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Diffstat (limited to 'docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/CDED')
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diff --git a/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/CDED b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/CDED new file mode 100644 index 0000000..ef1ac9b --- /dev/null +++ b/docs/os12/mdfs.net/Docs/Comp/BBC/OS1-20/CDED @@ -0,0 +1 @@ +CDED PHA ;store it
CDEE LDA &0300,Y ;get byte pointed to by Y
CDF1 STA &0300,X ;put it in 300+X
CDF4 PLA ;get back A
CDF5 STA &0300,Y ;put it in 300+Y
CDF8 INX ;increment pointers
CDF9 INY ;
CDFA DEC &DA ;decrement loop counter
CDFC BNE &CDEA ;and if not 0 do it again
CDFE RTS ;and exit
******** execute upward scroll ******************************************
;
CDFF JSR &CE5B ;exchange line and column cursors with workspace copies
CE02 LDY &030B ;top of text window
CE05 STY &0319 ;current text line
CE08 JSR &CF06 ;set up display address
CE0B JSR &CAD4 ;add bytes per char. row
CE0E BPL &CE14 ;
CE10 SEC ;
CE11 SBC &0354 ;screen RAM size hi byte
CE14 STA &DB ;(&DA)=X/A
CE16 STX &DA ;
CE18 STA &DC ;&DC=A
CE1A BCC &CE22 ;
CE1C JSR &CE73 ;copy line to new position
;using (&DA) for read
;and (&D8) for write
CE1F JMP &CE2A ;exit
CE22 JSR &CAD4 ;add bytes per char. row
CE25 BMI &CE1C ;if outside screen RAM CE1C
CE27 JSR &CE38 ;perform a copy
CE2A LDA &DC ;
CE2C LDX &DA ;
CE2E STA &D9 ;
CE30 STX &D8 ;
CE32 DEC &DE ;decrement window height
CE34 BNE &CE0B ;CE0B if not 0
CE36 BEQ &CDDA ;exchange text column/linelse CDDA
*********** copy routines ***********************************************
CE38 LDX &034D ;text window width hi (bytes)
CE3B BEQ &CE4D ;if no more than 256 bytes to copy X=0 so CE4D
CE3D LDY #&00 ;Y=0 to set loop counter
CE3F LDA (&DA),Y ;copy 256 bytes
CE41 STA (&D8),Y ;
CE43 INY ;
CE44 BNE &CE3F ;Till Y=0 again
CE46 INC &D9 ;increment hi bytes
CE48 INC &DB ;
CE4A DEX ;decrement window width
CE4B BNE &CE3F ;if not 0 go back and do loop again
CE4D LDY &034C ;text window width lo (bytes)
CE50 BEQ &CE5A ;if Y=0 CE5A
CE52 DEY ;else Y=Y-1
CE53 LDA (&DA),Y ;copy Y bytes
CE55 STA (&D8),Y ;
CE57 TYA ;A=Y
CE58 BNE &CE52 ;if not 0 CE52
CE5A RTS ;and exit
;
CE5B JSR &CDDA ;exchange text column/line with workspace
CE5E SEC ;set carry
CE5F LDA &0309 ;bottom margin
CE62 SBC &030B ;top of text window
CE65 STA &DE ;store it
CE67 BNE &CE6E ;set text column to left hand column
CE69 PLA ;get back return address
CE6A PLA ;
CE6B JMP &CDDA ;exchange text column/line with workspace
CE6E LDA &0308 ;text window left
CE71 BPL &CEE3 ;Jump CEE3 always!
CE73 LDA &DA ;get back A
CE75 PHA ;push A
CE76 SEC ;set carry
CE77 LDA &030A ;text window right
CE7A SBC &0308 ;text window left
CE7D STA &DF ;
CE7F LDY &034F ;bytes per character to set loop counter
CE82 DEY ;copy loop
CE83 LDA (&DA),Y ;
CE85 STA (&D8),Y ;
CE87 DEY ;
CE88 BPL &CE83 ;
CE8A LDX #&02 ;X=2
CE8C CLC ;clear carry
CE8D LDA &D8,X ;
CE8F ADC &034F ;bytes per character
CE92 STA &D8,X ;
CE94 LDA &D9,X ;
CE96 ADC #&00 ;
CE98 BPL &CE9E ;if this remains in screen RAM OK
CE9A SEC ;else wrap around screen
CE9B SBC &0354 ;screen RAM size hi byte
CE9E STA &D9,X ;
CEA0 DEX ;X=X-2
CEA1 DEX ;
CEA2 BEQ &CE8C ;if X=0 adjust second set of pointers
CEA4 DEC &DF ;decrement window width
CEA6 BPL &CE7F ;and if still +ve do it all again
CEA8 PLA ;get back A
CEA9 STA &DA ;and store it
CEAB RTS ;then exit
;
*********** clear a line ************************************************
CEAC LDA &0318 ;text column
CEAF PHA ;save it
CEB0 JSR &CE6E ;set text column to left hand column
CEB3 JSR &CF06 ;set up display address
CEB6 SEC ;set carry
CEB7 LDA &030A ;text window right
CEBA SBC &0308 ;text window left
CEBD STA &DC ;as window width
CEBF LDA &0358 ;background text colour
CEC2 LDY &034F ;bytes per character
CEC5 DEY ;Y=Y-1 decrementing loop counter
CEC6 STA (&D8),Y ;store background colour at this point on screen
CEC8 BNE &CEC5 ;if Y<>0 do it again
CECA TXA ;else A=X
CECB CLC ;clear carry to add
CECC ADC &034F ;bytes per character
CECF TAX ;X=A restoring it
CED0 LDA &D9 ;get hi byte
CED2 ADC #&00 ;Add carry if any
CED4 BPL &CEDA ;if +ve CeDA
CED6 SEC ;else wrap around
CED7 SBC &0354 ;screen RAM size hi byte
CEDA STX &D8 ;restore D8/9
CEDC STA &D9 ;
CEDE DEC &DC ;decrement window width
CEE0 BPL &CEBF ;ind if not 0 do it all again
CEE2 PLA ;get back A
CEE3 STA &0318 ;restore text column
CEE6 SEC ;set carry
CEE7 RTS ;and exit
;
CEE8 LDX &0318 ;text column
CEEB CPX &0308 ;text window left
CEEE BMI &CEE6 ;if less than left margin return with carry set
CEF0 CPX &030A ;text window right
CEF3 BEQ &CEF7 ;if equal to right margin thats OK
CEF5 BPL &CEE6 ;if greater than right margin return with carry set
CEF7 LDX &0319 ;current text line
CEFA CPX &030B ;top of text window
CEFD BMI &CEE6 ;if less than top margin
CEFF CPX &0309 ;bottom margin
CF02 BEQ &CF06 ;set up display address
CF04 BPL &CEE6 ;or greater than bottom margin return with carry set
************:set up display address *************************************
;Mode 0: (0319)*640+(0318)* 8
;Mode 1: (0319)*640+(0318)*16
;Mode 2: (0319)*640+(0318)*32
;Mode 3: (0319)*640+(0318)* 8
;Mode 4: (0319)*320+(0318)* 8
;Mode 5: (0319)*320+(0318)*16
;Mode 6: (0319)*320+(0318)* 8
;Mode 7: (0319)* 40+(0318)
;this gives a displacement relative to the screen RAM start address
;which is added to the calculated number and stored in in 34A/B
;if the result is less than &8000, the top of screen RAM it is copied into X/A
;and D8/9.
;if the result is greater than &7FFF the hi byte of screen RAM size is
;subtracted to wraparound the screen. X/A, D8/9 are then set from this
CF06 LDA &0319 ;current text line
CF09 ASL ;A=A*2
CF0A TAY ;Y=A
CF0B LDA (&E0),Y ;get CRTC multiplication table pointer
CF0D STA &D9 ;&D9=A
CF0F INY ;Y=Y+1
CF10 LDA #&02 ;A=2
CF12 AND &0356 ;memory map type
CF15 PHP ;save flags
CF16 LDA (&E0),Y ;get CRTC multiplication table pointer
CF18 PLP ;pull flags
CF19 BEQ &CF1E ;
CF1B LSR &D9 ;&D9=&D9/2
CF1D ROR ;A=A/2 +(128*carry)
CF1E ADC &0350 ;window area start address lo
CF21 STA &D8 ;store it
CF23 LDA &D9 ;
CF25 ADC &0351 ;window area start address hi
CF28 TAY ;
CF29 LDA &0318 ;text column
CF2C LDX &034F ;bytes per character
CF2F DEX ;X=X-1
CF30 BEQ &CF44 ;if X=0 mode 7 CF44
CF32 CPX #&0F ;is it mode 1 or mode 5?
CF34 BEQ &CF39 ;yes CF39 with carry set
CF36 BCC &CF3A ;if its less (mode 0,3,4,6) CF3A
CF38 ASL ;A=A*16 if entered here (mode 2)
CF39 ASL ;A=A*8 if entered here
CF3A ASL ;A=A*4 if entered here
CF3B ASL ;
CF3C BCC &CF40 ;if carry clear
CF3E INY ;Y=Y+2
CF3F INY ;
CF40 ASL ;A=A*2
CF41 BCC &CF45 ;if carry clear add to &D8
CF43 INY ;if not Y=Y+1
CF44 CLC ;clear carry
CF45 ADC &D8 ;add to &D8
CF47 STA &D8 ;and store it
CF49 STA &034A ;text cursor 6845 address
CF4C TAX ;X=A
CF4D TYA ;A=Y
CF4E ADC #&00 ;Add carry if set
CF50 STA &034B ;text cursor 6845 address
CF53 BPL &CF59 ;if less than &800 goto &CF59
CF55 SEC ;else wrap around
CF56 SBC &0354 ;screen RAM size hi byte
CF59 STA &D9 ;store in high byte
CF5B CLC ;clear carry
CF5C RTS ;and exit
******** Graphics cursor display routine ********************************
CF5D LDX &0359 ;foreground graphics colour
CF60 LDY &035B ;foreground graphics plot mode (GCOL n)
CF63 JSR &D0B3 ;set graphics byte mask in &D4/5
CF66 JSR &D486 ;copy (324/7) graphics cursor to workspace (328/B)
CF69 LDY #&00 ;Y=0
CF6B STY &DC ;&DC=Y
CF6D LDY &DC ;Y=&DC
CF6F LDA (&DE),Y ;get pattern byte
CF71 BEQ &CF86 ;if A=0 CF86
CF73 STA &DD ;else &DD=A
CF75 BPL &CF7A ;and if >0 CF7A
CF77 JSR &D0E3 ;else display a pixel
CF7A INC &0324 ;current horizontal graphics cursor
CF7D BNE &CF82 ;
CF7F INC &0325 ;current horizontal graphics cursor
CF82 ASL &DD ;&DD=&DD*2
CF84 BNE &CF75 ;and if<>0 CF75
CF86 LDX #&28 ;point to workspace
CF88 LDY #&24 ;point to horizontal graphics cursor
CF8A JSR &D482 ;0300/1+Y=0300/1+X
CF8D LDY &0326 ;current vertical graphics cursor
CF90 BNE &CF95 ;
CF92 DEC &0327 ;current vertical graphics cursor
CF95 DEC &0326 ;current vertical graphics cursor
CF98 LDY &DC ;
CF9A INY ;
CF9B CPY #&08 ;if Y<8 then do loop again
CF9D BNE &CF6B ;else
CF9F LDX #&28 ;point to workspace
CFA1 LDY #&24 ;point to graphics cursor
CFA3 JMP &D48A ;(&300/3+Y)=(&300/3+X)
*********** home graphics cursor ***************************************
CFA6 LDX #&06 ;point to graphics window TOP
CFA8 LDY #&26 ;point to workspace
CFAA JSR &D482 ;0300/1+Y=0300/1+X
************* set graphics cursor to left hand column *******************
CFAD LDX #&00 ;X=0 point to graphics window left
CFAF LDY #&24 ;Y=&24
CFB1 JSR &D482 ;0300/1+Y=0300/1+X
CFB4 JMP &D1B8 ;set up external coordinates for graphics
CFB7 LDX &0360 ;number of logical colours less 1
CFBA BEQ &CFDC ;if MODE 7 CFDC
CFBC JSR &D03E ;set up character definition pointers
CFBF LDX &0360 ;number of logical colours less 1
CFC2 LDA &D0 ;VDU status byte
CFC4 AND #&20 ;and out bit 5 printing at graphics cursor
CFC6 BNE &CF5D ;if set CF5D
CFC8 LDY #&07 ;else Y=7
CFCA CPX #&03 ;if X=3
CFCC BEQ &CFEE ;goto CFEE to handle 4 colour modes
CFCE BCS &D01E ;else if X>3 D01E to deal with 16 colours
CFD0 LDA (&DE),Y ;get pattern byte
CFD2 ORA &D2 ;text colour byte to be orred or EORed into memory
CFD4 EOR &D3 ;text colour byte to be orred or EORed into memory
CFD6 STA (&D8),Y ; write to screen
CFD8 DEY ;Y=Y-1
CFD9 BPL &CFD0 ;if still +ve do loop again
CFDB RTS ;and exit
******* convert teletext characters *************************************
;mode 7
CFDC LDY #&02 ;Y=2
CFDE CMP &C4B6,Y ;compare with teletext conversion table
CFE1 BEQ &CFE9 ;if equal then CFE9
CFE3 DEY ;else Y=Y-1
CFE4 BPL &CFDE ;and if +ve CFDE
CFE6 STA (&D8,X) ;if not write byte to screen
CFE8 RTS ;and exit
CFE9 LDA &C4B7,Y ;convert with teletext conversion table
CFEC BNE &CFE6 ;and write it
***********four colour modes ********************************************
CFEE LDA (&DE),Y ;get pattern byte
CFF0 PHA ;save it
CFF1 LSR ;move hi nybble to lo
CFF2 LSR ;
CFF3 LSR ;
CFF4 LSR ;
CFF5 TAX ;X=A
CFF6 LDA &C31F,X ;4 colour mode byte mask look up table
CFF9 ORA &D2 ;text colour byte to be orred or EORed into memory
CFFB EOR &D3 ;text colour byte to be orred or EORed into memory
CFFD STA (&D8),Y ; write to screen
CFFF TYA ;A=Y
D000 CLC ;clear carry
D001 ADC #&08 ;add 8 to move screen RAM pointer 8 bytes
D003 TAY ;Y=A
D004 PLA ;get back A
D005 AND #&0F ;clear high nybble
D007 TAX ;X=A
D008 LDA &C31F,X ;4 colour mode byte mask look up table
D00B ORA &D2 ;text colour byte to be orred or EORed into memory
D00D EOR &D3 ;text colour byte to be orred or EORed into memory
D00F STA (&D8),Y ; write to screen
D011 TYA ;A=Y
D012 SBC #&08 ;A=A-9
D014 TAY ;Y=A
D015 BPL &CFEE ;if +ve do loop again
D017 RTS ;exit
D018 TYA ;Y=Y-&21
D019 SBC #&21 ;
D01B BMI &D017 ;IF Y IS negative then RETURN
D01D TAY ;else A=Y
******* 16 COLOUR MODES *************************************************
D01E LDA (&DE),Y ;get pattern byte
D020 STA &DC ;store it
D022 SEC ;set carry
D023 LDA #&00 ;A=0
D025 ROL &DC ;carry now occupies bit 0 of DC
D027 BEQ &D018 ;when DC=0 again D018 to deal with next pattern byte
D029 ROL ;get bit 7 from &DC into A bit 0
D02A ASL &DC ;rotate again to get second
D02C ROL ;bit into A
D02D TAX ;and store result in X
D02E LDA &C32F,X ;multiply by &55 using look up table
D031 ORA &D2 ;and set colour factors
D033 EOR &D3 ;
D035 STA (&D8),Y ;and store result
D037 CLC ;clear carry
D038 TYA ;Y=Y+8 moving screen RAM pointer on 8 bytes
D039 ADC #&08 ;
D03B TAY ;
D03C BCC &D023 ;iloop to D023 to deal with next bit pair
************* calculate pattern address for given code ******************
;A contains code on entry = 12345678
D03E ASL ;23456780 C holds 1
D03F ROL ;34567801 C holds 2
D040 ROL ;45678012 C holds 3
D041 STA &DE ;save this pattern
D043 AND #&03 ;00000012
D045 ROL ;00000123 C=0
D046 TAX ;X=A=0 - 7
D047 AND #&03 ;A=00000023
D049 ADC #&BF ;A=&BF,C0 or C1
D04B TAY ;this is used as a pointer
D04C LDA &C40D,X ;A=&80/2^X i.e.1,2,4,8,&10,&20,&40, or &80
D04F BIT &0367 ;with font flag
D052 BEQ &D057 ;if 0 D057
D054 LDY &0367,X ;else get hi byte from table
D057 STY &DF ;store Y
D059 LDA &DE ;get back pattern
D05B AND #&F8 ;convert to 45678000
D05D STA &DE ;and re store it
D05F RTS ;exit
;
*************************************************************************
*************************************************************************
** **
** **
** PLOT ROUTINES ENTER HERE **
** **
** **
*************************************************************************
*************************************************************************
;on entry ADDRESS PARAMETER DESCRIPTION
; 031F 1 plot type
; 0320/1 2,3 X coordinate
; 0322/3 4,5 Y coordinate
D060 LDX #&20 ;X=&20
D062 JSR &D14D ;translate coordinates
D065 LDA &031F ;get plot type
D068 CMP #&04 ;if its 4
D06A BEQ &D0D9 ;D0D9 move absolute
D06C LDY #&05 ;Y=5
D06E AND #&03 ;mask only bits 0 and 1
D070 BEQ &D080 ;if result is 0 then its a move (multiple of 8)
D072 LSR ;else move bit 0 int C
D073 BCS &D078 ;if set then D078 graphics colour required
D075 DEY ;Y=4
D076 BNE &D080 ;logic inverse colour must be wanted
******** graphics colour wanted *****************************************
D078 TAX ;X=A if A=0 its a foreground colour 1 its background
D079 LDY &035B,X ;get fore or background graphics PLOT mode
D07C LDA &0359,X ;get fore or background graphics colour
D07F TAX ;X=A
D080 JSR &D0B3 ;set up colour masks in D4/5
D083 LDA &031F ;get plot type
D086 BMI &D0AB ;if &80-&FF then D0AB type not implemented
D088 ASL ;bit 7=bit 6
D089 BPL &D0C6 ;if bit 6 is 0 then plot type is 0-63 so D0C6
D08B AND #&F0 ;else mask out lower nybble
D08D ASL ;shift old bit 6 into C bit old 5 into bit 7
D08E BEQ &D0D6 ;if 0 then type 64-71 was called single point plot
;goto D0D6
D090 EOR #&40 ;if bit 6 NOT set type &80-&87 fill triangle
D092 BEQ &D0A8 ;so D0A8
D094 PHA ;else push A
D095 JSR &D0DC ;copy 0320/3 to 0324/7 setting XY in current graphics
;coordinates
D098 PLA ;get back A
D099 EOR #&60 ;if BITS 6 and 5 NOT SET type 72-79 lateral fill
D09B BEQ &D0AE ;so D0AE
D09D CMP #&40 ;if type 88-95 horizontal line blanking
D09F BNE &D0AB ;so D0AB
D0A1 LDA #&02 ;else A=2
D0A3 STA &DC ;store it
D0A5 JMP &D506 ;and jump to D506 type not implemented
D0A8 JMP &D5EA ;to fill triangle routine
D0AB JMP &C938 ;VDU extension access entry
D0AE STA &DC ;store A
D0B0 JMP &D4BF ;
*********:set colour masks **********************************************
;graphics mode in Y
;colour in X
D0B3 TXA ;A=X
D0B4 ORA &C41C,Y ;or with GCOL plot options table byte
D0B7 EOR &C41D,Y ;EOR with following byte
D0BA STA &D4 ;and store it
D0BC TXA ;A=X
D0BD ORA &C41B,Y ;
D0C0 EOR &C420,Y ;
D0C3 STA &D5 ;
D0C5 RTS ;exit with masks in &D4/5
************** analyse first parameter in 0-63 range ********************
;
D0C6 ASL ;shift left again
D0C7 BMI &D0AB ;if -ve options are in range 32-63 not implemented
D0C9 ASL ;shift left twice more
D0CA ASL ;
D0CB BPL &D0D0 ;if still +ve type is 0-7 or 16-23 so D0D0
D0CD JSR &D0EB ;else display a point
D0D0 JSR &D1ED ;perform calculations
D0D3 JMP &D0D9 ;
*************************************************************************
* *
* PLOT A SINGLE POINT *
* *
*************************************************************************
D0D6 JSR &D0EB ;display a point
D0D9 JSR &CDE2 ;swap current and last graphics position
D0DC LDY #&24 ;Y=&24
D0DE LDX #&20 ;X=&20
D0E0 JMP &D48A ;copy parameters to 324/7 (300/3 +Y)
D0E3 LDX #&24 ;
D0E5 JSR &D85F ;calculate position
D0E8 BEQ &D0F0 ;if result =0 then D0F0
D0EA RTS ;else exit
;
D0EB JSR &D85D ;calculate position
D0EE BNE &D103 ;if A<>0 D103 and return
D0F0 LDY &031A ;else get current graphics scan line
D0F3 LDA &D1 ;pick up and modify screen byte
D0F5 AND &D4 ;
D0F7 ORA (&D6),Y ;
D0F9 STA &DA ;
D0FB LDA &D5 ;
D0FD AND &D1 ;
D0FF EOR &DA ;
D101 STA (&D6),Y ;put it back again
D103 RTS ;and exit
;
D104 LDA (&D6),Y ;this is a more simplistic version of the above
D106 ORA &D4 ;
D108 EOR &D5 ;
D10A STA (&D6),Y ;
D10C RTS ;and exit
\ No newline at end of file |