************************************************************************* * * * OSWORD 9 - READ A PIXEL * * =POINT(X,Y) * * * ************************************************************************* ;on entry &EF=A=9 ; &F0=X=low byte of parameter block address ; &F1=Y=high byte of parameter block address ; PARAMETER BLOCK ; 0,1=X coordinate ; 2,3=Y coordinate ;on exit, result in BLOCK+4 ; =&FF if point was off screen or logical colour of point if on screen ; C735 LDY #&03 ;Y=3 to point to hi byte of Y coordinate C737 LDA (&F0),Y ;get it C739 STA &0328,Y ;store it C73C DEY ;point to next byte C73D BPL &C737 ;transfer till Y=&FF lo byte of X coordinate in &328 C73F LDA #&28 ; C741 JSR &D839 ;check window boundaries C744 LDY #&04 ;Y=4 C746 BNE &C750 ;jump to C750 ************************************************************************* * * * OSWORD 11 - READ PALLETTE * * * ************************************************************************* ;on entry &EF=A=11 ; &F0=X=low byte of parameter block address ; &F1=Y=high byte of parameter block address ; PARAMETER BLOCK ; 0=logical colour to read ;on exit, result in BLOCK ; 0=logical colour ; 1=physical colour ; 2=red colour component \ ; 3=green colour component } when set using analogue colours ; 4=blue colour component / C748 AND &0360 ;number of logical colours less 1 C74B TAX ;put it in X C74C LDA &036F,X ;colour pallette C74F INY ;increment Y to point to byte 1 C750 STA (&F0),Y ;store data C752 LDA #&00 ;issue 0s C754 CPY #&04 ;to next bytes until Y=4 C756 BNE &C74F ; C758 RTS ;and exit ************************************************************************* * * * VDU 12 - CLEAR TEXT SCREEN * * CLS * * * ************************************************************************* ; C759 JSR &C588 ;A=0 if text cursor A=&20 if graphics cursor C75C BNE &C7BD ;if graphics cursor &C7BD C75E LDA &D0 ;VDU status byte C760 AND #&08 ;check if software scrolling (text window set) C762 BNE &C767 ;if so C767 C764 JMP &CBC1 ;initialise screen display and home cursor C767 LDX &030B ;top of text window C76A STX &0319 ;current text line C76D JSR &CEAC ;clear a line C770 LDX &0319 ;current text line C773 CPX &0309 ;bottom margin C776 INX ;X=X+1 C777 BCC &C76A ;if X at compare is less than bottom margin clear next ************************************************************************* * * * VDU 30 - HOME CURSOR * * * ************************************************************************* C779 JSR &C588 ;A=0 if text cursor A=&20 if graphics cursor C77C BEQ &C781 ;if text cursor C781 C77E JMP &CFA6 ;home graphic cursor if graphic C781 STA &0323 ;store 0 in last two parameters C784 STA &0322 ; ************************************************************************* * * * VDU 31 - POSITION TEXT CURSOR * * TAB(X,Y) * * * * 2 parameters * * * ************************************************************************* ;0322 = supplied X coordinate ;0323 = supplied Y coordinate C787 JSR &C588 ;A=0 if text cursor A=&20 if graphics cursor C78A BNE &C758 ;exit C78C JSR &C7A8 ;exchange text column/line with workspace 0328/9 C78F CLC ;clear carry C790 LDA &0322 ;get X coordinate C793 ADC &0308 ;add to text window left C796 STA &0318 ;store as text column C799 LDA &0323 ;get Y coordinate C79C CLC ; C79D ADC &030B ;add top of text window C7A0 STA &0319 ;current text line C7A3 JSR &CEE8 ;set up screen address C7A6 BCC &C732 ;set cursor position if C=0 (point on screen) C7A8 LDX #&18 ;else point to workspace C7AA LDY #&28 ;and line/column to restore old values C7AC JMP &CDDE ;exchange &300/1+X with &300/1+Y ************************************************************************* * * * VDU 13 - CARRIAGE RETURN * * * ************************************************************************* C7AF JSR &C588 ;A=0 if text cursor A=&20 if graphics cursor C7B2 BEQ &C7B7 ;if text C7B7 C7B4 JMP &CFAD ;else set graphics cursor to left hand columm C7B7 JSR &CE6E ;set text column to left hand column C7BA JMP &C6AF ;set up cursor and display address C7BD JSR &CFA6 ;home graphic cursor ************************************************************************* * * * VDU 16 - CLEAR GRAPHICS SCREEN * * CLG * * * ************************************************************************* C7C0 LDA &0361 ;pixels per byte C7C3 BEQ &C7F8 ;if 0 current mode has no graphics so exit C7C5 LDX &035A ;Background graphics colour C7C8 LDY &035C ;background graphics plot mode (GCOL n) C7CB JSR &D0B3 ;set graphics byte mask in &D4/5 C7CE LDX #&00 ;graphics window C7D0 LDY #&28 ;workspace C7D2 JSR &D47C ;set(300/7+Y) from (300/7+X) C7D5 SEC ;set carry C7D6 LDA &0306 ;graphics window top low C7D9 SBC &0302 ;graphics window bottom low C7DC TAY ;Y=difference C7DD INY ;increment C7DE STY &0330 ;and store in workspace (this is line count) C7E1 LDX #&2C ; C7E3 LDY #&28 ; C7E5 JSR &D6A6 ;clear line C7E8 LDA &032E ;decrement window height in pixels C7EB BNE &C7F0 ; C7ED DEC &032F ; C7F0 DEC &032E ; C7F3 DEC &0330 ;decrement line count C7F6 BNE &C7E1 ;if <>0 then do it again C7F8 RTS ;exit ************************************************************************* * * * VDU 17 - DEFINE TEXT COLOUR * * COLOUR n * * * * 1 parameter * * * ************************************************************************* ;parameter in &0323 C7F9 LDY #&00 ;Y=0 C7FB BEQ &C7FF ;jump to C7FF ************************************************************************* * * * VDU 18 - DEFINE GRAPHICS COLOUR * * GCOL k,c * * * * 2 parameters * * * ************************************************************************* ;parameters in 323,322 C7FD LDY #&02 ;Y=2 C7FF LDA &0323 ;get last parameter C802 BPL &C805 ;if +ve it's foreground colour so C805 C804 INY ;else Y=Y+1 C805 AND &0360 ;number of logical colours less 1 C808 STA &DA ;store it C80A LDA &0360 ;number of logical colours less 1 C80D BEQ &C82B ;if none exit C80F AND #&07 ;else limit to an available colour and clear M C811 CLC ;clear carry C812 ADC &DA ;Add last parameter to get pointer to table C814 TAX ;pointer into X C815 LDA &C423,X ;get colour bitmap from table C818 STA &0357,Y ; colour Y=0=text fgnd, 1=text bkgnd, 2=graphics fg, etc C81B CPY #&02 ;If Y>1 C81D BCS &C82C ;then its graphics so C82C else C81F LDA &0357 ;foreground text colour C822 EOR #&FF ;invert C824 STA &D3 ;text colour byte to be orred or EORed into memory C826 EOR &0358 ;background text colour C829 STA &D2 ;text colour byte to be orred or EORed into memory C82B RTS ;and exit ; C82C LDA &0322 ; Get GCOL action C82F STA &0359,Y ; Store at &35B foreground, &35C background C832 RTS ; exit ************************************************************************* * * * VDU 20 - RESTORE DEFAULT COLOURS * * * ************************************************************************* ; C833 LDA #&20 ; SPACE character for teletext background C835 STA &0358 ; Set as background "colour" C838 RTS ; ; C839 LDX #&05 ; X=5 C83B LDA #&00 ; A=0 C83D STA &0357,X ; Zero all colour settings C840 DEX ; txtfgd, txtbgd, gfxfdg, gfxbgd, gcolgfd, gcolbgd C841 BPL &C83D ; C843 LDX &0360 ; Number of logical colours less 1 C846 BEQ &C833 ; If zero, teletext so to C833 to set ttxt background C848 LDA #&FF ; A=&FF C84A CPX #&0F ; Is it a 16-colour MODE? C84C BNE &C850 ; Not 16 colours, skip past C84E LDA #&3F ; A=&3F for <16 colours, A=&FF for 16 colours C850 STA &0357 ;foreground text colour C853 STA &0359 ;foreground graphics colour C856 EOR #&FF ;invert A C858 STA &D2 ;text colour byte to be ORed or EORed into memory C85A STA &D3 ;text colour byte to be ORed or EORed into memory C85C STX &031F ;set first parameter of 5 C85F CPX #&03 ;if there are 4 colours C861 BEQ &C874 ;goto C874 C863 BCC &C885 ;if less there are 2 colours goto C885 ;else there are 16 colours C865 STX &0320 ;set second parameter C868 JSR &C892 ;do VDU 19 etc C86B DEC &0320 ;decrement first parameter C86E DEC &031F ;and last parameter C871 BPL &C868 ; C873 RTS ; ; ********* 4 colour mode ************************************************* C874 LDX #&07 ;X=7 C876 STX &0320 ;set first parameter C879 JSR &C892 ;and do VDU 19 C87C LSR &0320 ; C87F DEC &031F ; C882 BPL &C879 ; C884 RTS ;exit ;********* 2 colour mode ************************************************ C885 LDX #&07 ;X=7 C887 JSR &C88F ;execute VDU 19 C88A LDX #&00 ;X=0 C88C STX &031F ;store it as C88F STX &0320 ;both parameters ************************************************************************* * * * VDU 19 - DEFINE COLOURS * * [COLOUR l,p] * * [COLOUR l,r,g,b] * * * * 5 parameters * * * ************************************************************************* ;&31F=first parameter logical colour ;&320=second physical colour C892 PHP ;push processor flags C893 SEI ;disable interrupts C894 LDA &031F ;get first parameter and C897 AND &0360 ;number of logical colours less 1 C89A TAX ;to make legal, then X=A C89B LDA &0320 ;A=second parameter C89E AND #&0F ;make legal C8A0 STA &036F,X ;colour pallette C8A3 TAY ;Y=A C8A4 LDA &0360 ;number of logical colours less 1 C8A7 STA &FA ;store it C8A9 CMP #&03 ;is it 4 colour mode?? C8AB PHP ;save flags C8AC TXA ;A=X C8AD ROR ;rotate A into &FA C8AE ROR &FA ; C8B0 BCS &C8AD ; C8B2 ASL &FA ; C8B4 TYA ;A=Y C8B5 ORA &FA ; C8B7 TAX ; C8B8 LDY #&00 ;Y=0 C8BA PLP ;check flags C8BB PHP ; C8BC BNE &C8CC ;if A<>3 earlier C8CC C8BE AND #&60 ;else A=&60 to test bits 5 and 6 C8C0 BEQ &C8CB ;if not set C8CB C8C2 CMP #&60 ;else if both set C8C4 BEQ &C8CB ;C8CB C8C6 TXA ;A=X C8C7 EOR #&60 ;invert C8C9 BNE &C8CC ;and if not 0 C8CC C8CB TXA ;X=A C8CC JSR &EA11 ;call Osbyte 155 pass data to pallette register C8CF TYA ; C8D0 SEC ; C8D1 ADC &0360 ;number of logical colours less 1 C8D4 TAY ; C8D5 TXA ; C8D6 ADC #&10 ; C8D8 TAX ; C8D9 CPY #&10 ;if Y<16 do it again C8DB BCC &C8BA ; C8DD PLP ;pull flags twice C8DE PLP ; C8DF RTS ;and exit ************************************************************************* * * * OSWORD 12 - WRITE PALLETTE * * * ************************************************************************* ;on entry X=&F0:Y=&F1:YX points to parameter block ;byte 0 = logical colour; byte 1 physical colour; bytes 2-4=0 C8E0 PHP ;push flags C8E1 AND &0360 ;and with number of logical colours less 1 C8E4 TAX ;X=A C8E5 INY ;Y=Y+1 C8E6 LDA (&F0),Y ;get physical colour C8E8 JMP &C89E ;do VDU19 with parameters in X and A ************************************************************************* * * * VDU 22 - SELECT MODE * * MODE n * * * * 1 parameter * * * ************************************************************************* ;parameter in &323 C8EB LDA &0323 ;get parameter C8EE JMP &CB33 ;goto CB33 ************************************************************************* * * * VDU 23 - DEFINE CHARACTERS * * * * 9 parameters * * * ************************************************************************* ;parameters are:- ;31B character to define ;31C to 323 definition C8F1 LDA &031B ;get character to define C8F4 CMP #&20 ;is it ' ' C8F6 BCC &C93F ;if less then it is a control instruction, go to C93F C8F8 PHA ;else save parameter C8F9 LSR ;A=A/32 C8FA LSR ; C8FB LSR ; C8FC LSR ; C8FD LSR ; C8FE TAX ;X=A C8FF LDA &C40D,X ;get font flag mask from table (A=&80/2^X) C902 BIT &0367 ;font flag C905 BNE &C927 ;and if A<>0 C927 storage area is established already C907 ORA &0367 ;or with font flag to set bit found to be 0 C90A STA &0367 ;font flag C90D TXA ;get A back C90E AND #&03 ;And 3 to clear all but bits 0 and 1 C910 CLC ;clear carry C911 ADC #&BF ;add &BF (A=&C0,&C1,&C2) to select a character page C913 STA &DF ;store it C915 LDA &0367,X ;get font location byte (normally &0C) C918 STA &DD ;store it C91A LDY #&00 ;Y=0 so (&DE) holds (&C000 -&C2FF) C91C STY &DC ; C91E STY &DE ; C920 LDA (&DE),Y ;transfer page to storage area C922 STA (&DC),Y ; C924 DEY ; C925 BNE &C920 ; C927 PLA ;get A back C928 JSR &D03E ;set up character definition pointers C92B LDY #&07 ;Y=7 C92D LDA &031C,Y ;transfer definition parameters C930 STA (&DE),Y ;to RAM definition C932 DEY ; C933 BPL &C92D ; C935 RTS ;and exit ; C936 PLA ;Pull A C937 RTS ;and exit ************ VDU EXTENSION ********************************************** C938 LDA &031F ;A=PLOT action number from VDU 25 C93B CLC ;clear carry=PLOT C93C JMP (&0226) ;jump via VDUV vector, A=PLOT number or VDU 23 number ********** VDU control commands ***************************************** C93F CMP #&01 ;is A=1 C941 BCC &C958 ;if less (0) then set CRT register directly C943 BNE &C93C ;if not 1 jump to VDUV with CS for VDU extension ********** turn cursor on/off ******************************************* C945 JSR &C588 ;A=0 if text cursor, A=&20 if graphics cursor C948 BNE &C937 ;if graphics exit C94A LDA #&20 ;A=&20 - preload to turn cursor off C94C LDY &031C ;Y=second VDU parameter C94F BEQ &C954 ;if 0, jump to C954 to turn cursor off C951 LDA &035F ;get last setting of CRT controller register ;for cursor on C954 LDY #&0A ;Y=10 - cursor control register number C956 BNE &C985 ;jump to C985, Y=register, Y=value ********** set CRT controller ******************************************* C958 LDA &031D ;get third parameter - value C95B LDY &031C ;and second parameter - register C95E CPY #&07 ;is Y=7 C960 BCC &C985 ;if less C985 C962 BNE &C967 ;else if >7 C967 C964 ADC &0290 ;else ADD screen vertical display adjustment C967 CPY #&08 ;If Y<>8 C969 BNE &C972 ;C972 C96B ORA #&00 ;if bit 7 set C96D BMI &C972 ;C972 C96F EOR &0291 ;else EOR with interlace toggle C972 CPY #&0A ;Y=10?? C974 BNE &C985 ;if not C985 C976 STA &035F ;last setting of CRT controller register C979 TAY ;Y=A C97A LDA &D0 ;VDU status byte C97C AND #&20 ;check bit 5 printing at graphics cursor? C97E PHP ;push flags C97F TYA ;Y=A C980 LDY #&0A ;Y=10 C982 PLP ;pull flags C983 BNE &C98B ;if graphics in use then C98B C985 STY &FE00 ;else set CRTC address register C988 STA &FE01 ;and poke new value to register Y C98B RTS ;exit ************************************************************************* * * * VDU 25 - PLOT * * PLOT k,x,y * * DRAW x,y * * MOVE x,y * * PLOT x,y * * 5 parameters * * * ************************************************************************* ; C98C LDX &0361 ;pixels per byte C98F BEQ &C938 ;if no graphics available go to VDU Extension C991 JMP &D060 ;else enter Plot routine at D060 ********** adjust screen RAM addresses ********************************** C994 LDX &0350 ;window area start address lo C997 LDA &0351 ;window area start address hi C99A JSR &CCF8 ;subtract bytes per character row from this C99D BCS &C9B3 ;if no wraparound needed C9B3 C99F ADC &0354 ;screen RAM size hi byte to wrap around C9A2 BCC &C9B3 ; C9A4 LDX &0350 ;window area start address lo C9A7 LDA &0351 ;window area start address hi C9AA JSR &CAD4 ;add bytes per char. row C9AD BPL &C9B3 ; C9AF SEC ;wrap around in other direction C9B0 SBC &0354 ;screen RAM size hi byte C9B3 STA &0351 ;window area start address hi C9B6 STX &0350 ;window area start address lo C9B9 LDY #&0C ;Y=12 C9BB BNE &CA0E ;jump to CA0E ************************************************************************* * * * VDU 26 - SET DEFAULT WINDOWS * * * ************************************************************************* C9BD LDA #&00 ;A=0 C9BF LDX #&2C ;X=&2C C9C1 STA &0300,X ;clear all windows C9C4 DEX ; C9C5 BPL &C9C1 ;until X=&FF C9C7 LDX &0355 ;screen mode C9CA LDY C3EF,X ;text window right hand margin maximum C9CD STY &030A ;text window right C9D0 JSR &CA88 ;calculate number of bytes in a line C9D3 LDY &C3E7,X ;text window bottom margin maximum C9D6 STY &0309 ;bottom margin C9D9 LDY #&03 ;Y=3 C9DB STY &0323 ;set as last parameter C9DE INY ;increment Y C9DF STY &0321 ;set parameters C9E2 DEC &0322 ; C9E5 DEC &0320 ; C9E8 JSR &CA39 ;and do VDU 24 C9EB LDA #&F7 ; C9ED JSR &C5A8 ;clear bit 3 of &D0 C9F0 LDX &0350 ;window area start address lo C9F3 LDA &0351 ;window area start address hi C9F6 STX &034A ;text cursor 6845 address C9F9 STA &034B ;text cursor 6845 address C9FC BPL &CA02 ;set cursor position C9FE SEC ; C9FF SBC &0354 ;screen RAM size hi byte **************** set cursor position ************************************ CA02 STX &D8 ;set &D8/9 from X/A CA04 STA &D9 ; CA06 LDX &034A ;text cursor 6845 address CA09 LDA &034B ;text cursor 6845 address CA0C LDY #&0E ;Y=15 CA0E PHA ;Push A CA0F LDA &0355 ;screen mode CA12 CMP #&07 ;is it mode 7? - should check map type or colours=0 CA14 PLA ;get back A CA15 BCS &CA27 ;if mode 7 selected CA27 CA17 STX &DA ;else store X CA19 LSR ;divide X/A by 8 CA1A ROR &DA ; CA1C LSR ; CA1D ROR &DA ; CA1F LSR ; CA20 ROR &DA ; CA22 LDX &DA ; CA24 JMP &CA2B ;goto CA2B CA27 SBC #&74 ;mode 7 subtract &74 CA29 EOR #&20 ;EOR with &20 CA2B STY &FE00 ;write to CRTC address file register CA2E STA &FE01 ;and to relevant address (register 14) CA31 INY ;Increment Y CA32 STY &FE00 ;write to CRTC address file register CA35 STX &FE01 ;and to relevant address (register 15) CA38 RTS ;and RETURN