RIGHTEDGE - 1
BRA.S SLOPEOK ;CONTINUE
;----------------------------------------------------
;
; SLOPE IS NEGATIVE
;
NEGSLOPE SUB.L D5,RIGHTEDGE(A6) ;SUBTRACT ADJUST FROM RIGHTEDGE
CMP.L #$FFFF0000,D7 ;IS SLOPE > -ONE ?
BLT.S LESSV2 ;NO, CONTINUE
MOREV2 ADD.L D7,RIGHTEDGE(A6) ;ADD SLOPE TO RIGHTEDGE
subq #1,a2 ;remember steep and to left
BRA.S SLOPEOK
LESSV2 ADD.W #1,LEFTEDGE(A6) ;LEFTEDGE := LEFTEDGE + 1
SLOPEOK MOVEM.W MINRECT(A6),D1/D2/D3/D4 ;GET MINRECT TOP,LEFT,BOTTOM,RIGHT
;
; ADJUST LEFTEDGE AND RIGHTEDGE IF LINE WAS CLIPPED VERTICALLY
;
CMP LINERECT+TOP(A6),D1 ;DID TOP GET CLIPPED ?
BEQ.S TOPOK ;NO, CONTINUE
MOVE D1,D0
SUB LINERECT+TOP(A6),D0 ;CALC DISCARD AMOUNT
EXT.L D0 ;MAKE IT LONG
MOVE.L D7,D5 ;GET 32 BIT SLOPE
MULS.L D0,D5 ;SLOPE * SCANS CLIPPED
ADD.L D5,LEFTEDGE(A6) ;BUMP LEFTEDGE TO NEW TOP
ADD.L D5,RIGHTEDGE(A6) ;BUMP RIGHTEDGE TO NEW TOP
;-----------------------------------------------------------
;
; LINE IS SLANTED. IF |SLOPE| <= 1 THEN
; CHECK FOR ONE DOT LINE, BLACK OR WHITE PATTERN, AND CLIPRGN
; AND VISRGN BOTH RECTANGULAR. IF SO THEN OPTIMIZE.
;
TOPOK
; bchg #0,0 ;debugging code
; beq.s CalcBufLeft
TST.B FASTFLAG(A6) ;RECT CLIPPED AND BLACK ?
BEQ.S CalcBufLeft ;NO, CONTINUE
cmp.w LINERECT+left(a6),D2 ;is MinRect.Left>Line's left edge?
bgt.s CalcBufLeft ;horizontally clipped!
cmp.w LINERECT+right(a6),D4 ;is MinRect.Right<Line's right edge?
blt.s CalcBufLeft ;horizontally clipped!
CMP.L #$00010001,PNSIZE(A5) ;IS PEN 1 BY 1 ?
bne.s CalcBufLeft ;no, continue
_FastSlantJmp ;YES, DO IT FAST !
;Assumes: D1,D2,D3,D4 = MinRect T,L,B,R
; D7 = slope (16.16)
CalcBufLeft
;-----------------------------------------------------------
;
; CALC BUFLEFT
;
;D2 = MINRECT LEFT
MOVE DSTSHIFT(A6),D5 ;GET SHIFT FOR PIXEL DEPTH
SUB DSTPIX+BOUNDS+LEFT(A6),D2 ;CONVERT TO GLOBAL COORDS
ext.l d2 ;make it a long <BAL 17Jan89>
LSL.l D5,D2 ;CONVERT PIXELS TO BITS
AND.l #~$1f,D2 ;TRUNC TO MULT OF 32 BITS
MOVE.l D2,D1 ;GET BUFLEFT IN BITS
LSR.l #3,D1 ;CONVERT BITS TO BYTES
MOVE D1,PATHPOS(A6) ;AND SAVE AS HORIZONTAL PATTERN BASE
LSR.l D5,D2 ;CONVERT BITS TO PIXELS
ADD DSTPIX+BOUNDS+LEFT(A6),D2 ;CONVERT BACK TO GLOBAL
MOVE D2,BUFLEFT(A6) ;SAVE AS BUFLEFT
;
; IF FASTFLAG, THEN SKIP REGION SETUP
;
TST.B FASTFLAG(A6) ;RECT CLIPPED AND BLACK ?
BNE SKIPSETUP ;YES, DON'T WASTE TIME WITH SETUP
;_________________________________________________________________________________________
;
; CALC expansion buffer = [ (minRect.right-minRect.left) div 32 + 1 ] * pixelsize - 1
; CALC bufSize = [ (minRect.right-minRect.left) * pixelsize - 1 ] div 32 <C954> 08Nov87 BAL
;
;D4 = MINRECT RIGHT
SUB D2,D4 ;CALC MAXH-BUFLEFT
move d4,d0 ;save for expansion scanline buffer <C954>
ext.l d4 ;clear out high word <C954>
lsl.l d5,d4 ;convert to bits <C954>
subq.l #1,d4 ;force downward round <C954>
LSR.l #5,D4 ;GET NUMBER OF LONGS IN SCANBUF - 1 <C954>
MOVE D4,BUFSIZE(A6) ;BUFSIZE = # LONGS -1 <C954>
LSR #5,D0 ;get (pixels in scanbuf)/32 <C954>
ADDQ #1,D0 ;MAKE IT ONE BASED
LSL D5,D0 ;CONVERT PIXELS TO BITS
SUBQ #1,D0 ;MAKE 0 BASED AGAIN
;
; ALLOCATE AND CLEAR A SCANLINE BUFFER FOR THE COMPOSITE MASK
;
CLRMASK CLR.L -(SP) ;ALLOCATE AND CLEAR ONE LONG
DBRA D0,CLRMASK ;LOOP TILL DONE
MOVE.L SP,RGNBUFFER(A6) ;REMEMBER WHERE RGNBUFFER IS
;--------------------------------------------------------------------
;
; ALLOCATE BUFFERS AND INIT STATE RECORDS FOR EACH NON-RECT REGION
; GET SEEK ROUTINE INTO SEEKMASK(A6)
; GET EXPAND ROUTINE INTO EXRTN(A6) FOR SEEK ROUTINE
; Clobbers: A0-A3, D0-D4
;
lea Show,a0 ;get go home routine
move.l a0,goShow(a6) ;pass to getSeek <BAL 21Mar89>
move.l maskbc,StackFree(a6) ;pretend lots of stack <BAL 21Mar89>
clr.l DstRow(a6) ;flag as seeking down
clr.l runBuf(a6) ;don't use run clipping <1.5> BAL
MOVE.L VISRGN(A5),-(SP) ;PUSH VIS RGNHANDLE
MOVE.L CLIPRGN(A5),-(SP) ;PUSH CLIP RGNHANDLE
MOVE.L #1,-(SP) ;PUSH HANDLE COUNT - 1
_GETSEEK ;GET EXPAND ROUTINE INTO EXRTN(A6)
;AND SEEK ROUTINE INTO SEEKMASK(A6)
SKIPSETUP
;------------------------------------
;
; CALC STARTING DSTLEFT
;
; as seen in QDciPatchROM.a at TryLine, fixes both patches on _FastSlabMode and _GetSeek <sm 6/9/92>stb
MOVE MINRECT+TOP(A6),D1
SUB DSTPIX+BOUNDS+TOP(A6),D1 ;CONVERT MINV TO GLOBAL COORDS
MOVE DSTPIX+ROWBYTES(A6),D0 ;get dst rowbytes
AND #nuRBMask,D0 ;clear off flag bits
MOVE D0,DSTROW(A6) ;SAVE FOR LATER
MULS D0,D1 ;MULT BY DST ROWBYTES; BAL 02Dec88
ADD.L DSTPIX+BASEADDR(A6),D1 ;ADD START OF BITMAP
MOVE BUFLEFT(A6),D2 ;GET BUFLEFT
SUB DSTPIX+BOUNDS+LEFT(A6),D2 ;CONVERT BUFLEFT TO GLOBAL
ext.l d2 ;clear out high end <BAL 13Feb90>
MOVE DSTSHIFT(A6),D7 ;GET PIXEL TO BIT SHIFT AMOUNT
LSL.L D7,D2 ;CONVERT PIXELS TO BITS <BAL 13Feb90>
LSR.L #3,D2 ;CONVERT BITS TO BYTES <BAL 13Feb90>
; EXT.L D2 ;CLR HI WORD <BAL 13Feb90>
ADD.L D2,D1 ;ADD HORIZ BYTE OFFSET
MOVE.L D1,DSTLEFT(A6) ;SAVE AS DSTLEFT
;----------------------------------------------------
;
; MAKE LEFTEDGE,RIGHTEDGE,MINRECT RELATIVE TO BUFFER LEFT
;
MOVE BUFLEFT(A6),D1
SUB.W D1,LEFTEDGE(A6) ;ADJUST LEFTEDGE.INT
SUB.W D1,RIGHTEDGE(A6) ;ADJUST RIGHTEDGE.INT
SUB D1,MINRECT+LEFT(A6)
SUB D1,MINRECT+RIGHT(A6)
;------------------------------------------------------------
;
; TAKE FAST OR SLOW OUTER CONTROL LOOP FOR SLANTED LINES:
;
TST.B fastFlag(A6) ;ARE WE RECT CLIPPED BLACK ?
BEQ.S GOSLOW ;NO, CONTINUE
MOVE LOCMODE(A6),D2 ;GET (ALTERED) PEN MODE
_FastSlabMode ;Get fast case jump in A4
LEA MINRECT(A6),A3 ;POINT TO MINRECT
MOVE.L SLOPE(A6),D7 ;GET FIXED POINT SLOPE
MOVE.L DSTLEFT(A6),A5 ;GET DSTLEFT
MOVE.L FCOLOR(A6),D4 ;PASS FCOLOR
MOVE.L BCOLOR(A6),D5 ;AND BACKCOLOR
MOVE MINRECT+BOTTOM(A6),D6 ;GET MINRECT BOTTOM
SUB MINRECT+TOP(A6),D6 ;CALC HEIGHT
SUB #1,D6 ;MINUS 1 FOR DBRA COUNT
;-----------------------------------------------------------
;
; Switch to 32 bit addressing mode
;
moveq #true32b,d0 ;switch to 32 bit addressing
_rSwapMMUMode ;get previous mode in d0.b (can trash a0/a1/a2, d0/d1/d2)
move.b d0,MMUsave(a6) ;save previous state for later
NXTFAST MOVE.W LEFTEDGE(A6),D1 ;GET LEFTEDGE.INT
MOVE.W RIGHTEDGE(A6),D2 ;GET RIGHTEDGE.INT
MOVE.L A5,A1 ;INIT DSTPTR TO LEFT
MOVE.W DSTSHIFT(A6),D0 ;GET PIXEL TO BIT SHIFT AMOUNT
_DrawSlab ;DRAW ONE SLAB IN PENMODE
ADD DSTROW(A6),A5 ;BUMP DST TO NEXT ROW
ADD.L D7,LEFTEDGE(A6) ;ADD SLOPE TO LEFT EDGE
ADD.L D7,RIGHTEDGE(A6) ;ADD SLOPE TO RIGHT EDGE
DBRA D6,NXTFAST ;LOOP FOR ALL SCANLINES
BRA DONE ;AND QUIT
GOSLOW
;------------------------------------------------------------------
;
; SET INVERSE FLAG AND CALL PATEXPAND TO EXPAND PATTERN
;
CLR.L D7 ;SAY NOT INVERTED
MOVE LOCMODE(A6),D2 ;GET (ALTERED) PEN MODE
BTST #5,D2 ;a new arithmetic mode?
BNE.S NOTINV ;if so, no invert bit to test
BCLR #2,D2 ;TEST AND CLR INVERT BIT
BEQ.S NOTINV ;SKIP IF NOT INVERTED
NOT.L D7 ;INVERTED; D7 GETS ALL 1'S
NOTINV MOVE.L SAVEA5(A6),A5 ;GET GLOBAL PTR
_PATEXPAND ;EXPAND 8 BYTES TO 16 LONGS
;SETUP PATROW,PATHMASK,PATVMASK
MOVE PATROW(A6),D1 ;GET THE PATTERN ROWBYTES
BNE.S DONEW ;=>NON-ZERO, IT'S A NEW PATTERN
MOVEQ #$F,D6 ;ELSE 16 ROWS OF PATTERN
MOVEQ #$4,D1 ;GET PATTERN ROWBYTES INTO D1
MOVE D1,PATROW(A6) ;AND SET PATTERN ROWBYTES
MOVE #$3,PATHMASK(A6) ;HORIZONTAL MASK FOR PATTERN
MOVE #$3F,PATVMASK(A6) ;VERTICAL MASK FOR PATTERN
BRA.S DOOLD ;=>GO GET STARTING OFFSET INTO PATTERN
; NEW PATTERN. SET STARTING VERT POSITION.
DONEW MOVEQ #0,D6 ;CLEAR HIGH WORD
MOVE PATVMASK(A6),D6 ;GET VERTICAL MASK
ADDQ #1,D6 ;CONVERT TO COUNT
DIVU PATROW(A6),D6 ;DIVIDE BY ROWSIZE
SUBQ #1,D6 ;GET ROWS OF PATTERN
DOOLD AND MINRECT+TOP(A6),D6 ;GET TOP VERT LOCAL COORD
MULU D1,D6 ;CALC OFFSET INTO PATTERN
MOVE.l D6,PATVPOS(A6) ;SAVE AS PATVPOS <BAL 22Jan89>
; GET SLOW SLABMODE IN A4 (RELIES ON PATROW, SET UP BY PATEXPAND)
MOVE LOCMODE(A6),D2 ;GET (ALTERED) PEN MODE
_SlabMode ;GET DrawSlab CASE JUMP IN A4
;-----------------------------------------------------------
;
; Switch to 32 bit addressing mode
;
moveq #true32b,d0 ;switch to 32 bit addressing
_rSwapMMUMode ;get previous mode in d0.b (can trash a0/a1/a2, d0/d1/d2)
move.b d0,MMUsave(a6) ;save previous state for later
; FOR EACH SLAB, MAKE MASK BUFFER CURRENT AND DRAW SLAB
MOVE MINRECT+TOP(A6),VERT(A6) ;INIT CURRENT VERT:=MINV
MOVE.L DSTLEFT(A6),A5 ;GET DSTLEFT
MOVE.L FCOLOR(A6),D4 ;PASS FCOLOR
MOVE.L BCOLOR(A6),D5 ;AND BACKCOLOR
MOVE.L SLOPE(A6),D7 ;GET FIXED POINT SLOPE
NXTMASK JSR ([SEEKMASK,A6]) ;MAKE MASK BUFFER CURRENT
LEA MINRECT(A6),A3 ;POINT TO MINRECT
LEA ([EXPAT,A6],D6.l),A0 ;GET pointer to THIS ROW'S PATTERN
MOVE.L (A0),D6 ;set up the pattern
MOVE.W LEFTEDGE(A6),D1 ;GET LEFTEDGE.INT
MOVE.W RIGHTEDGE(A6),D2 ;GET RIGHTEDGE.INT
MOVE.L A5,A1 ;INIT DSTPTR TO LEFT
MOVE.L RGNBUFFER(A6),A2 ;INIT MASKPTR TO LEFT
MOVE.W DSTSHIFT(A6),D0 ;GET SHIFT FOR PIXEL DEPTH
_DrawSlab ;DRAW ONE SLAB IN PENMODE
MOVE.l PATVPOS(A6),D6 ;GET PATVPOS <BAL 22Jan89>
ADD PATROW(A6),D6 ;BUMP TO NEXT SCAN
AND PATVMASK(A6),D6 ;WRAP AT END OF PATTERN
MOVE.l D6,PATVPOS(A6) ;SAVE PATVPOS FOR DRAWSLAB <BAL 22Jan89>
ADD DSTROW(A6),A5 ;BUMP DST TO NEXT ROW
ADD.L D7,LEFTEDGE(A6) ;ADD SLOPE TO LEFT EDGE
ADD.L D7,RIGHTEDGE(A6) ;ADD SLOPE TO RIGHT EDGE
ADD #1,VERT(A6) ;BUMP CURRENT VERT FOR SEEKMASK
MOVE VERT(A6),D0 ;GET CURRENT VERT
CMP MINRECT+BOTTOM(A6),D0 ;AT BOTTOM YET ?
BLT NXTMASK ;NO, LOOP ALL SCAN LINES
DONE move.b MMUsave(a6),d0 ;get previous MMU state in d0
_rSwapMMUMode ;get previous mode in d0.b (can trash a0/a1/a2, d0/d1/d2)
SHOW MOVE.L SAVEA5(A6),A5 ;GET GLOBAL PTR
TST.B CRSRFLAG(A6) ;DRAWING TO SCREEN?
BEQ.S GOHOME ;=>NO, JUST RETURN
_SHOWCURSOR ;RESTORE CURSOR
GOHOME BSET #hiliteBit,HiliteMode ;reset hilite override, in case colormap was skipped
MOVE.L SAVESTK(A6),SP ;STRIP BUFFER
MOVEM.L (SP)+,D0-D7/A1-A5 ;RESTORE REGISTERS
UNLINK PARAMSIZE,'DRAWLINE'
ALIGN Alignment
;-------------------------------------------------------
;
; SET UP AND DRAW A FAST HORIZONTAL OR VERTICAL LINE.
;
; as seen in QDciPatchROM.a <sm 6/9/92>stb
FASTLINE
;-----------------------------------------------------------
;
; Switch to 32 bit addressing mode
;
moveq #true32b,d0 ;switch to 32 bit addressing
move.w d1,-(sp) ;save a register
_rSwapMMUMode ;get previous mode in d0.b (can trash a0/a1/a2, d0/d1/d2)
move.w (sp)+,d1 ;restore d1
move.b d0,MMUsave(a6) ;save previous state for later
MOVE.L alphaMask(A6),D4 ;get alpha mask <6>
CMP D1,D3 ;IS LINE HORIZONTAL ?
BNE VLINE ;NO, MUST BE VERTICAL
BSR HVSETUP ;GET DSTPTR,ROWBYTES,HGLOBAL
MOVEQ #-1,D6 ;GET ONES IN D6
LSR.L D0,D6 ;CONVERT TO LEFTMASK
MOVE MINRECT+RIGHT(A6),D2 ;GET MINRECT RIGHT
SUB DSTPIX+BOUNDS+LEFT(A6),D2 ;CONVERT TO GLOBAL
EXT.L D2 ;MAKE IT LONG
LSL.L D3,D2 ;CONVERT PIXELS TO BITS
MOVEQ #$1F,D0 ;NEED RIGHT MOD 32
AND.L D2,D0 ;MAKE A COPY OF RIGHT
MOVEQ #-1,D3 ;GET ONES IN D3
LSR.L D0,D3 ;SHIFT IN 0'S FOR LEFTMASK
NOT.L D3 ;CONVERT TO RIGHTMASK
AND.L D4,D6 ;clip left mask with alpha mask <6>
AND.L D4,D3 ;clip right mask with alpha mask <6>
LSR.L #5,D2 ;CONVERT BITS TO LONGS
CMP #1,LOCMODE(A6) ;WHICH MODIFIED MODE ?
BLT.S HSET ;BR IF FOREGROUND
BEQ.S HTOGL ;BR IF XOR
;ELSE BACKGROUND
;------------------------------------------------------
;
; DRAW A HORIZONTAL LINE IN THE BACKGROUND COLOR (NORMALLY WHITE)
;
MOVE.L BCOLOR(A6),D5 ;GET THE COLOR
BRA.S HDRAW
;--------------------------------------------
;
; DRAW A HORIZONTAL LINE IN THE FOREGROUND COLOR (NORMALLY BLACK)
;
HSET MOVE.L FCOLOR(A6),D5 ;GET THE FOREGROUND COLOR
HDRAW SUB D1,D2 ;CALC LONG COUNT
BEQ.S ALLONE ;BR IF ALL IN ONE LONG
MOVE.L D5,D1 ;COPY COLOR
AND.L D6,D1 ;MASK COLOR FOR LEFT EDGE
NOT.L D6 ;GET NOT LEFTMASK
AND.L (A4),D6 ;PUNCH HOLE IN DEST
OR.L D1,D6 ;COMBINE SRC AND DST
MOVE.L D6,(A4)+ ;AND DROP COLOR IN
SUB #1,D2 ;DEC LONG COUNT
BEQ.S DOEND ;BR IF NO UNMASKED LONG
NOT.L D4 ;reverse alpha mask <6>
BEQ.S DOONE ;use normal loops if all ones <6>
;
; <6> Draw horizontal line using alpha mask
;
ALPHALINE
MOVE.L (A4),D0 ;get long of dst
EOR.L D5,D0 ;apply color
AND.L D4,D0 ;mask with alpha mask
EOR.L D5,D0 ;reapply color
MOVE.L D0,(A4)+ ;put result to dst
DBRA D2,ALPHALINE ;do another long
BRA.S DOEND ;all done
DOTWO MOVE.L D5,(A4)+ ;FILL A LONG WITH COLOR
DOONE MOVE.L D5,(A4)+ ;FILL ANOTHER LONG
SUB #2,D2 ;ANY UNMASKED LONGS LEFT ?
DOMORE BGT DOTWO ;YES, AT LEAST TWO LONGS
BEQ DOONE ;YES, FINISH UP LAST LONG
DOEND AND.L D3,D5 ;MASK SOURCE FOR RIGHT EDGE
NOT.L D3 ;GET NOTMASK
AND.L (A4),D3 ;PUNCH HOLE IN DST DATA
OR.L D5,D3 ;COMBINE SRC AND DST
MOVE.L D3,(A4) ;AND DROP COLOR IN
BRA.S DONE ;RESTORE CURSOR AND QUIT
ALIGN Alignment
ALLONE AND.L D3,D6 ;COMBINE LEFT AND RIGHT MASKS
AND.L D6,D5 ;GET MASKED COLOR
NOT.L D6 ;GET NOTMASK
AND.L (A4),D6 ;PUNCH OUT DESTINATION
OR.L D5,D6 ;COMBINE SRC AND DST
MOVE.L D6,(A4) ;DRAW LINE
BRA.S DONE ;RESTORE CURSOR AND QUIT
ALIGN Alignment
; as seen in QDciPatchROM.a <sm 6/9/92>stb
;--------------------------------------------------
;
; DRAW AN XOR HORIZONTAL LINE
;
HTOGL SUB D1,D2 ;CALC LONGCOUNT
BEQ.S ONETOGL ;BR IF ALL IN ONE LONG
EOR.L D6,(A4)+ ;DO LEFT LONG WITH MASK
SUB #1,D2 ;DEC LONG COUNT
BEQ.S ENDTOGL ;BR IF NO UNMASKED LONGS
BRA.S TOGLONE ;SEE IF ANY LONGS LEFT TO DO
TOGLTWO EOR.L D4,(A4)+ ;INVERT A LONG <6>
TOGLONE EOR.L D4,(A4)+ ;INVERT ANOTHER LONG <6>
SUB #2,D2 ;ANY UNMASKED LONGS LEFT ?
TOGLMORE BGT TOGLTWO ;YES, AT LEAST TWO LONGS
BEQ TOGLONE ;YES, FINISH UP LAST LONG
ENDTOGL EOR.L D3,(A4) ;DRAW LINE
BRA.S DONE ;RESTORE CURSOR AND QUIT
ONETOGL AND.L D3,D6 ;COMBINE LEFT AND RIGHT MASK
EOR.L D6,(A4) ;DRAW LINE
BRA.S DONE ;RESTORE CURSOR AND QUIT
ALIGN Alignment
; as seen in QDciPatchROM.a <sm 6/9/92>stb
;-------------------------------------------------------
;
; DRAW A ONE PIXEL WIDE VERTICAL LINE.
;
VLINE BSR.S HVSETUP ;GET DSTPTR,ROWBYTES,HGLOBAL
MOVEQ #-1,D2 ;GET ONES IN D2
LSR.L D0,D2 ;CONVERT TO LEFTMASK (LEFT MOD 32 IN D0)
MOVE.L D2,D0 ;GET LEFTMASK
MOVE DSTPIX+PIXELSIZE(A6),D1 ;GET PIXEL SIZE
LSR.L D1,D0 ;SHIFT BY PIXEL SIZE FOR RIGHT EDGE
NOT.L D0 ;MAKE IT A RIGHTMASK
AND.L D0,D2 ;AND RIGHTMASK INTO LEFTMASK
AND.L D4,D2 ;MASK WITH ALPHA MASK <6>
MOVE MINRECT+BOTTOM(A6),D1 ;GET BOTTOM
SUB MINRECT+TOP(A6),D1 ;CALC HEIGHT
SUB #1,D1 ;INIT HEIGHT COUNT
CMP #1,LOCMODE(A6) ;WHICH MODIFIED MODE ?
BLT.S VSET ;BR IF FOREGROUND
BEQ.S VTOGL ;BR IF XOR
VCLR MOVE.L BCOLOR(A6),D5 ;GET BACKGROUND COLOR
BRA.S VDRAW ;=>AND DO LINE
VSET MOVE.L FCOLOR(A6),D5 ;GET FOREGROUND COLOR
VDRAW BEQ.S VAND ;COLOR IS ALL 0's SO JUST AND
MOVE.L D5,D0 ;COPY COLOR
NOT.L D0 ;WAS IT ALL 1's?
BEQ.S VOR ;YES, JUST NEED TO OR
AND.L D2,D5 ;GET DATA TO WRITE
NOT.L D2 ;MAKE NOTMASK
NXTV MOVE.L D2,D3 ;GET NOTMASK
AND.L (A4),D3 ;PUNCH A HOLE IN THE DST
OR.L D5,D3 ;COMBINE SRC AND DST
MOVE.L D3,(A4) ;AND PUT TO DST
ADD D7,A4 ;BUMP TO NEXT ROW
DBRA D1,NXTV ;LOOP ALL DOTS
BRA.S DONE ;RESTORE CURSOR AND QUIT
ALIGN Alignment
VTOGL EOR.L D2,(A4) ;TOGGLE ONE DOT
ADD D7,A4 ;BUMP TO NEXT ROW
DBRA D1,VTOGL ;LOOP ALL DOTS
BRA.S DONE ;RESTORE CURSOR AND QUIT
ALIGN Alignment
VOR OR.L D2,(A4) ;TOGGLE ONE DOT
ADD D7,A4 ;BUMP TO NEXT ROW
DBRA D1,VOR ;LOOP ALL DOTS
BRA.S DONE ;RESTORE CURSOR AND QUIT
ALIGN Alignment
VAND NOT.L D2 ;MAKE INTO CLEARING MASK
@AND AND.L D2,(A4) ;TOGGLE ONE DOT
ADD D7,A4 ;BUMP TO NEXT ROW
DBRA D1,@AND ;LOOP ALL DOTS
BRA.S DONE ;RESTORE CURSOR AND QUIT
ALIGN Alignment
;------------------------------------------------------------------------
;
; LOCAL ROUTINE TO SET UP POINTER TO FIRST WORD, BIT INDEX, AND ROWBYTES
;
; INPUTS: MINRECT
; A5: thePort
;
; OUTPUTS: D0: LEFT MOD 32 (for getting mask)
; D1: LEFT DIV 32 (for long position)
; D3: DSTSHIFT
; D7: ROWBYTES
; A4: POINTER TO FIRST WORD
;
; CLOBBERS: D0,D1,D7,A0,A4
;
HVSETUP MOVE.L DSTPIX+BASEADDR(A6),A4 ;GET BITMAP START
MOVE MINRECT+TOP(A6),D0 ;GET STARTING VERT
SUB DSTPIX+BOUNDS+TOP(A6),D0 ;CONVERT TO GLOBAL
MOVE DSTPIX+ROWBYTES(A6),D7 ;GET ROWBYTES
AND #nuRBMask,D7 ;clear off flag bits
MULS D7,D0 ;MULT TOP BY ROWBYTES; BAL 02Dec88
ADD.L D0,A4 ;ADD TO BASEADDR
MOVE MINRECT+LEFT(A6),D0 ;GET STARTING HORIZ
SUB DSTPIX+BOUNDS+LEFT(A6),D0 ;CONVERT TO GLOBAL
EXT.L D0 ;MAKE IT LONG
MOVE DSTSHIFT(A6),D3 ;GET DSTSHIFT
EXT.L D3 ;MAKE IT LONG
LSL.L D3,D0 ;CONVERT PIXELS TO BITS
MOVE.L D0,D1 ;MAKE A COPY
LSR.L #5,D1 ;CONVERT BITS TO LONGS
LEA (A4,D1*4),A4 ;add in byte cnt
AND #$1F,D0 ;TREAT LEFT MOD 32
RTS
ALIGN 4
;-------------------------------------------------------
SteepBlitTab
DC.L steepCopy1-SteepBlitTab
DC.L steepCopy2-SteepBlitTab
DC.L steepCopy4-SteepBlitTab
DC.L steepCopy8-SteepBlitTab
DC.L steepCopy16-SteepBlitTab
DC.L steepCopy32-SteepBlitTab
SteepBlitXorTab
DC.L steepXor1-SteepBlitTab
DC.L steepXor2-SteepBlitTab
DC.L steepXor4-SteepBlitTab
DC.L steepXor8-SteepBlitTab
DC.L steepXor16-SteepBlitTab
DC.L steepXor32-SteepBlitTab
;-------------------------------------------------------
ShallowBlitTab
DC.L shallowCopy1-ShallowBlitTab
DC.L shallowCopy2-ShallowBlitTab
DC.L shallowCopyN-ShallowBlitTab
DC.L shallowCopyN-ShallowBlitTab
DC.L shallowCopyN-ShallowBlitTab
DC.L done-ShallowBlitTab ;never used
ShallowBlitXorTab
DC.L shallowXor1-ShallowBlitTab
DC.L shallowXor2-ShallowBlitTab
DC.L shallowXorN-ShallowBlitTab
DC.L shallowXorN-ShallowBlitTab
DC.L shallowXorN-ShallowBlitTab
DC.L done-ShallowBlitTab ;never used
ALIGN Alignment
;-------------------------------------------------------
;
; SET UP AND DRAW A FAST SLANTED LINE.
; Only steep lines are currently implemented: (45°<=ø<=135°)
;
; Assumes: D1,D2,D3,D4 = MinRect top,left,bottom,right
; D7 = slope (16.16)
FASTSLANT
;------------------------------------------------------------------------
;
; SET UP REGISTERS FOR FAST SLANT LOOPS
;
; INPUTS: MINRECT, DSTPIX, SLOPE
;
;-------------------------------------------------------
; a0 = d0 =
; a1 = d1 = fgColor/bkColor
; a2 = d2 = dst pixel size (bit width)
; a3 = rowBytes d3 = dstShift
; a4 = dstPtr d4 = bit offset to pixel left
; a5 = d5 = leftEdge (16.16)
; a6 = locals d6 = scan count (zero based)
; a7^= d7 = slope (16.16)
;-------------------------------------------------------
; includes fix as seen in QDciPatchROM.a <sm 6/9/92>stb
SLANTSETUP
TST.B alphaMode(A6) ;if alphamode == 0, stay in all cases <6>
BEQ.S @stay ; <6>
TST A2 ;leave if shallow and alphamode != 0 <6>
BEQ goBack ; <6>
MOVE LOCMODE(A6),D0 ;get the local mode <6>
ADDQ #1,D0 ;convert from xor=1 to xor=srcXor <6>
CMP #srcXor,D0 ; <6>
BNE goBack ;if copying, leave because alphamode != 0
@stay MOVE.L DSTPIX+BASEADDR(A6),A4 ;GET BITMAP START
MOVE D1,D0 ;GET STARTING VERT
SUB DSTPIX+BOUNDS+TOP(A6),D0 ;CONVERT TO GLOBAL
MOVE DSTPIX+ROWBYTES(A6),D6 ;GET ROWBYTES
AND #nuRBMask,D6 ;clear off flag bits
MULS D6,D0 ;MULT TOP BY ROWBYTES
MOVE D6,A3 ;REMEMBER ROWBYTES
ADD.L D0,A4 ;ADD TO BASEADDR
tst.w a2 ;taller or wider?
beq Shallow
SUB D1,D3 ;CALC HEIGHT
MOVEQ #-1,D6 ;
ADD D3,D6 ;D6 IS HEIGHT-1
MOVE.L LEFTEDGE(A6),D5 ;GET LEFTEDGE
MOVE.L D5,D2 ;Get LeftEdge.int
SWAP D2
SUB DSTPIX+BOUNDS+LEFT(A6),D2 ;CONVERT TO GLOBAL
EXT.L D2 ;MAKE IT LONG
MOVE DSTSHIFT(A6),D3 ;GET DSTSHIFT
LSL.L D3,D2 ;CONVERT PIXELS TO BITS
MOVE.L D2,D4 ;MAKE A COPY
LSR.L #5,D2 ;CONVERT BITS TO LONGS
LSL.L #2,D2 ;Convert back to bytes
ADD.L D2,A4 ;ADD TO RUNNING TOTAL
AND #$1F,D4 ;TREAT LEFT MOD 32
;-----------------------------------------------------------
;
; Switch to 32 bit addressing mode
;
moveq #true32b,d0 ;switch to 32 bit addressing
_rSwapMMUMode ;(can trash a0/a1/a2, d0/d1/d2)
move.b d0,MMUsave(a6) ;save previous state for later
tst.l d7 ;are we going right to left
bpl.s @toRight ;fractions ok
neg.w d7 ;make fraction positive
not.w d5 ;measure distance from right
;(plus one for boundary cases)
@toRight
tst.w d7 ;are we ± 45°?
bne.s @not45 ;FOR REED:
not.w d7 ;hack slope and fraction so that
move.w d7,d5 ;every scanline generates a carry
@not45
MOVE DSTPIX+PIXELSIZE(A6),D2 ;GET DST PIXEL SIZE
MOVE.L FCOLOR(A6),D1 ;ASSUME FOREGROUND COLOR
moveq #0,d0 ;init zero register for loops
LEA SteepBlitTab,a0 ;point to mode table
CMP #1,LOCMODE(A6) ;WHICH MODIFIED MODE ?
BLT.S @useFG ;BR IF FOREGROUND
BEQ.S @doXor ;BR IF XOR
;ELSE BACKGROUND
MOVE.L BCOLOR(A6),D1 ;GET THE COLOR
@useFG ADD.L (A0,D3*4),A0 ;GET MODECASE
JMP (A0) ;GO THERE
@doXor MOVE.L alphaMask(A6),D1 ;get xoring mask
ADD.L SteepBlitXorTab-SteepBlitTab(A0,D3*4),A0 ;Adjusted modecase
JMP (A0) ;GO THERE
ALIGN Alignment
;-------------------------------------------------------
;
; DRAW ONE PIXEL WIDE STEEP SLANTED LINES
;
;-------------------------------------------------------
; a0 = d0 = zero
; a1 = d1 = fgColor/bkColor/(-1 for xor)
; a2 = d2 = dst pixel size (bit width)
; a3 = rowBytes d3 = dstShift
; a4 = dstPtr d4 = bit offset to pixel left
; a5 = d5 = leftEdge (16.16)
; a6 = locals d6 = scan count (zero based)
; a7^= d7 = slope (16.16)
;-------------------------------------------------------
steepCopy1
tst.l d7 ;are we backwards
bmi.s @toLeft
@toRight
bfins d1,(a4){d4:d2} ;blit one pixel
add.l a3,a4 ;bump to next row
add.w d7,d5 ;add fractions
addx.l d0,d4
dbra d6,@toRight
bra done
ALIGN Alignment
@toLeft
bfins d1,(a4){d4:d2} ;blit one pixel
add.l a3,a4 ;bump to next row
add.w d7,d5 ;add fractions
subx.l d0,d4
dbra d6,@toLeft
bra done
ALIGN Alignment
;-------------------------------------------------------
steepCopy2
tst.l d7 ;are we backwards
bmi.s @toLeft
@toRight
bfins d1,(a4){d4:2} ;blit one pixel
add.l a3,a4 ;bump to next row
move.l d0,d2 ;start with zero
add.w d7,d5 ;add fractions
addx.l d0,d2 ;get a one or zero
add.l d2,d4 ;bump a bit
add.l d2,d4 ;bump a bit
dbra d6,@toRight
bra done
ALIGN Alignment
@toLeft
bfins d1,(a4){d4:2} ;blit one pixel
add.l a3,a4 ;bump to next row
move.l d0,d2 ;start with zero
add.w d7,d5 ;add fractions
addx.l d0,d2
sub.l d2,d4 ;bump a bit
sub.l d2,d4 ;bump a bit
dbra d6,@toLeft
bra done
ALIGN Alignment
;-------------------------------------------------------
steepCopy4
tst.l d7 ;are we backwards
bmi.s @toLeft
@toRight
bfins d1,(a4){d4:4} ;blit one pixel
add.l a3,a4 ;bump to next row
move.l d0,d2 ;start with zero
add.w d7,d5 ;add fractions
addx.l d0,d2 ;get a one or zero
lsl.l #2,d2 ;scale up by bit depth
add.l d2,d4 ;bump a pixel
dbra d6,@toRight
bra done
ALIGN Alignment
@toLeft
bfins d1,(a4){d4:4} ;blit one pixel
add.l a3,a4 ;bump to next row
move.l d0,d2 ;start with zero
add.w d7,d5 ;add fractions
addx.l d0,d2
lsl.l #2,d2 ;scale up by bit depth
sub.l d2,d4 ;bump a pixel
dbra d6,@toLeft
bra done
ALIGN Alignment
;-------------------------------------------------------
steepCopy8
lsr.l #3,d4 ;convert bit offset to byte offset
tst.l d7 ;are we backwards
bmi.s @toLeft
@toRight
move.b d1,(a4,d4) ;blit one pixel
add.l a3,a4 ;bump to next row
add.w d7,d5 ;add fractions
addx.l d0,d4 ;bump a pixel
dbra d6,@toRight
bra done
ALIGN Alignment
@toLeft
move.b d1,(a4,d4) ;blit one pixel
add.l a3,a4 ;bump to next row
add.w d7,d5 ;add fractions
subx.l d0,d4
dbra d6,@toLeft
bra done
ALIGN Alignment
;-------------------------------------------------------
steepCopy16
lsr.l #4,d4 ;convert bit offset to word offset
tst.l d7 ;are we backwards
bmi.s @toLeft
@toRight
move.w d1,(a4,d4*2) ;blit one pixel
add.l a3,a4 ;bump to next row
add.w d7,d5 ;add fractions
addx.l d0,d4 ;bump a pixel
dbra d6,@toRight
bra done
ALIGN Alignment
@toLeft
move.w d1,(a4,d4*2) ;blit one pixel
add.l a3,a4 ;bump to next row
add.w d7,d5 ;add fractions
subx.l d0,d4
dbra d6,@toLeft
bra done
ALIGN Alignment
;-------------------------------------------------------
steepCopy32
lsr.l #5,d4 ;convert bit offset to long offset
tst.l d7 ;are we backwards
bmi.s @toLeft
@toRight
move.l d1,(a4,d4*4) ;blit one pixel
add.l a3,a4 ;bump to next row
add.w d7,d5 ;add fractions
addx.l d0,d4 ;bump a pixel
dbra d6,@toRight
bra done
ALIGN Alignment
@toLeft
move.l d1,(a4,d4*4) ;blit one pixel
add.l a3,a4 ;bump to next row
add.w d7,d5 ;add fractions
subx.l d0,d4
dbra d6,@toLeft
bra done
ALIGN Alignment
;-------------------------------------------------------
;
; XOR ONE PIXEL WIDE STEEP SLANTED LINES
;
;-------------------------------------------------------
steepXor1
tst.l d7 ;are we backwards
bmi.s @toLeft
@toRight
bfchg (a4){d4:d2} ;toggle one pixel
add.l a3,a4 ;bump to next row
add.w d7,d5 ;add fractions
addx.l d0,d4
dbra d6,@toRight
bra done
ALIGN Alignment
@toLeft
bfchg (a4){d4:d2} ;toggle one pixel
add.l a3,a4 ;bump to next row
add.w d7,d5 ;add fractions
subx.l d0,d4
dbra d6,@toLeft
bra done
ALIGN Alignment
;-------------------------------------------------------
steepXor2
tst.l d7 ;are we backwards
bmi.s @toLeft
@toRight
bfchg (a4){d4:2} ;toggle one pixel
add.l a3,a4 ;bump to next row
move.l d0,d2 ;start with zero
add.w d7,d5 ;add fractions
addx.l d0,d2 ;get a one or zero
add.l d2,d4 ;bump a bit
add.l d2,d4 ;bump a bit
dbra d6,@toRight
bra done
ALIGN Alignment
@toLeft
bfchg (a4){d4:2} ;toggle one pixel
add.l a3,a4 ;bump to next row
move.l d0,d2 ;start with zero
add.w d7,d5 ;add fractions
addx.l d0,d2
sub.l d2,d4 ;bump a bit
sub.l d2,d4 ;bump a bit
dbra d6,@toLeft
bra done
ALIGN Alignment
;-------------------------------------------------------
steepXor4
tst.l d7 ;are we backwards
bmi.s @toLeft
@toRight
bfchg (a4){d4:4} ;toggle one pixel
add.l a3,a4 ;bump to next row
move.l d0,d2 ;start with zero
add.w d7,d5 ;add fractions
addx.l d0,d2 ;get a one or zero
lsl.l #2,d2 ;scale up by bit depth
add.l d2,d4 ;bump a pixel
dbra d6,@toRight
bra done
ALIGN Alignment
@toLeft
bfchg (a4){d4:4} ;toggle one pixel
add.l a3,a4 ;bump to next row
move.l d0,d2 ;start with zero
add.w d7,d5 ;add fractions
addx.l d0,d2
lsl.l #2,d2 ;scale up by bit depth
sub.l d2,d4 ;bump a pixel
dbra d6,@toLeft
bra done
ALIGN Alignment
;-------------------------------------------------------
steepXor8
lsr.l #3,d4 ;convert bit offset to byte offset
tst.l d7 ;are we backwards
bmi.s @toLeft
@toRight
eor.b d1,(a4,d4) ;toggle one pixel
add.l a3,a4 ;bump to next row
add.w d7,d5 ;add fractions
addx.l d0,d4 ;bump a pixel
dbra d6,@toRight
bra done
ALIGN Alignment
@toLeft
eor.b d1,(a4,d4) ;toggle one pixel
add.l a3,a4 ;bump to next row
add.w d7,d5 ;add fractions
subx.l d0,d4
dbra d6,@toLeft
bra done
ALIGN Alignment
;-------------------------------------------------------
steepXor16
lsr.l #4,d4 ;convert bit offset to word offset
tst.l d7 ;are we backwards
bmi.s @toLeft
@toRight
eor.w d1,(a4,d4*2) ;toggle one pixel
add.l a3,a4 ;bump to next row
add.w d7,d5 ;add fractions
addx.l d0,d4 ;bump a pixel
dbra d6,@toRight
bra done
ALIGN Alignment
@toLeft
eor.w d1,(a4,d4*2) ;toggle one pixel
add.l a3,a4 ;bump to next row
add.w d7,d5 ;add fractions
subx.l d0,d4
dbra d6,@toLeft
bra done
ALIGN Alignment
;-------------------------------------------------------
steepXor32
lsr.l #5,d4 ;convert bit offset to long offset
tst.l d7 ;are we backwards
bmi.s @toLeft
@toRight
eor.l d1,(a4,d4*4) ;toggle one pixel
add.l a3,a4 ;bump to next row
add.w d7,d5 ;add fractions
addx.l d0,d4 ;bump a pixel
dbra d6,@toRight
bra done
ALIGN Alignment
@toLeft
eor.l d1,(a4,d4*4) ;toggle one pixel
add.l a3,a4 ;bump to next row
add.w d7,d5 ;add fractions
subx.l d0,d4
dbra d6,@toLeft
bra done
ALIGN Alignment
;-------------------------------------------------------
;
; DRAW ONE PIXEL WIDE Shallow SLANTED LINES
;
;-------------------------------------------------------
; a0 = d0 = actual slab width
; a1 = d1 = fgColor/bkColor/(-1 for xor)
; a2 = |dx/dy| d2 = zero
; a3 = rowBytes d3 = dstShift
; a4 = dstPtr d4 = bit offset to pixel left
; a5 = bits to right d5 = integer slab width
; a6 = locals d6 = scan count (zero based)
; a7^= d7 = (high)slope,(low)rightEdge
;-------------------------------------------------------
goBack
; move.w minRect+left(a6),d2 ;restore minRect left
; move.w minRect+right(a6),d4 ;restore minRect right
bra CalcBufLeft
Shallow
cmp.w lineRect+top(a6),d1 ;was top clipped?
bgt.s goBack ;yes, take slow case
cmp.w lineRect+bottom(a6),d3 ;is bottom clipped?
blt.s goBack ;yes, take slow case
SUB D1,D3 ;CALC HEIGHT
MOVEQ #-2,D6 ;
ADD D3,D6 ;D6 IS HEIGHT-2
move.w d2,d0 ;assume left to right
tst.l d7 ;dx/dy < 0?
bpl.s @useLeft ;yes, left to right
move.w d4,d0 ;no, MinRect.right instead
@useLeft
SUB DSTPIX+BOUNDS+LEFT(A6),D0 ;CONVERT MinRect.Left TO GLOBAL
EXT.L D0 ;MAKE IT LONG
MOVE DSTSHIFT(A6),D3 ;GET DSTSHIFT
LSL.L D3,D0 ;CONVERT PIXELS TO BITS
MOVE.L D0,D1 ;MAKE A COPY
LSR.L #5,D0 ;CONVERT BITS TO LONGS
LSL.L #2,D0 ;Convert back to bytes
ADD.L D0,A4 ;ADD TO RUNNING TOTAL
AND #$1F,D1 ;TREAT LEFT MOD 32
move.l d7,d5 ;copy slope
bpl.s @notNeg
neg.l d5 ;get |slope|
@notNeg move.l d5,a2 ;copy |slope| for later
cmp.l #$10800,d5 ;is it nearly 45°?
blt.s goBack ;yes, can't be as inaccurate as before
clr.w d5
swap d5 ;|slope|.int
lsl.l d3,d5 ;|slope|.int * pixelSize
cmp.w #32,d5 ;does max slab fit in a long?
bge.s goBack ;no, punt for now
SUB D2,D4 ;get pixel width
move.w rightEdge+2(a6),d7 ;get rightEdge.frac
LSL.L D3,D4 ;CONVERT PIXELS TO BITS
ADD D1,D4 ;D4 is bit offset to rightedge of last slab
MOVE.W D4,A5 ;save for later
MOVE.L D1,D4 ;save initial bit offset
tst.l d7 ;right to left?
bpl.s @widthOK
SUB D1,A5 ;undo the damage
SUB D1,A5 ;do it right
@widthOK
;
; Switch to 32 bit addressing mode
;
moveq #true32b,d0 ;switch to 32 bit addressing
_rSwapMMUMode ;(can trash a0/a1/a2, d0/d1/d2)
move.b d0,MMUsave(a6) ;save previous state for later
moveq #0,d0 ;compute first (clipped) slab width in d0
move.w minrect+right(a6),d0 ;get right clip
sub.w leftEdge(a6),d0 ;get initial slab width
tst.l d7 ;right to left?
bmi.s @yesNeg ;yes, all ok
move.w rightEdge(a6),d0 ;get rightEdge.int
sub.w minrect+left(a6),d0 ;get initial slab width
@yesNeg LSL.L D3,D0 ;CONVERT PIXELS TO BITS
moveq #0,d2 ;get a useful constant
MOVE.L FCOLOR(A6),D1 ;ASSUME FOREGROUND COLOR
LEA ShallowBlitTab,a0 ;point to mode table
CMP #1,LOCMODE(A6) ;WHICH MODIFIED MODE ?
BLT.S @useFG ;BR IF FOREGROUND
BEQ.S @doXor ;BR IF XOR
;ELSE BACKGROUND
MOVE.L BCOLOR(A6),D1 ;GET THE COLOR
@useFG ADD.L (A0,D3*4),A0 ;GET MODECASE
JMP (A0) ;GO THERE
@doXor ;Use alternate table
ADD.L ShallowBlitXorTab-ShallowBlitTab(A0,D3*4),A0 ;Adjusted modecase
JMP (A0) ;GO THERE
ALIGN Alignment
;-------------------------------------------------------
shallowCopy1 ;start with first clipped slab
tst.l d7 ;slope negative?
bmi.s @toLeft ;draw from right to left
@midR bfins d1,(a4){d4:d0} ;blit a slab
add.l a3,a4 ;bump to next row
add.l d0,d4 ;bump offset by slab width
move.w d5,d0 ;prime slab width with slope.int
add.w a2,d7 ;add fractions
addx.l d2,d0 ;conditionally add one
dbra d6,@midR
sub d4,a5 ;compute width of last slab
move a5,d0
bfins d1,(a4){d4:d0} ;blit last slab
bra done
ALIGN Alignment
@toLeft ;start with first clipped slab
@midL sub.l d0,d4 ;bump offset by slab width
bfins d1,(a4){d4:d0} ;blit a slab
add.l a3,a4 ;bump to next row
move.w d5,d0 ;prime slab width with slope.int
add.w a2,d7 ;add fractions
addx.l d2,d0 ;conditionally add one
dbra d6,@midL
add d4,a5 ;compute width of last slab
move a5,d0
sub.l d0,d4 ;bump offset by slab width
bfins d1,(a4){d4:d0} ;blit last slab
bra done
ALIGN Alignment
;-------------------------------------------------------
shallowCopy2 ;start with first clipped slab
tst.l d7 ;slope negative?
bmi.s @toLeft ;draw from right to left
@midR bfins d1,(a4){d4:d0} ;blit a slab
add.l a3,a4 ;bump to next row
add.l d0,d4 ;bump offset by slab width
move.l d2,d0 ;zero working register
add.w a2,d7 ;add fractions
addx.l d2,d0 ;conditionally add 1
add.l d0,d0 ;double it
add.l d5,d0 ;add in base slab width (slope.int)
dbra d6,@midR
sub d4,a5 ;compute width of last slab
move a5,d0
bfins d1,(a4){d4:d0} ;blit last slab
bra done
ALIGN Alignment
@toLeft ;start with first clipped slab
@midL sub.l d0,d4 ;bump offset by slab width
bfins d1,(a4){d4:d0} ;blit a slab
add.l a3,a4 ;bump to next row
move.l d2,d0 ;zero working register
add.w a2,d7 ;add fractions
addx.l d2,d0 ;conditionally add 1
add.l d0,d0 ;double it
add.l d5,d0 ;add in base slab width (slope.int)
dbra d6,@midL
add d4,a5 ;compute width of last slab
move a5,d0
sub.l d0,d4 ;bump offset by slab width
bfins d1,(a4){d4:d0} ;blit last slab
bra done
ALIGN Alignment
;-------------------------------------------------------
shallowCopyN ;start with first clipped slab
tst.l d7 ;slope negative?
bmi.s @toLeft ;draw from right to left
@midR bfins d1,(a4){d4:d0} ;blit a slab
add.l a3,a4 ;bump to next row
add.l d0,d4 ;bump offset by slab width
move.l d2,d0 ;zero working register
add.w a2,d7 ;add fractions
addx.l d2,d0 ;conditionally add 1
lsl.l d3,d0 ;quad it
add.l d5,d0 ;add in base slab width (slope.int)
dbra d6,@midR
sub d4,a5 ;compute width of last slab
move a5,d0
bfins d1,(a4){d4:d0} ;blit last slab
bra done
ALIGN Alignment
@toLeft ;start with first clipped slab
@midL sub.l d0,d4 ;bump offset by slab width
bfins d1,(a4){d4:d0} ;blit a slab
add.l a3,a4 ;bump to next row
move.l d2,d0 ;zero working register
add.w a2,d7 ;add fractions
addx.l d2,d0 ;conditionally add 1
lsl.l d3,d0 ;quad it
add.l d5,d0 ;add in base slab width (slope.int)
dbra d6,@midL
add d4,a5 ;compute width of last slab
move a5,d0
sub.l d0,d4 ;bump offset by slab width
bfins d1,(a4){d4:d0} ;blit last slab
bra done
ALIGN Alignment
;-------------------------------------------------------
shallowXor1 ;start with first clipped slab
tst.l d7 ;slope negative?
bmi.s @toLeft ;draw from right to left
@midR bfchg (a4){d4:d0} ;blit a slab
add.l a3,a4 ;bump to next row
add.l d0,d4 ;bump offset by slab width
move.w d5,d0 ;prime slab width with slope.int
add.w a2,d7 ;add fractions
addx.l d2,d0 ;conditionally add one
dbra d6,@midR
sub d4,a5 ;compute width of last slab
move a5,d0
bfchg (a4){d4:d0} ;blit last slab
bra done
ALIGN Alignment
@toLeft ;start with first clipped slab
@midL sub.l d0,d4 ;bump offset by slab width
bfchg (a4){d4:d0} ;blit a slab
add.l a3,a4 ;bump to next row
move.w d5,d0 ;prime slab width with slope.int
add.w a2,d7 ;add fractions
addx.l d2,d0 ;conditionally add one
dbra d6,@midL
add d4,a5 ;compute width of last slab
move a5,d0
sub.l d0,d4 ;bump offset by slab width
bfchg (a4){d4:d0} ;blit last slab
bra done
ALIGN Alignment
;-------------------------------------------------------
shallowXor2 ;start with first clipped slab
tst.l d7 ;slope negative?
bmi.s @toLeft ;draw from right to left
@midR bfchg (a4){d4:d0} ;blit a slab
add.l a3,a4 ;bump to next row
add.l d0,d4 ;bump offset by slab width
move.l d2,d0 ;zero working register
add.w a2,d7 ;add fractions
addx.l d2,d0 ;conditionally add 1
add.l d0,d0 ;double it
add.l d5,d0 ;add in base slab width (slope.int)
dbra d6,@midR
sub d4,a5 ;compute width of last slab
move a5,d0
bfchg (a4){d4:d0} ;blit last slab
bra done
ALIGN Alignment
@toLeft ;start with first clipped slab
@midL sub.l d0,d4 ;bump offset by slab width
bfchg (a4){d4:d0} ;blit a slab
add.l a3,a4 ;bump to next row
move.l d2,d0 ;zero working register
add.w a2,d7 ;add fractions
addx.l d2,d0 ;conditionally add 1
add.l d0,d0 ;double it
add.l d5,d0 ;add in base slab width (slope.int)
dbra d6,@midL
add d4,a5 ;compute width of last slab
move a5,d0
sub.l d0,d4 ;bump offset by slab width
bfchg (a4){d4:d0} ;blit last slab
bra done
ALIGN Alignment
;-------------------------------------------------------
shallowXorN ;start with first clipped slab
tst.l d7 ;slope negative?
bmi.s @toLeft ;draw from right to left
@midR bfchg (a4){d4:d0} ;blit a slab
add.l a3,a4 ;bump to next row
add.l d0,d4 ;bump offset by slab width
move.l d2,d0 ;zero working register
add.w a2,d7 ;add fractions
addx.l d2,d0 ;conditionally add 1
lsl.l d3,d0 ;quad it
add.l d5,d0 ;add in base slab width (slope.int)
dbra d6,@midR
sub d4,a5 ;compute width of last slab
move a5,d0
bfchg (a4){d4:d0} ;blit last slab
bra done
ALIGN Alignment
@toLeft ;start with first clipped slab
@midL sub.l d0,d4 ;bump offset by slab width
bfchg (a4){d4:d0} ;blit a slab
add.l a3,a4 ;bump to next row
move.l d2,d0 ;zero working register
add.w a2,d7 ;add fractions
addx.l d2,d0 ;conditionally add 1
lsl.l d3,d0 ;quad it
add.l d5,d0 ;add in base slab width (slope.int)
dbra d6,@midL
add d4,a5 ;compute width of last slab
move a5,d0
sub.l d0,d4 ;bump offset by slab width
bfchg (a4){d4:d0} ;blit last slab
bra done
;-------------------------------------------------------
ENDPROC
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