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Additional cleanup of CVDU driver

import/raw
wayne 13 years ago
parent
7d133e3790
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d5d20d9f98
1 changed files with 178 additions and 197 deletions
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  1. 375
      branches/wbw/Source/cvdu.asm

375
branches/wbw/Source/cvdu.asm
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@ -1,78 +1,78 @@
;__CVDUDRIVER_______________________________________________________________________________________
;
;======================================================================
; COLOR VDU DRIVER FOR N8VEM PROJECT
;
; WRITTEN BY: DAN WERNER -- 11/4/2011
; REMAINDER WRITTEN BY: DAN WERNER -- 11/7/2009
; ROMWBW ADAPTATION BY: WAYNE WARTHEN -- 11/9/2012
;__________________________________________________________________________________________________
;======================================================================
;
; TODO:
; - IMPLEMENT CONSTANTS FOR SCREEN DIMENSIONS
; - IMPLEMENT SET CURSOR STYLE (VDASCS) FUNCTION
; - IMPLEMENT ALTERNATE DISPLAY MODES?
; - IMPLEMENT DYNAMIC READ/WRITE OF CHARACTER BITMAP DATA?
;
;__________________________________________________________________________________________________
; DATA CONSTANTS
;__________________________________________________________________________________________________
;======================================================================
; CVDU DRIVER - CONSTANTS
;======================================================================
;
CVDU_STAT .EQU $E4 ; READ M8563 STATUS
CVDU_REG .EQU $E4 ; SELECT M8563 REGISTER
CVDU_DATA .EQU $EC ; READ/WRITE M8563 DATA
;
;__________________________________________________________________________________________________
; BOARD INITIALIZATION
;__________________________________________________________________________________________________
;======================================================================
; CVDU DRIVER - INITIALIZATION
;======================================================================
;
CVDU_INIT:
CALL CVDU_CRTINIT
CALL CVDU_LOADFONT
CALL CVDU_CRTINIT ; SETUP THE CVDU CHIP REGISTERS
CALL CVDU_LOADFONT ; LOAD FONT DATA FROM ROM TO CVDU STRORAGE
CVDU_RESET:
LD A,14
LD (CVDU_ATTR),A
XOR A
LD (CVDU_X),A
LD (CVDU_Y),A
LD DE,0
LD (CVDU_DISPLAYPOS),DE
LD A,$0E ; ATTRIBUTE IS STANDARD WHITE ON BLACK
LD (CVDU_ATTR),A ; SAVE IT
LD A,'#'
LD DE,$800
CALL CVDU_FILL
CALL CVDU_XY
LD A,'#' ; BLANK THE SCREEN
LD DE,$800 ; FILL ENTIRE BUFFER
CALL CVDU_FILL ; DO IT
LD DE,0 ; ROW = 0, COL = 0
CALL CVDU_XY ; SEND CURSOR TO TOP LEFT
XOR A
XOR A ; SIGNAL SUCCESS
RET
;
;__________________________________________________________________________________________________
; CHARACTER I/O (CIO) FUNCTION JUMP TABLE
;__________________________________________________________________________________________________
;======================================================================
; CVDU DRIVER - CHARACTER I/O (CIO) DISPATCHER AND FUNCTIONS
;======================================================================
;
CVDU_DISPCIO:
LD A,B ; GET REQUESTED FUNCTION
AND $0F ; ISOLATE SUB-FUNCTION
JR Z,CVDU_CIOIN
LD A,B ; GET REQUESTED FUNCTION
AND $0F ; ISOLATE SUB-FUNCTION
JR Z,CVDU_CIOIN ; $00
DEC A
JR Z,CVDU_CIOOUT
JR Z,CVDU_CIOOUT ; $01
DEC A
JR Z,CVDU_CIOIST
JR Z,CVDU_CIOIST ; $02
DEC A
JR Z,CVDU_CIOOST
JR Z,CVDU_CIOOST ; $03
CALL PANIC
;
CVDU_CIOIN:
JP KBD_READ
JP KBD_READ ; CHAIN TO KEYBOARD DRIVER
;
CVDU_CIOIST:
JP KBD_STAT
JP KBD_STAT ; CHAIN TO KEYBOARD DRIVER
;
CVDU_CIOOUT:
JP CVDU_VDAWRC
JP CVDU_VDAWRC ; WRITE CHARACTER
;
CVDU_CIOOST:
XOR A
INC A
XOR A ; A = 0
INC A ; A = 1, SIGNAL OUTPUT BUFFER READY
RET
;
;__________________________________________________________________________________________________
; VIDEO DISPLAY ADAPTER (VDA) FUNCTION JUMP TABLE
;__________________________________________________________________________________________________
;======================================================================
; CVDU DRIVER - VIDEO DISPLAY ADAPTER (VDA) DISPATCHER AND FUNCTIONS
;======================================================================
;
CVDU_DISPVDA:
LD A,B ; GET REQUESTED FUNCTION
@ -118,17 +118,13 @@ CVDU_VDAQRY:
RET
CVDU_VDARES:
JP CVDU_RESET
JP CVDU_RESET ; DO THE RESET
CVDU_VDASCS:
CALL PANIC ; NOT IMPLEMENTED (YET)
CVDU_VDASCP:
LD A,E ; GET E
LD (CVDU_X),A ; SAVE AS COLUMN (X)
LD A,D ; GET D
LD (CVDU_Y),A ; SAVE AS ROW (Y)
CALL CVDU_XY ; MOVE THE CURSOR
CALL CVDU_XY ; SET CURSOR POSITION
XOR A ; SIGNAL SUCCESS
RET
@ -194,10 +190,14 @@ CVDU_VDASCR1:
POP DE ; RECOVER E
INC E ; INCREMENT IT
JR CVDU_VDASCR ; LOOP
;
;======================================================================
; CVDU DRIVER - PRIVATE DRIVER FUNCTIONS
;======================================================================
;
;__CVDU_CRTINIT_____________________________________________________________________________________
;
; INIT 8563 VDU CHIP
;----------------------------------------------------------------------
; MOS 8563 DISPLAY CONTROLLER CHIP INITIALIZATION
;----------------------------------------------------------------------
;
CVDU_CRTINIT:
LD C,0 ; START WITH REGISTER 0
@ -211,18 +211,18 @@ CVDU_CRTINIT1:
DJNZ CVDU_CRTINIT1 ; LOOP
RET
;
;__CVDU_LOADFONT____________________________________________________________________________________
;----------------------------------------------------------------------
; LOAD FONT DATA
;----------------------------------------------------------------------
;
; LOAD SCREEN FONT
;__________________________________________________________________________________________________
CVDU_LOADFONT:
LD HL,$2000 ; START OF FONT BUFFER
LD C,18 ; SET BUFFER POINTER
LD C,18 ; UPDATE ADDRESS REGISTER PAIR
CALL CVDU_WRX ; DO IT
LD HL,CVDU_FONTDATA ; POINTER TO FONT DATA
LD DE,$2000 ; LENGTH OF FONT DATA
LD C,31 ; WRITE DATA
LD C,31 ; DATA REGISTER
CVDU_LOADFONT1:
LD A,(HL) ; LOAD NEXT BYTE OF FONT DATA
CALL CVDU_WR ; WRITE IT
@ -233,32 +233,12 @@ CVDU_LOADFONT1:
JR NZ,CVDU_LOADFONT1 ; LOOP TILL DONE
RET
;
;__CVDU_WREG________________________________________________________________________________________
;
; WRITE VALUE IN A TO REGISTER IN B
; B: REGISTER TO UPDATE
; A: VALUE TO WRITE
;__________________________________________________________________________________________________
CVDU_WREG:
PUSH AF ; STORE AF
CVDU_WREG1:
IN A,(CVDU_STAT) ; read address/status register
BIT 7,A ; if bit 7 = 1 than an update strobe has been occured
JR Z,CVDU_WREG1 ; wait for ready
LD A,B ;
OUT (CVDU_REG),A ; select register
CVDU_WREG2:
IN A,(CVDU_STAT) ; read address/status register
BIT 7,A ; if bit 7 = 1 than an update strobe has been occured
JR Z,CVDU_WREG2 ; wait for ready
POP AF ;
OUT (CVDU_DATA),A ; PUT DATA
RET
;
;__CVDU_WR__________________________________________________________________________________________
;----------------------------------------------------------------------
; UPDATE M8563 REGISTERS
; CVDU_WR WRITES VALUE IN A TO VDU REGISTER SPECIFIED IN C
; CVDU_WRX WRITES VALUE IN DE TO VDU REGISTER PAIR IN C, C+1
;----------------------------------------------------------------------
;
; WRITE VALUE IN A TO REGISTER IN C
;__________________________________________________________________________________________________
CVDU_WR:
PUSH AF ; SAVE VALUE TO WRITE
LD A,C ; SET A TO CVDU REGISTER TO SELECT
@ -271,10 +251,6 @@ CVDU_WR1:
OUT (CVDU_DATA),A ; WRITE IT
RET
;
;__CVDU_WRX_________________________________________________________________________________________
;
; WRITE VALUE IN HL TO REGISTER PAIR C/C+1
;__________________________________________________________________________________________________
CVDU_WRX:
LD A,H ; SETUP MSB TO WRITE
CALL CVDU_WR ; DO IT
@ -282,86 +258,90 @@ CVDU_WRX:
LD A,L ; SETUP LSB TO WRITE
JR CVDU_WR ; DO IT & RETURN
;
;__CVDU_GREG________________________________________________________________________________________
;
; GET VALUE FROM REGISTER IN B PLACE IN A
; B: REGISTER TO GET
; A: VALUE
;__________________________________________________________________________________________________
CVDU_GREG:
IN A,(CVDU_STAT) ; read address/status register
BIT 7,A ; if bit 7 = 1 than an update strobe has been occured
JR Z,CVDU_GREG ; wait for ready
LD A,B ;
OUT (CVDU_REG) , A ; select register
CVDU_GREG1:
IN A,(CVDU_STAT) ; read address/status register
BIT 7,A ; if bit 7 = 1 than an update strobe has been occured
JR Z,CVDU_GREG1 ; wait for ready
IN A,(CVDU_DATA) ; GET DATA
RET
;----------------------------------------------------------------------
; READ M8563 REGISTERS
; CVDU_RD READS VDU REGISTER SPECIFIED IN C AND RETURNS VALUE IN A
; CVDU_RDX READS VDU REGISTER PAIR SPECIFIED BY C, C+1
; AND RETURNS VALUE IN HL
;----------------------------------------------------------------------
;
CVDU_RD:
LD A,C ; SET A TO CVDU REGISTER TO SELECT
OUT (CVDU_REG),A ; WRITE IT TO SELECT THE REGISTER
CVDU_RD1:
IN A,(CVDU_STAT) ; GET CVDU STATUS
BIT 7,A ; CHECK BIT 7
JR Z,CVDU_WR1 ; LOOP WHILE NOT READY (BIT 7 NOT SET)
IN A,(CVDU_DATA) ; READ IT
RET
;
;__CVDU_XY__________________________________________________________________________________________
CVDU_RDX:
CALL CVDU_RD ; GET VALUE FROM REGISTER IN C
LD H,A ; SAVE IN H
INC C ; BUMP TO NEXT REGISTER OF PAIR
CALL CVDU_RD ; READ THE VALUE
LD L,A ; SAVE IT IN L
RET
;
; MOVE CURSOR TO POSITON IN CVDU_X AND CVDU_Y
;----------------------------------------------------------------------
; SET CURSOR POSITION TO ROW IN D AND COLUMN IN E
;----------------------------------------------------------------------
;
CVDU_XY:
LD A,(CVDU_Y) ; GET CURRENT ROW (Y)
LD H,A ; PLACE IN Y
LD DE,80 ; DE := 80 (ROW LENGTH)
CALL MULT8 ; HL := H * E (D IS CLEARED)
LD A,(CVDU_X) ; GET CURRENT COLUMN (X)
LD E,A ; PUT IN E, D IS ALREADY 0
ADD HL,DE ; ADD IN COLUMN OFFSET
LD (CVDU_DISPLAYPOS),HL ; SAVE THE RESULT (DISPLAY POSITION)
LD C,14 ; FUNCTION TO SET CURSOR POSITION
LD A,E ; SAVE COLUMN NUMBER IN A
LD H,D ; SET H TO ROW NUMBER
LD E,80 ; SET E TO ROW LENGTH
CALL MULT8 ; MULTIPLY TO GET ROW OFFSET
LD E,A ; GET COLUMN BACK
ADD HL,DE ; ADD IT IN
LD (CVDU_POS),HL ; SAVE THE RESULT (DISPLAY POSITION)
LD C,14 ; CURSOR POSITION REGISTER PAIR
JP CVDU_WRX ; DO IT AND RETURN
;
;__________________________________________________________________________________________________
CVDU_PUTCHAR:
;
; PLACE CHARACTER ON SCREEN, ADVANCE CURSOR
; A: CHARACTER TO OUTPUT
;----------------------------------------------------------------------
; WRITE VALULE IN A TO CURRENT VDU BUFFER POSTION, ADVANCE CURSOR
;----------------------------------------------------------------------
;
CVDU_PUTCHAR:
PUSH AF ; SAVE CHARACTER
; SET MEMORY LOCATION FOR CHARACTER
LD HL,(CVDU_DISPLAYPOS)
LD C,18
CALL CVDU_WRX
LD HL,(CVDU_POS) ; LOAD CURRENT POSITION INTO HL
LD C,18 ; UPDATE ADDRESS REGISTER PAIR
CALL CVDU_WRX ; DO IT
; PUT THE CHARACTER THERE
POP AF
LD C,31
CALL CVDU_WR
POP AF ; RECOVER CHARACTER VALLUE TO WRITE
LD C,31 ; DATA REGISTER
CALL CVDU_WR ; DO IT
; BUMP THE CURSOR FORWARD
INC HL
LD (CVDU_DISPLAYPOS),HL
LD C,14
CALL CVDU_WRX
INC HL ; BUMP HL TO NEXT POSITION
LD (CVDU_POS),HL ; SAVE IT
LD C,14 ; CURSOR POSITION REGISTER PAIR
CALL CVDU_WRX ; DO IT
; SET MEMORY LOCATION FOR ATTRIBUTE
LD DE,$800 - 1
ADD HL,DE
LD C,18
CALL CVDU_WRX
LD DE,$800 - 1 ; SETUP DE TO ADD OFFSET INTO ATTRIB BUFFER
ADD HL,DE ; HL NOW POINTS TO ATTRIB POS FOR CHAR JUST WRITTEN
LD C,18 ; UPDATE ADDRESS REGISTER PAIR
CALL CVDU_WRX ; DO IT
; PUT THE ATTRIBUTE THERE
LD A,(CVDU_ATTR)
LD C,31
JP CVDU_WR
;
;__________________________________________________________________________________________________
CVDU_FILL:
LD A,(CVDU_ATTR) ; LOAD THE ATTRIBUTE VALUE
LD C,31 ; DATA REGISTER
JP CVDU_WR ; DO IT AND RETURN
;
;----------------------------------------------------------------------
; FILL AREA IN BUFFER WITH SPECIFIED CHARACTER AND CURRENT COLOR/ATTRIBUTE
; STARTING WITH THE CURRENT FRAME BUFFER POSITION
; STARTING AT THE CURRENT FRAME BUFFER POSITION
; A: FILL CHARACTER
; DE: NUMBER OF CHARACTERS TO FILL
;----------------------------------------------------------------------
;
CVDU_FILL:
PUSH DE ; SAVE FILL COUNT
LD HL,(CVDU_DISPLAYPOS) ; SET CHARACTER BUFFER POSITION TO FILL
LD HL,(CVDU_POS) ; SET CHARACTER BUFFER POSITION TO FILL
PUSH HL ; SAVE BUF POS
CALL CVDU_FILL1 ; DO THE CHARACTER FILL
POP HL ; RECOVER BUF POS
@ -372,7 +352,6 @@ CVDU_FILL:
JR CVDU_FILL1 ; DO ATTRIBUTE FILL AND RETURN
CVDU_FILL1:
; SAVE FILL VALUE
LD B,A ; SAVE REQUESTED FILL VALUE
; CHECK FOR VALID FILL LENGTH
@ -381,44 +360,45 @@ CVDU_FILL1:
RET Z ; BAIL OUT IF LENGTH OF ZERO SPECIFIED
; POINT TO BUFFER LOCATION TO START FILL
LD C,18 ; USE CVDU REG 18/19 TO SET BUF LOC
LD C,18 ; UPDATE ADDRESS REGISTER PAIR
CALL CVDU_WRX ; DO IT
; SET MODE TO BLOCK WRITE
XOR A ; WRITE VALUE 0 (BIT 7 CLR FOR BLOCK WRITE)
LD C,24 ; TO CVDU REG 24
LD C,24 ; BLOCK MODE CONTROL REGISTER
CALL CVDU_RD ; GET CURRENT VALUE
AND $7F ; CLEAR BIT 7 FOR FILL MODE
CALL CVDU_WR ; DO IT
; SET CHARACTER TO WRITE (WRITES ONE CHARACTER)
LD A,B ; RECOVER FILL VALUE
LD C,31 ; USE CVDU REG 31 TO WRITE VALUE
LD C,31 ; DATA REGISTER
CALL CVDU_WR ; DO IT
DEC DE ; REFLECT ONE CHARACTER WRITTEN
; LOOP TO DO BULK WRITE
; LOOP TO DO BULK WRITE (UP TO 255 BYTES PER LOOP)
EX DE,HL ; NOW USE HL FOR COUNT
LD C,30 ; BYTE COUNT REGISTER
CVDU_FILL2:
LD A,H ; GET HIGH BYTE
OR A ; SET FLAGS
LD A,L ; PRESUME WE WILL WRITE L COUNT BYTES
JR Z,CVDU_FILL3 ; IF H WAS ZERO, READY TO WRITE L BYTES
LD A,$FF ; H WAS > 0, WRITE 255 BYTES
LD A,L ; PRESUME WE WILL WRITE L COUNT (ALL REMAINING) BYTES
JR Z,CVDU_FILL3 ; IF H WAS ZERO, WRITE L BYTES
LD A,$FF ; H WAS > 0, NEED MORE LOOPS, WRITE 255 BYTES
CVDU_FILL3:
CALL CVDU_WR ; DO IT
CALL CVDU_WR ; DO IT (SOURCE/DEST REGS AUTO INCREMENT)
LD D,0 ; CLEAR D
LD E,A ; SET E TO BYTES WRITTEN
SBC HL,DE ; SUBTRACT FROM HL
RET Z ; IF ZERO, WE ARE DONE
JR CVDU_FILL2 ; OTHERWISE, WRITE SOME MORE
;
;__CVDU_SCROLL_______________________________________________________________________________________
;
; SCROLL THE SCREEN FORWARD ONE LINE
;----------------------------------------------------------------------
; SCROLL ENTIRE SCREEN FORWARD BY ONE LINE (CURSOR POSITION UNCHANGED)
;----------------------------------------------------------------------
;
CVDU_SCROLL:
; SCROLL THE CHARACTER BUFFER
LD A,'=' ; CHAR VALUE TO FILL NEW EXPOSED LINE
LD A,' ' ; CHAR VALUE TO FILL NEW EXPOSED LINE
LD HL,0 ; SOURCE ADDRESS OF CHARACER BUFFER
CALL CVDU_SCROLL1 ; SCROLL CHARACTER BUFFER
@ -431,12 +411,13 @@ CVDU_SCROLL1:
PUSH AF ; SAVE FILL VALUE FOR NOW
; SET MODE TO BLOCK COPY
LD A,$80 ; SET BIT 7 FOR BLOCK COPY
LD C,24 ; IN CVDU REG 24
LD C,24 ; BLOCK MODE CONTROL REGISTER
CALL CVDU_RD ; GET CURRENT VALUE
OR $80 ; SET BIT 7 FOR COPY MODE
CALL CVDU_WR ; DO IT
; SET INITIAL BLOCK COPY DESTINATION (USING HL PASSED IN)
LD C,18 ; SET DESTINATION ADDRESS IN REG 18/19
LD C,18 ; UPDATE ADDRESS (DESTINATION) REGISTER
CALL CVDU_WRX ; DO IT
; COMPUTE SOURCE (INCREMENT ONE ROW)
@ -444,39 +425,40 @@ CVDU_SCROLL1:
ADD HL,DE ; ADD IT TO BUF ADDRESS
; SET INITIAL BLOCK COPY SOURCE
LD C,32 ; PUT THE SOURCE ADDRESS IN CVDU REG 32
LD C,32 ; BLOCK START ADDRESS REGISTER
CALL CVDU_WRX ; DO IT
LD B,23 ; ITERATIONS (23 ROWS)
LD B,23 ; ITERATIONS (ROWS - 1)
CVDU_SCROLL2:
; SET BLOCK COPY COUNT (WILL EXECUTE COPY)
LD A,80 ; COPY 80 BYTES
LD C,30 ; PUT LENGTH TO COPY IN REG 30
LD C,30 ; WORD COUNT REGISTER
CALL CVDU_WR ; DO IT
; LOOP TILL DONE WITH ALL LINES
DJNZ CVDU_SCROLL2 ; REPEAT FOR ALL LINES
; SET MODE TO BLOCK WRITE TO CLEAR NEW LINE EXPOSED BY SCROLL
XOR A ; CLR BIT 7
LD C,24 ; OF CVDU REG 24
CALL CVDU_WR
LD C,24 ; BLOCK MODE CONTROL REGISTER
CALL CVDU_RD ; GET CURRENT VALUE
AND $7F ; CLEAR BIT 7 FOR FILL MODE
CALL CVDU_WR ; DO IT
; SET CHARACTER TO WRITE
POP AF ; RESTORE THE FILL VALUE PASSED IN
LD C,31
CALL CVDU_WR
POP AF ; RESTORE THE FILL VALUE PASSED IN
LD C,31 ; DATA REGISTER
CALL CVDU_WR ; DO IT
; SET BLOCK WRITE COUNT (WILL EXECUTE THE WRITE)
LD A,80 - 1
LD C,30
CALL CVDU_WR
LD A,80 - 1 ; SET WRITE COUNT TO LINE LENGTH - 1 (1 CHAR ALREADY WRITTEN)
LD C,30 ; WORD COUNT REGISTER
CALL CVDU_WR ; DO IT
RET
;
;__CVDU_RSCROLL_______________________________________________________________________________________
;
; SCROLL THE SCREEN REVERSE ONE LINE
;----------------------------------------------------------------------
; REVERSE SCROLL ENTIRE SCREEN BY ONE LINE (CURSOR POSITION UNCHANGED)
;----------------------------------------------------------------------
;
CVDU_RSCROLL:
; SCROLL THE CHARACTER BUFFER
@ -487,21 +469,23 @@ CVDU_RSCROLL:
; SCROLL THE ATTRIBUTE BUFFER
LD A,(CVDU_ATTR) ; ATTRIBUTE VALUE TO FILL NEW EXPOSED LINE
LD HL,$800+(80*23) ; SOURCE ADDRESS OF ATTRIBUTE BUFFER (LINE 24)
JR CVDU_RSCROLL1 ; SCROLL ATTRIBUTE BUFFER
JR CVDU_RSCROLL1 ; SCROLL ATTRIBUTE BUFFER AND RETURN
CVDU_RSCROLL1:
PUSH AF ; SAVE FILL VALUE FOR NOW
; SET MODE TO BLOCK COPY
LD A,$80 ; SET BIT 7 FOR BLOCK COPY
LD C,24 ; IN CVDU REG 24
LD C,24 ; BLOCK MODE CONTROL REGISTER
CALL CVDU_RD ; GET CURRENT VALUE
AND $80 ; SET BIT 7 FOR COPY MODE
CALL CVDU_WR ; DO IT
; LOOP TO SCROLL EACH LINE WORKING FROM BOTTOM TO TOP
LD B,23 ; ITERATIONS (23 ROWS)
CVDU_RSCROLL2:
; SET BLOCK COPY DESTINATION (USING HL PASSED IN)
LD C,18 ; SET DESTINATION ADDRESS IN REG 18/19
LD C,18 ; UPDATE ADDRESS (DESTINATION) REGISTER
CALL CVDU_WRX ; DO IT
; COMPUTE SOURCE (DECREMENT ONE ROW)
@ -509,43 +493,40 @@ CVDU_RSCROLL2:
SBC HL,DE ; SUBTRACT IT FROM BUF ADDRESS
; SET BLOCK COPY SOURCE
LD C,32 ; PUT THE SOURCE ADDRESS IN CVDU REG 32
LD C,32 ; BLOCK START ADDRESS REGISTER
CALL CVDU_WRX ; DO IT
; SET BLOCK COPY COUNT (WILL EXECUTE COPY)
LD A,80 ; COPY 80 BYTES
LD C,30 ; PUT LENGTH TO COPY IN REG 30
LD C,30 ; WORD COUNT REGISTER
CALL CVDU_WR ; DO IT
; LOOP TILL DONE WITH ALL LINES
DJNZ CVDU_RSCROLL2 ; REPEAT FOR ALL LINES
; SET MODE TO BLOCK WRITE TO CLEAR NEW LINE EXPOSED BY SCROLL
XOR A ; CLR BIT 7
LD C,24 ; OF CVDU REG 24
CALL CVDU_WR
LD C,24 ; BLOCK MODE CONTROL REGISTER
CALL CVDU_RD ; GET CURRENT VALUE
AND $7F ; CLEAR BIT 7 FOR FILL MODE
CALL CVDU_WR ; DO IT
; SET CHARACTER TO WRITE
POP AF ; RESTORE THE FILL VALUE PASSED IN
LD C,31
CALL CVDU_WR
POP AF ; RESTORE THE FILL VALUE PASSED IN
LD C,31 ; DATA REGISTER
CALL CVDU_WR ; DO IT
; SET BLOCK WRITE COUNT (WILL EXECUTE THE WRITE)
LD A,80 - 1
LD C,30
CALL CVDU_WR
LD A,80 - 1 ; SET WRITE COUNT TO LINE LENGTH - 1 (1 CHAR ALREADY WRITTEN)
LD C,30 ; WORD COUNT REGISTER
CALL CVDU_WR ; DO IT
RET
;
;==================================================================================================
; VDU DRIVER - DATA
; CVDU DRIVER - DATA
;==================================================================================================
;
CVDU_X .DB 0 ; CURSOR X
CVDU_Y .DB 0 ; CURSOR Y
CVDU_ATTR .DB 0 ; CURRENT COLOR
CVDU_DISPLAYPOS .DW 0 ; CURRENT DISPLAY POSITION
CVDU_DISPLAY_START .DW 0 ; CURRENT DISPLAY POSITION
CVDU_POS .DW 0 ; CURRENT DISPLAY POSITION
;
; ATTRIBUTE ENCODING:
; BIT 7: ALTERNATE CHARACTER SET
@ -558,7 +539,7 @@ CVDU_DISPLAY_START .DW 0 ; CURRENT DISPLAY POSITION
; BIT 0: INTENSITY
;
;==================================================================================================
; VDU DRIVER - 8563 REGISTER INITIALIZATION
; CVDU DRIVER - 8563 REGISTER INITIALIZATION
;==================================================================================================
;
; Reg Hex Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Description
@ -606,7 +587,7 @@ CVDU_DISPLAY_START .DW 0 ; CURRENT DISPLAY POSITION
CVDU_INIT8563:
.DB 97 ; 0: hor. total - 1
.DB 80 ; 1: hor. displayed
.DB 85 ; 2: hor. sync position
.DB 90 ; 2: hor. sync position 85
.DB $14 ; 3: vert/hor sync width or 0x4F -- MDA
.DB 26 ; 4: vert total
.DB 2 ; 5: vert total adjust

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