Really Useful CD 1

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Text File | 1991-05-24 | 39.4 KB | 780 lines

REM > <Graphics$Dir>.Line draw routine for 8 bpp modes REM REM Version 1.04 ⌐ Jan-Herman Buining (24-May-1991) REM REM For one byte per pixel screen modes only REM : REM Screen mode, boundaries, size and resolution MODE 13 : REM Screen mode XShift=2 : REM X pixel shift factor YShift=2 : REM Y pixel shift factor HSize =1280 : REM Screen width in pixels (bytes) VSize =1024 : REM Screen height in pixels (bytes) LBound=0 +320 : REM Minimum X >= 0 RBound=1280-320 : REM Maximum X+1 <= HSize BBound=0 +256 : REM Minimum Y >= 0 TBound=1024-256 : REM Maximum Y+1 <= VSize : REM Random generator coords resolution in bits Random=11 : REM -1024 <= Random <= 1023 : REM Bounding box, lines should clip inside this RECTANGLE LBound-1,BBound-1,RBound-LBound+1,TBound-BBound+1 VDU 24,LBound;BBound;RBound-1;TBound-1; : PROCAssemble(Start%,End%) : REM Repeated drawing of random lines until <Escape> CALL CallLine : END : DEF PROCLine(A%,B%,C%,D%,E%) CALL Line ENDPROC : REM +++++ ASSEMBLY +++++ : DEF PROCAssemble(RETURN Code%,RETURN O%) LOCAL Opt%,L%,P%,CodeSize% : REM Size of code CodeSize=4<<10 : DIM Code% CodeSize,L% -1 : FOR Opt%=%1100 TO %1110 STEP %0010 P%=Code% O%=Code% [OPT Opt% ;********************************************** ;********************************************** ;** Data ** ;********************************************** ;********************************************** .ScreenAddress EQUD FNScreenAddress ; Screen base address ; Optionally you could choose to store window ; clipping (bound) variables in this block ;---------------------------------------------- .RandomSeed1 EQUD RND(TIME) ; Random seed .RandomSeed2 EQUD RND(2) ; 33rd bit ;********************************************** ;********************************************** ;** Random coordinates ** ;********************************************** ;********************************************** .RandomCoordinates STMFD R13!,{R8-R10,R14} LDR R8,RandomSeed1 LDR R9,RandomSeed2 ;---------------------------------------------- TST R9,R9,LSR #1 ; Fast random number MOVS R10,R8,RRX ADC R9,R9,R9 EOR R10,R10,R8,LSL #12 EOR R8,R10,R10,LSR #20 ; Random mumber in R8 MOV R0,R8 ;---------------------------------------------- TST R9,R9,LSR #1 ; Fast random number MOVS R10,R8,RRX ADC R9,R9,R9 EOR R10,R10,R8,LSL #12 EOR R8,R10,R10,LSR #20 ; Random mumber in R8 MOV R1,R8 ;---------------------------------------------- TST R9,R9,LSR #1 ; Fast random number MOVS R10,R8,RRX ADC R9,R9,R9 EOR R10,R10,R8,LSL #12 EOR R8,R10,R10,LSR #20 ; Random mumber in R8 MOV R2,R8 ;---------------------------------------------- TST R9,R9,LSR #1 ; Fast random number MOVS R10,R8,RRX ADC R9,R9,R9 EOR R10,R10,R8,LSL #12 EOR R8,R10,R10,LSR #20 ; Random mumber in R8 MOV R3,R8 ;---------------------------------------------- TST R9,R9,LSR #1 ; Fast random number MOVS R10,R8,RRX ADC R9,R9,R9 EOR R10,R10,R8,LSL #12 EOR R8,R10,R10,LSR #20 ; Random mumber in R8 MOV R4,R8,LSR #24 ; Colour ;---------------------------------------------- STR R8,RandomSeed1 STR R9,RandomSeed2 ;---------------------------------------------- MOV R8,#LBound ; Centre random coordinates ADD R8,R8,#RBound ; for neater display MOV R8,R8,ASR #1 ; Window X centre MOV R9,#BBound ADD R9,R9,#TBound MOV R9,R9,ASR #1 ; Window Y centre MOV R0,R0,LSR #32-Random ; X1 SUB R0,R0,#1<<(Random-1) ADD R0,R0,R8 MOV R1,R1,LSR #32-Random ; Y1 SUB R1,R1,#1<<(Random-1) ADD R1,R1,R9 MOV R2,R2,LSR #32-Random ; X2 SUB R2,R2,#1<<(Random-1) ADD R2,R2,R8 MOV R3,R3,LSR #32-Random ; Y2 SUB R3,R3,#1<<(Random-1) ADD R3,R3,R9 LDMFD R13!,{R8-R10,PC}^ ; {R0=X start point} ; {R1=Y start point} ; {R2=X end point} ; {R3=Y end point} ; {R4=Colour byte} ;********************************************** .CallLine STMFD R13!,{R0-R5,R14} SWI "XOS_RemoveCursors" .CallLineCont MOV R5,#256 ; 256 lines at a time .CallLineNext BL RandomCoordinates ; Get random point and colour BL Line ; Plot the line SUBS R5,R5,#1 ; Next line BGT CallLineNext SWI "XOS_ReadEscapeState" BCC CallLineCont ; Next 256 lines SWI "XOS_RestoreCursors" LDMFD R13!,{R0-R5,PC}^ ; Preserve mode and state ;********************************************** ;********************************************** ;** Line preprocessing ** ;********************************************** ;********************************************** ; {R0=X start point} ; {R1=Y start point} ; {R2=X end point} ; {R3=Y end point} ; {R4=Colour byte} ; {Preserve mode and state} .Line STMFD R13!,{R0-R6,R11,R14} MOV R0,R0,LSL #16 ; Ensure 16 bit coords MOV R1,R1,LSL #16 ; Don't combine these two MOV R2,R2,LSL #16 ; shifts as line rejection MOV R3,R3,LSL #16 ; compatibility will be lost MOV R0,R0,ASR #XShift ; Shift to screen resolution MOV R1,R1,ASR #XShift MOV R2,R2,ASR #XShift MOV R3,R3,ASR #XShift ;---------------------------------------------- CMP R3,R1 ; Delta Y BEQ LineHorizontal ; Line is horizontal or point CMP R2,R0 ; Delta X BEQ LineVertical ; Line is vertical BGT LinePreprocess ; Coordinates in right order ;---------------------------------------------- EOR R0,R0,R2 ; Swap X coordinates EOR R2,R0,R2 EOR R0,R0,R2 EOR R1,R1,R3 ; Swap Y coordinates also EOR R3,R1,R3 EOR R1,R1,R3 ;---------------------------------------------- .LinePreprocess MOV R5,#0 ; Point state CMP R0,#LBound<<16-XShift ORRLT R5,R5,#%0001 ; Left of border CMP R0,#RBound<<16-XShift ORRGE R5,R5,#%0010 ; Right of border CMP R1,#BBound<<16-YShift ORRLT R5,R5,#%0100 ; Below border CMP R1,#TBound<<16-YShift ORRGE R5,R5,#%1000 ; Above border ;---------------------------------------------- MOV R6,#0 ; Point state CMP R2,#LBound<<16-XShift ORRLT R6,R6,#%0001 ; Left of border CMP R2,#RBound<<16-XShift ORRGE R6,R6,#%0010 ; Right of border CMP R3,#BBound<<16-YShift ORRLT R6,R6,#%0100 ; Below border CMP R3,#TBound<<16-YShift ORRGE R6,R6,#%1000 ; Above border ;---------------------------------------------- ORRS R11,R5,R6 ; Combination BEQ LineOnScreen ; Line already on screen EOR R14,R5,R6 ; Difference BICS R14,R11,R14 ; Logical intersection LDMNEFD R13!,{R0-R6,R11,PC}^ ; Line outside boundaries TST R11,#%0011 ; Actually, this can only be BNE LineClipToX ; called first (or never) ;---------------------------------------------- .LineClipToY STMFD R13!,{R7-R10} ; {R5,R6,R11,R14 Corruptable} MOV R7,R2,ASR #1 ; Dx was positive SUB R7,R7,R0,ASR #1 ; Subdivide X MOV R8,R3,ASR #1 ; Dy can be anything SUBS R8,R8,R1,ASR #1 ; Subdivide Y BEQ LineClipToYExit ; No more clipping possible RSBLT R8,R8,#0 ; Dy must be positive RSBLT R7,R7,#0 ; Negate Dx ;---------------------------------------------- MOV R9,#BBound>>YShift ; Screen Y boundary (bottom) MOV R10,#TBound>>YShift ; Screen Y boundary (top) SUB R10,R10,#1 ; Visible boundary ;---------------------------------------------- .LineClipToYNext TST R5,#%0100 ; Clip to line Y=R9 ? BEQ LineClipToYNBY1 ; No CMP R1,R9,LSL #16 ; Position from clipping line ADDLT R0,R0,R7 ; Under ADDLT R1,R1,R8 SUBGE R0,R0,R7 ; Over SUBGE R1,R1,R8 CMP R9,R1,ASR #16 ; Am I on the clipping line ? BICEQ R5,R5,#%0100 ; Yes B LineClipToYNTY1 ; Mutual exclusive ;---------------------------------------------- .LineClipToYNBY1 TST R5,#%1000 ; Clip to line Y=R10 ? BEQ LineClipToYNTY1 ; No CMP R1,R10,LSL #16 ; Position from clipping line ADDLT R0,R0,R7 ; Under ADDLT R1,R1,R8 SUBGE R0,R0,R7 ; Over SUBGE R1,R1,R8 CMP R10,R1,ASR #16 ; Am I on the clipping line ? BICEQ R5,R5,#%1000 ; Yes ;---------------------------------------------- .LineClipToYNTY1 TST R6,#%0100 ; Clip to line Y=R9 ? BEQ LineClipToYNBY2 ; No CMP R3,R9,LSL #16 ; Position from clipping line ADDLT R2,R2,R7 ; Under ADDLT R3,R3,R8 SUBGE R2,R2,R7 ; Over SUBGE R3,R3,R8 CMP R9,R3,ASR #16 ; Am I on the clipping line ? BICEQ R6,R6,#%0100 ; Yes B LineClipToYNTY2 ; Mutual exclusive ;---------------------------------------------- .LineClipToYNBY2 TST R6,#%1000 ; Clip to line Y=R10 ? BEQ LineClipToYNTY2 ; No CMP R3,R10,LSL #16 ; Position from clipping line ADDLT R2,R2,R7 ; Under ADDLT R3,R3,R8 SUBGE R2,R2,R7 ; Over SUBGE R3,R3,R8 CMP R10,R3,ASR #16 ; On the clipping line ? BICEQ R6,R6,#%1000 ; Yes ;---------------------------------------------- .LineClipToYNTY2 MOVS R8,R8,ASR #1 ; Subdivide Y BEQ LineClipToYExit ; No more clipping possible MOV R7,R7,ASR #1 ; Subdivide X ;---------------------------------------------- ORR R11,R5,R6 ; Combination ANDS R11,R11,#%1100 ; Y clipping done ? BNE LineClipToYNext ; No ;---------------------------------------------- .LineClipToYExit CMP R0,#LBound<<16-XShift; Round off error ? MOVLT R0,#LBound<<16-XShift; Yes CMP R1,#BBound<<16-YShift MOVLT R1,#BBound<<16-YShift CMP R2,#LBound<<16-XShift MOVLT R2,#LBound<<16-XShift CMP R3,#BBound<<16-YShift MOVLT R3,#BBound<<16-YShift LDMFD R13!,{R7-R10} ;---------------------------------------------- MOV R5,R3,ASR #16 CMP R5,R1,ASR #16 ; Delta Y BEQ LineHorizontal ; Line is horizontal or point MOV R5,R2,ASR #16 CMP R5,R0,ASR #16 ; Delta X BEQ LineVertical ; Line is vertical ;---------------------------------------------- .LineOnScreen MOV R0,R0,ASR #16 ; Hardware coords MOV R1,R1,ASR #16 MOV R2,R2,ASR #16 MOV R3,R3,ASR #16 ;---------------------------------------------- SUB R2,R2,R0 ; Delta X MOV R5,#(HSize>>XShift) ; Pixels per line SUBS R3,R3,R1 ; Delta Y RSBLT R3,R3,#0 ; Absolute value of Delta Y RSBGT R5,R5,#0 ; Ascending, is down in memory FNPixelAddress ; Returns pixel address in R11 ;---------------------------------------------- CMP R2,R3 BGT LineAroundHorizontal BLT LineAroundVertical BEQ LineDiagonal ;********************************************** ;********************************************** ;** Horizontal clipping ** ;********************************************** ;********************************************** .LineClipToX STMFD R13!,{R7-R10} ; {R5,R6,R11,R14 Corruptable} MOV R8,R3,ASR #1 ; Dy can be anything SUB R8,R8,R1,ASR #1 ; Subdivide Y MOV R7,R2,ASR #1 ; Dx was positive SUBS R7,R7,R0,ASR #1 ; Subdivide X BEQ LineClipToXExit ; No more clipping possible ;---------------------------------------------- MOV R9,#LBound>>XShift ; Screen X boundary (left) MOV R10,#RBound>>XShift ; Screen X boundary (right) SUB R10,R10,#1 ; Visible boundary ;---------------------------------------------- .LineClipToXNext TST R5,#%0001 ; Clip to line X=R9 ? BEQ LineClipToXNLX1 ; No CMP R0,R9,LSL #16 ; Position from clipping line ADDLT R0,R0,R7 ; Left ADDLT R1,R1,R8 SUBGE R0,R0,R7 ; Right SUBGE R1,R1,R8 CMP R9,R0,ASR #16 ; Am I on the clipping line ? BICEQ R5,R5,#%0001 ; Yes B LineClipToXNRX1 ; Mutual exclusive ;---------------------------------------------- .LineClipToXNLX1 TST R5,#%0010 ; Clip to line X=R10 ? BEQ LineClipToXNRX1 ; No CMP R0,R10,LSL #16 ; Position from clipping line ADDLT R0,R0,R7 ; Left ADDLT R1,R1,R8 SUBGE R0,R0,R7 ; Right SUBGE R1,R1,R8 CMP R10,R0,ASR #16 ; Am I on the clipping line ? BICEQ R5,R5,#%0010 ; Yes ;---------------------------------------------- .LineClipToXNRX1 TST R6,#%0001 ; Clip to line X=R9 ? BEQ LineClipToXNLX2 ; No CMP R2,R9,LSL #16 ; Position from clipping line ADDLT R2,R2,R7 ; Left ADDLT R3,R3,R8 SUBGE R2,R2,R7 ; Right SUBGE R3,R3,R8 CMP R9,R2,ASR #16 ; Am I on the clipping line ? BICEQ R6,R6,#%0001 ; Yes B LineClipToXNRX2 ; Mutual exclusive ;---------------------------------------------- .LineClipToXNLX2 TST R6,#%0010 ; Clip to line X=R10 ? BEQ LineClipToXNRX2 ; No CMP R2,R10,LSL #16 ; Position from clipping line ADDLT R2,R2,R7 ; Left ADDLT R3,R3,R8 SUBGE R2,R2,R7 ; Right SUBGE R3,R3,R8 CMP R10,R2,ASR #16 ; On the clipping line ? BICEQ R6,R6,#%0010 ; Yes ;---------------------------------------------- .LineClipToXNRX2 MOVS R7,R7,ASR #1 ; Subdivide X BEQ LineClipToXExit ; No more clipping possible MOV R8,R8,ASR #1 ; Subdivide Y ;---------------------------------------------- ORR R11,R5,R6 ; Combination ANDS R11,R11,#%0011 ; X clipping done ? BNE LineClipToXNext ; No ;---------------------------------------------- .LineClipToXExit CMP R0,#LBound<<16-XShift; Round off error ? MOVLT R0,#LBound<<16-XShift; Yes LDMFD R13!,{R7-R10} ;---------------------------------------------- MOV R5,R3,ASR #16 CMP R5,R1,ASR #16 ; Delta Y BEQ LineHorizontal ; Line is horizontal or point MOV R5,R2,ASR #16 CMP R5,R0,ASR #16 ; Delta X BEQ LineVertical ; Line is vertical B LinePreprocess ; Now clip, reject or draw ;********************************************** ;********************************************** ;** Horizontal line drawing ** ;********************************************** ;********************************************** ; {R0=X start point <<16} ; {R1=Y start point <<16} ; {R2=X end point <<16} ; {R3=Y end point <<16} ; {R4=Colour byte} .LineHorizontal CMP R1,#BBound<<16-YShift; Line below border ? LDMLTFD R13!,{R0-R6,R11,PC}^ CMP R1,#TBound<<16-YShift; Line above border ? LDMGEFD R13!,{R0-R6,R11,PC}^ ;---------------------------------------------- CMP R2,R0 ; X coordinates order EORLT R0,R0,R2 ; Swap X coordinates EORLT R2,R0,R2 EORLT R0,R0,R2 ;---------------------------------------------- CMP R2,#LBound<<16-XShift; Line left of border ? LDMLTFD R13!,{R0-R6,R11,PC}^ CMP R0,#RBound<<16-XShift; Line right of border ? LDMGEFD R13!,{R0-R6,R11,PC}^ ;---------------------------------------------- MOV R0,R0,ASR #16 ; Hardware coords MOV R1,R1,ASR #16 MOV R2,R2,ASR #16 MOV R3,R3,ASR #16 ;---------------------------------------------- CMP R0,#LBound>>XShift ; Clip X start ? MOVLT R0,#LBound>>XShift CMP R2,#RBound>>XShift ; Clip X end ? MOVGE R2,#RBound>>XShift ; One too high therefore ADDLT SUB R2,R2,R0 ; Delta X, one too low ADDLT R2,R2,#1 ; Number of pixels to plot FNPixelAddress ; Returns pixel address in R11 ;---------------------------------------------- RSBS R5,R2,#11 ; Short lines breakeven point ADDGE PC,PC,R5,LSL #2 ; 1*4 bytes of code B LineHorizontalLong ; 12 or more pixels STRB R4,[R11],#1 ; 11 pixels STRB R4,[R11],#1 STRB R4,[R11],#1 STRB R4,[R11],#1 ; 8 pixels STRB R4,[R11],#1 STRB R4,[R11],#1 STRB R4,[R11],#1 STRB R4,[R11],#1 ; 4 pixels STRB R4,[R11],#1 STRB R4,[R11],#1 STRB R4,[R11],#1 ; 1 pixel LDMFD R13!,{R0-R6,R11,PC}^ ;---------------------------------------------- .LineHorizontalLong ANDS R5,R11,#%11 ; Bytes before aligned part BEQ LineHorizontalAligned RSB R5,R5,#4 ; Bytes to plot to align CMP R5,#2 STRGTB R4,[R11],#1 ; 3 pixels STRGEB R4,[R11],#1 ; 2 pixels STRALB R4,[R11],#1 ; 1 pixel SUBS R2,R2,R5 ; Pixels left to be plotted LDMLEFD R13!,{R0-R6,R11,PC}^ ; All pixels done ;---------------------------------------------- .LineHorizontalAligned AND R4,R4,#&FF ; Colour byte ORR R4,R4,R4,LSL #8 ; Set up colour byte to ORR R4,R4,R4,LSL #16 ; become colour word MOV R0,R4 ; For multiple stores MOV R1,R4 ; R0,R1,R3,R4 MOV R3,R4 ;---------------------------------------------- MOV R5,R2,LSR #4 ; 16 or more pixels to plot ? MOV R14,R5,LSR #5 ; 512 pixels a time AND R5,R5,#%11111 ; Multiple of 512 pixels RSB R5,R5,#32 ; Number of entries to skip ADD PC,PC,R5,LSL #2 ; 1*4 bytes of code MOVNV R0,R0 ; Dummy instruction .LineHorizontalAlignedNext512 STMIA R11!,{R0,R1,R3,R4} ; 16 MPixels/sec store STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} STMIA R11!,{R0,R1,R3,R4} SUBS R14,R14,#1 BGE LineHorizontalAlignedNext512 ;---------------------------------------------- AND R2,R2,#%1111 ; Modulo of 16 pixels MOVS R5,R2,LSR #2 ; Multiple of 4 pixels left ? BEQ LineHorizontalLessThan4 CMP R5,#2 STMGTIA R11!,{R0,R1,R3} ; 12-15 pixels STMEQIA R11!,{R0,R1} ; 8-11 pixels STMLTIA R11!,{R0} ; 4- 7 pixels ;---------------------------------------------- .LineHorizontalLessThan4 ; 0- 3 pixels ANDS R5,R2,#%11 ; Some pixels left ? LDMEQFD R13!,{R0-R6,R11,PC}^ ; No CMP R5,#2 STRGTB R4,[R11],#1 ; 3 pixels STRGEB R4,[R11],#1 ; 2 pixels STRALB R4,[R11],#1 ; 1 pixel LDMFD R13!,{R0-R6,R11,PC}^ ;********************************************** ;********************************************** ;** Vertical line drawing ** ;********************************************** ;********************************************** ; {R0=X start point <<16} ; {R1=Y start point <<16} ; {R2=X end point <<16} ; {R3=Y end point <<16} ; {R4=Colour byte} .LineVertical CMP R0,#LBound<<16-XShift; Line left of border ? LDMLTFD R13!,{R0-R6,R11,PC}^ CMP R0,#RBound<<16-XShift; Line right of border ? LDMGEFD R13!,{R0-R6,R11,PC}^ ;---------------------------------------------- CMP R1,R3 ; Y coordinates order EORLT R1,R1,R3 ; Swap Y coordinates EORLT R3,R1,R3 EORLT R1,R1,R3 ;---------------------------------------------- CMP R1,#BBound<<16-YShift; Line below border ? LDMLTFD R13!,{R0-R6,R11,PC}^ CMP R3,#TBound<<16-YShift; Line above border ? LDMGEFD R13!,{R0-R6,R11,PC}^ ;---------------------------------------------- MOV R0,R0,ASR #16 ; Hardware coords MOV R1,R1,ASR #16 MOV R2,R2,ASR #16 MOV R3,R3,ASR #16 ;---------------------------------------------- CMP R1,#TBound>>YShift ; Clip Y start ? MOVGE R1,#TBound>>YShift SUBGE R1,R1,#1 CMP R3,#BBound>>YShift ; Clip Y end ? MOVLT R3,#BBound>>YShift SUB R3,R1,R3 ; Delta Y ADD R3,R3,#1 ; Number of pixels to plot FNPixelAddress ; Returns pixel address in R11 ;---------------------------------------------- MOV R14,R3,LSR #3 ; Initialise pixel counter AND R1,R3,#%111 ; Low bits for unfold RSB R1,R1,#8 ; Skip MOD 8 entries in table ADD PC,PC,R1,LSL #2 ; 1*4 bytes of code MOVNV R0,R0 ; Dummy instruction .LineVerticalNextPixel ; 1.75 MPixels/sec store ;---------------------------------------------- STRB R4,[R11],#(HSize>>XShift) STRB R4,[R11],#(HSize>>XShift) STRB R4,[R11],#(HSize>>XShift) STRB R4,[R11],#(HSize>>XShift) STRB R4,[R11],#(HSize>>XShift) STRB R4,[R11],#(HSize>>XShift) STRB R4,[R11],#(HSize>>XShift) STRB R4,[R11],#(HSize>>XShift) SUBS R14,R14,#1 ; 8 more pixels to plot? BGE LineVerticalNextPixel LDMFD R13!,{R0-R6,R11,PC}^ ;********************************************** ;********************************************** ;** Random line drawing ** ;********************************************** ;********************************************** ; {R2=Delta X > 0 (DX>DY)} ; {R3=Delta Y > 0} ; {R4=Colour byte} ; {R5=Y screen line increment} ; {R11=Pixel base address} .LineAroundHorizontal RSB R0,R2,#0 ; Initialise error term MOV R14,R2,LSR #3 ; Initialise pixel counter AND R1,R2,#%111 ; Low bits for unfold RSB R1,R1,#8 ; Skip MOD 8 entries in table ADD PC,PC,R1,LSL #4 ; 4*4 bytes of code MOVNV R0,R0 ; Dummy instruction .LineAroundHorizontalNextPixel ; 1 MPixels/sec store ;---------------------------------------------- STRB R4,[R11],#1 ; Plot pixel and update X coord ADDS R0,R0,R3,LSL #1 ; Increase error term ADDGT R11,R11,R5 ; Update Y coord SUBGT R0,R0,R2,LSL #1 ; And decrease error term ;---------------------------------------------- STRB R4,[R11],#1 ; Plot pixel and update X coord ADDS R0,R0,R3,LSL #1 ; Increase error term ADDGT R11,R11,R5 ; Update Y coord SUBGT R0,R0,R2,LSL #1 ; And decrease error term ;---------------------------------------------- STRB R4,[R11],#1 ; Plot pixel and update X coord ADDS R0,R0,R3,LSL #1 ; Increase error term ADDGT R11,R11,R5 ; Update Y coord SUBGT R0,R0,R2,LSL #1 ; And decrease error term ;---------------------------------------------- STRB R4,[R11],#1 ; Plot pixel and update X coord ADDS R0,R0,R3,LSL #1 ; Increase error term ADDGT R11,R11,R5 ; Update Y coord SUBGT R0,R0,R2,LSL #1 ; And decrease error term ;---------------------------------------------- STRB R4,[R11],#1 ; Plot pixel and update X coord ADDS R0,R0,R3,LSL #1 ; Increase error term ADDGT R11,R11,R5 ; Update Y coord SUBGT R0,R0,R2,LSL #1 ; And decrease error term ;---------------------------------------------- STRB R4,[R11],#1 ; Plot pixel and update X coord ADDS R0,R0,R3,LSL #1 ; Increase error term ADDGT R11,R11,R5 ; Update Y coord SUBGT R0,R0,R2,LSL #1 ; And decrease error term ;---------------------------------------------- STRB R4,[R11],#1 ; Plot pixel and update X coord ADDS R0,R0,R3,LSL #1 ; Increase error term ADDGT R11,R11,R5 ; Update Y coord SUBGT R0,R0,R2,LSL #1 ; And decrease error term ;---------------------------------------------- STRB R4,[R11],#1 ; Plot pixel and update X coord ADDS R0,R0,R3,LSL #1 ; Increase error term ADDGT R11,R11,R5 ; Update Y coord SUBGT R0,R0,R2,LSL #1 ; And decrease error term ;---------------------------------------------- SUBS R14,R14,#1 ; 8 more pixels to plot? BGE LineAroundHorizontalNextPixel ;---------------------------------------------- STRB R4,[R11],#1 ; End pixel LDMFD R13!,{R0-R6,R11,PC}^ ;********************************************** ; {R2=Delta X > 0 (DX<DY)} ; {R3=Delta Y > 0} ; {R4=Colour byte} ; {R5=Y screen line increment} ; {R11=Pixel base address} .LineAroundVertical RSB R0,R3,#0 ; Initialise error term MOV R14,R3,LSR #3 ; Initialise pixel counter AND R1,R3,#%111 ; Low bits for unfold RSB R1,R1,#8 ; Skip MOD 8 entries in table ADD PC,PC,R1,LSL #4 ; 4*4 bytes of code MOVNV R0,R0 ; Dummy instruction .LineAroundVerticalNextPixel ; 1.75 MPixels/sec store ;---------------------------------------------- STRB R4,[R11],R5 ; Plot pixel and update Y coord ADDS R0,R0,R2,LSL #1 ; Increase error term ADDGT R11,R11,#1 ; Update X coord SUBGT R0,R0,R3,LSL #1 ; And decrease error term ;---------------------------------------------- STRB R4,[R11],R5 ; Plot pixel and update Y coord ADDS R0,R0,R2,LSL #1 ; Increase error term ADDGT R11,R11,#1 ; Update X coord SUBGT R0,R0,R3,LSL #1 ; And decrease error term ;---------------------------------------------- STRB R4,[R11],R5 ; Plot pixel and update Y coord ADDS R0,R0,R2,LSL #1 ; Increase error term ADDGT R11,R11,#1 ; Update X coord SUBGT R0,R0,R3,LSL #1 ; And decrease error term ;---------------------------------------------- STRB R4,[R11],R5 ; Plot pixel and update Y coord ADDS R0,R0,R2,LSL #1 ; Increase error term ADDGT R11,R11,#1 ; Update X coord SUBGT R0,R0,R3,LSL #1 ; And decrease error term ;---------------------------------------------- STRB R4,[R11],R5 ; Plot pixel and update Y coord ADDS R0,R0,R2,LSL #1 ; Increase error term ADDGT R11,R11,#1 ; Update X coord SUBGT R0,R0,R3,LSL #1 ; And decrease error term ;---------------------------------------------- STRB R4,[R11],R5 ; Plot pixel and update Y coord ADDS R0,R0,R2,LSL #1 ; Increase error term ADDGT R11,R11,#1 ; Update X coord SUBGT R0,R0,R3,LSL #1 ; And decrease error term ;---------------------------------------------- STRB R4,[R11],R5 ; Plot pixel and update Y coord ADDS R0,R0,R2,LSL #1 ; Increase error term ADDGT R11,R11,#1 ; Update X coord SUBGT R0,R0,R3,LSL #1 ; And decrease error term ;---------------------------------------------- STRB R4,[R11],R5 ; Plot pixel and update Y coord ADDS R0,R0,R2,LSL #1 ; Increase error term ADDGT R11,R11,#1 ; Update X coord SUBGT R0,R0,R3,LSL #1 ; And decrease error term ;---------------------------------------------- SUBS R14,R14,#1 ; 8 more pixels to plot? BGE LineAroundVerticalNextPixel ;---------------------------------------------- STRB R4,[R11],R5 ; End pixel LDMFD R13!,{R0-R6,R11,PC}^ ;********************************************** ; {R2=Delta X > 0 (DX=DY)} ; {R3=Delta Y > 0} ; {R4=Colour byte} ; {R5=Y screen line increment} ; {R11=Pixel base address} .LineDiagonal ADD R5,R5,#1 ; Automatic X increment ADD R3,R3,#1 ; Increment for last pixel MOV R14,R3,LSR #3 ; Initialise pixel counter AND R1,R3,#%111 ; Low bits for unfold RSB R1,R1,#8 ; Skip MOD 8 entries in table ADD PC,PC,R1,LSL #2 ; 1*4 bytes of code MOVNV R0,R0 ; Dummy instruction .LineDiagonalNextPixel ; 1.75 MPixels/sec store ;---------------------------------------------- STRB R4,[R11],R5 ; Plot pixel asn update coords STRB R4,[R11],R5 STRB R4,[R11],R5 STRB R4,[R11],R5 STRB R4,[R11],R5 STRB R4,[R11],R5 STRB R4,[R11],R5 STRB R4,[R11],R5 ;---------------------------------------------- SUBS R14,R14,#1 ; 8 more pixels to plot? BGE LineDiagonalNextPixel LDMFD R13!,{R0-R6,R11,PC}^ ;********************************************** ;********************************************** ;** End ** ;********************************************** ;********************************************** ] NEXT ENDPROC : REM ----- ASSEMBLY ----- : REM +++++ MACRO'S +++++ : DEF FNPixelAddress REM Returns the screen address for a REM pixel with (R0,R1) coordinates in R11 [OPT Opt% LDR R11,ScreenAddress ; Screen base address ADD R11,R11,R0 ; X coordinate RSB R1,R1,#(VSize>>YShift) ; Reverse Y coordinate SUB R1,R1,#1 ; to visible area maximum MOV R0,#(HSize>>XShift) ; Just this way for overscan MLA R11,R0,R1,R11 ; Address of Y coordinate line ] =Opt% : DEF FNScreenAddress DIM Block% 16 Block%!00=149 Block%!04=-1 SYS "OS_ReadVduVariables",Block%,Block%+8 =Block%!08 : DEF FNADR(R%,Label%) REM Prevents bad immediate constant problems REM Limited to addresses in the range REM -&7FFF to &7FFF relative to the PC LOCAL Move% IF (Opt% AND %10)=0 THEN [OPT Opt% EQUD 0 EQUD 0 ] ELSE Move%=Label%-(P%+8) IF Move%<0 THEN [OPT Opt% SUB R%,PC,#(-Move% AND &00FF) SUB R%,R%,#(-Move% AND &FF00) ] ELSE [OPT Opt% ADD R%,PC,#(Move% AND &00FF) ADD R%,R%,#(Move% AND &FF00) ] ENDIF ENDIF =Opt% : REM ----- MACRO'S ----- :