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;======================================================================
; VIDEO DRIVER FOR TRION VGA
; http://s100computers.com/My%20System%20Pages/FPGA%20Z80%20SBC/FPGA%20Z80%20SBC.htm
;
; WRITTEN BY: WAYNE WARTHEN -- 9/2/2024
;======================================================================
;
; TRION VGA EXPOSES A FRAME BUFFER STARTING AT $E000.
; PORT $08 CONTROLS ACCESS TO THE FRAME BUFFER.
; - WHEN $01, FRAME BUFFER APPEARS AT $E000 IN CPU ADDRESS SPACE
; - WHEN $00, FRAME BUFFER IS INACCESSIBLE BY CPU
; PORT $C0: SET/GET CURSOR COL
; PORT $C1: SET/GET CURSOR ROW
; PORT $C2: CONTROLS VGA OUTPUT
; BIT 0: BLUE
; BIT 1: GREEN
; BIT 2: RED
; BIT 3: UNUSED?
; BIT 4: CURSOR MODE
; BIT 5: CURSOR BLINK
; BIT 6: CURSOR ENABLE
; BIT 7: VGA SIGNAL OUTPUT ENABLE
; PORT $08: BUFFER SELECT, 1=SELECTED
;
; TODO:
;
;======================================================================
; TRION VGA DRIVER - CONSTANTS
;======================================================================
;
TVGA_FBUF .EQU $E000 ; ADDRESS OF FRAME BUFFER
TVGA_BASE .EQU $C0 ; BASE I/O ADDRESS
TVGA_CCOL .EQU TVGA_BASE+0 ; CUR COL PORT
TVGA_CROW .EQU TVGA_BASE+1 ; CUR ROW PORT
TVGA_CTL .EQU TVGA_BASE+2 ; VGA CONTROL PORT
;
TVGA_BUFCTL .EQU $08
;
TVGA_KBDDATA .EQU $03 ; KBD CTLR DATA PORT
TVGA_KBDST .EQU $02 ; KBD CTLR STATUS/CMD PORT
;
TVGA_ROWS .EQU 40
TVGA_COLS .EQU 80
;
TERMENABLE .SET TRUE ; INCLUDE TERMINAL PSEUDODEVICE DRIVER
KBDENABLE .SET TRUE ; INCLUDE KBD KEYBOARD SUPPORT
;
DEVECHO "TVGA: IO="
DEVECHO TVGA_BASE
DEVECHO ", KBD MODE=T35"
DEVECHO ", KBD IO="
DEVECHO TVGA_KBDDATA
DEVECHO "\n"
;
;======================================================================
; TRION VGA DRIVER - INITIALIZATION
;======================================================================
;
TVGA_INIT:
LD IY,TVGA_IDAT ; POINTER TO INSTANCE DATA
;
OR $FF ; CLEAR THE
LD (TVGA_UNIT),A ; ... UNIT NUMBER
;
CALL NEWLINE ; FORMATTING
PRTS("TVGA: IO=0x$")
LD A,TVGA_BASE
CALL PRTHEXBYTE
CALL TVGA_PROBE ; CHECK FOR HW PRESENCE
JR Z,TVGA_INIT1 ; CONTINUE IF HW PRESENT
;
; HARDWARE NOT PRESENT
PRTS(" NOT PRESENT$")
OR $FF ; SIGNAL FAILURE
RET
;
TVGA_INIT1:
;;; ; RECORD DRIVER ACTIVE
;;; OR $FF
;;; LD (TVGA_ACTIVE),A
; DISPLAY CONSOLE DIMENSIONS
LD A,TVGA_COLS
CALL PC_SPACE
CALL PRTDECB
LD A,'X'
CALL COUT
LD A,TVGA_ROWS
CALL PRTDECB
PRTS(" TEXT$")
; HARDWARE INITIALIZATION
CALL TVGA_CRTINIT ; SETUP THE TRION VGA REGISTERS
CALL TVGA_VDAINI ; INITIALIZE
CALL KBD_INIT ; INITIALIZE KEYBOARD DRIVER
; ADD OURSELVES TO VDA DISPATCH TABLE
LD BC,TVGA_FNTBL ; BC := FUNCTION TABLE ADDRESS
LD DE,TVGA_IDAT ; DE := TRION VGA INSTANCE DATA PTR
CALL VDA_ADDENT ; ADD ENTRY, A := UNIT ASSIGNED
; INITIALIZE EMULATION
LD C,A ; C := ASSIGNED VIDEO DEVICE NUM
LD DE,TVGA_FNTBL ; DE := FUNCTION TABLE ADDRESS
LD HL,TVGA_IDAT ; HL := TRION VGA INSTANCE DATA PTR
CALL TERM_ATTACH ; DO IT
CP $FF ; ERROR?
JR NZ,TVGA_INIT2 ; CONTINUE IF ALL GOOD
OR A ; IF ERROR, SET FLAGS
RET ; AND RETURN
TVGA_INIT2:
LD (TVGA_UNIT),A ; RECORD OUR UNIT NUMBER
XOR A ; SIGNAL SUCCESS
RET
;
;======================================================================
; TRION VGA DRIVER - VIDEO DISPLAY ADAPTER (VDA) FUNCTIONS
;======================================================================
;
TVGA_FNTBL:
.DW TVGA_VDAINI
.DW TVGA_VDAQRY
.DW TVGA_VDARES
.DW TVGA_VDADEV
.DW TVGA_VDASCS
.DW TVGA_VDASCP
.DW TVGA_VDASAT
.DW TVGA_VDASCO
.DW TVGA_VDAWRC
.DW TVGA_VDAFIL
.DW TVGA_VDACPY
.DW TVGA_VDASCR
.DW TVGA_STAT
.DW TVGA_FLUSH
.DW TVGA_READ
.DW TVGA_VDARDC
#IF (($ - TVGA_FNTBL) != (VDA_FNCNT * 2))
.ECHO "*** INVALID TVGA FUNCTION TABLE ***\n"
!!!!!
#ENDIF
TVGA_VDAINI:
; RESET VDA
CALL TVGA_VDARES ; RESET VDA
LD HL,0 ; ZERO
LD (TVGA_POS),HL ; ... TO POSITION
LD A,' ' ; BLANK THE SCREEN
LD DE,TVGA_ROWS*TVGA_COLS ; FILL ENTIRE BUFFER
CALL TVGA_FILL ; DO IT
LD DE,0 ; ROW = 0, COL = 0
CALL TVGA_XY ; SEND CURSOR TO TOP LEFT
CALL TVGA_SHOWCUR ; NOW SHOW THE CURSOR
XOR A ; SIGNAL SUCCESS
RET
TVGA_VDAQRY:
LD C,$00 ; MODE ZERO IS ALL WE KNOW
LD D,TVGA_ROWS ; ROWS
LD E,TVGA_COLS ; COLS
LD HL,0 ; EXTRACTION OF CURRENT BITMAP DATA NOT SUPPORTED
XOR A ; SIGNAL SUCCESS
RET
TVGA_VDARES:
CALL TVGA_CRTINIT
XOR A ; SIGNAL SUCCESS
RET
TVGA_VDADEV:
LD D,VDADEV_TVGA ; D := DEVICE TYPE
LD E,0 ; E := PHYSICAL UNIT IS ALWAYS ZERO
LD H,0 ; H := 0, DRIVER HAS NO MODES
LD L,TVGA_BASE ; L := BASE I/O ADDRESS
XOR A ; SIGNAL SUCCESS
RET
TVGA_VDASCS:
SYSCHKERR(ERR_NOTIMPL) ; NOT IMPLEMENTED (YET)
RET
TVGA_VDASCP:
CALL TVGA_XY ; SET CURSOR POSITION
XOR A ; SIGNAL SUCCESS
RET
TVGA_VDASAT:
; ATTRIBUTES NOT SUPPORTED BY HARDWARE
XOR A
RET
TVGA_VDASCO:
; CHARACTER COLOR NOT SUPPORT BY HARDWARE
XOR A ; SIGNAL SUCCESS
RET ; DONE
TVGA_VDAWRC:
LD A,E ; CHARACTER TO WRITE GOES IN A
CALL TVGA_PUTCHAR ; PUT IT ON THE SCREEN
XOR A ; SIGNAL SUCCESS
RET
TVGA_VDAFIL:
LD A,E ; FILL CHARACTER GOES IN A
EX DE,HL ; FILL LENGTH GOES IN DE
CALL TVGA_FILL ; DO THE FILL
XOR A ; SIGNAL SUCCESS
RET
TVGA_VDACPY:
; LENGTH IN HL, SOURCE ROW/COL IN DE, DEST IS TVGA_POS
; BLKCPY USES: HL=SOURCE, DE=DEST, BC=COUNT
PUSH HL ; SAVE LENGTH
CALL TVGA_XY2IDX ; ROW/COL IN DE -> SOURCE ADR IN HL
POP BC ; RECOVER LENGTH IN BC
LD DE,(TVGA_POS) ; PUT DEST IN DE
JP TVGA_BLKCPY ; DO A BLOCK COPY
TVGA_VDASCR:
LD A,E ; LOAD E INTO A
OR A ; SET FLAGS
RET Z ; IF ZERO, WE ARE DONE
PUSH DE ; SAVE E
JP M,TVGA_VDASCR1 ; E IS NEGATIVE, REVERSE SCROLL
CALL TVGA_SCROLL ; SCROLL FORWARD ONE LINE
POP DE ; RECOVER E
DEC E ; DECREMENT IT
JR TVGA_VDASCR ; LOOP
TVGA_VDASCR1:
CALL TVGA_RSCROLL ; SCROLL REVERSE ONE LINE
POP DE ; RECOVER E
INC E ; INCREMENT IT
JR TVGA_VDASCR ; LOOP
TVGA_STAT:
IN A,(TVGA_KBDST) ; GET STATUS
AND $01 ; ISOLATE DATA WAITING BIT
JP Z,CIO_IDLE ; NO DATA, EXIT VIA IDLE PROCESS
RET
TVGA_FLUSH:
XOR A ; SIGNAL SUCCESS
RET
TVGA_READ:
CALL TVGA_STAT ; GET STATUS
JR Z,TVGA_READ ; LOOP TILL DATA READY
IN A,(TVGA_KBDDATA) ; GET BYTE
LD E,A ; PUT IN E FOR RETURN
XOR A ; SIGNAL SUCCESS
RET ; DONE
;----------------------------------------------------------------------
; READ VALUE AT CURRENT VDU BUFFER POSITION
; RETURN E = CHARACTER, B = COLOUR, C = ATTRIBUTES
;----------------------------------------------------------------------
TVGA_VDARDC:
CALL TVGA_GETCHAR ; GET THE CHARACTER AT CUR CUR POS
LD E,A ; PUT IN E
LD BC,0 ; COLOR AND ATTR NOT SUPPORTED
XOR A ; SIGNAL SUCCESS
RET
;
;======================================================================
; TRION VGA DRIVER - PRIVATE DRIVER FUNCTIONS
;======================================================================
;
;
;----------------------------------------------------------------------
; PROBE FOR TRION VGA HARDWARE
;----------------------------------------------------------------------
;
; ON RETURN, ZF SET INDICATES HARDWARE FOUND
;
TVGA_PROBE:
XOR A ; ASSUME H/W EXISTS
RET
;
;----------------------------------------------------------------------
; CRTC DISPLAY CONTROLLER CHIP INITIALIZATION
;----------------------------------------------------------------------
;
TVGA_CRTINIT:
LD A,%11001111 ; WHITE ON BLACK, CURSOR ON, ENABLE OUTPUT
OUT (TVGA_CTL),A ; WRITE TO CONTROL PORT
XOR A ; ZERO ACCUM
RET ; DONE
;
;----------------------------------------------------------------------
; SET CURSOR POSITION TO ROW IN D AND COLUMN IN E
;----------------------------------------------------------------------
;
TVGA_XY:
CALL TVGA_HIDECUR ; HIDE THE CURSOR
PUSH DE ; SAVE NEW POSITION FOR NOW
CALL TVGA_XY2IDX ; CONVERT ROW/COL TO BUF IDX
LD (TVGA_POS),HL ; SAVE THE RESULT (DISPLAY POSITION)
POP DE ; RECOVER INCOMING ROW/COL
LD A,D ; GET ROW
OUT (TVGA_CROW),A ; SET ROW REGISTER
LD A,E ; GET COL
INC A ; 1..79,0 (WHY???)
CP 80 ; COL 80?
JR NZ, TVGA_XY1 ; SKIP IF NOT
XOR A ; ELSE MAKE IT ZERO!
TVGA_XY1:
OUT (TVGA_CCOL),A ; SET COL REGISTER
JP TVGA_SHOWCUR ; SHOW THE CURSOR AND EXIT
;
;----------------------------------------------------------------------
; CONVERT XY COORDINATES IN DE INTO LINEAR INDEX IN HL
; D=ROW, E=COL
;----------------------------------------------------------------------
;
TVGA_XY2IDX:
LD A,E ; SAVE COLUMN NUMBER IN A
LD H,D ; SET H TO ROW NUMBER
LD E,TVGA_COLS ; SET E TO ROW LENGTH
CALL MULT8 ; MULTIPLY TO GET ROW OFFSET, H * E = HL, E=0, B=0
LD E,A ; GET COLUMN BACK
ADD HL,DE ; ADD IT IN
RET ; RETURN
;
;----------------------------------------------------------------------
; SHOW OR HIDE CURSOR
;----------------------------------------------------------------------
;
TVGA_SHOWCUR:
LD A,%11001111 ; CONTROL PORT VALUE
;;;LD A,%11111111 ; CONTROL PORT VALUE
OUT (TVGA_CTL),A ; SET REGISTER
XOR A ; SIGNAL SUCCESS
RET ; DONE
;
TVGA_HIDECUR:
LD A,%11001111 ; CONTROL PORT VALUE
;;;LD A,%11111111 ; CONTROL PORT VALUE
OUT (TVGA_CTL),A ; SET REGISTER
XOR A ; SIGNAL SUCCESS
RET ; DONE
;
;----------------------------------------------------------------------
; (DE)SELECT FRAME BUFFER
;----------------------------------------------------------------------
;
TVGA_BUFSEL:
PUSH AF
LD A,$01
OUT (TVGA_BUFCTL),A
POP AF
RET
;
TVGA_BUFDESEL:
PUSH AF
XOR A
OUT (TVGA_BUFCTL),A
POP AF
RET
;
;----------------------------------------------------------------------
; WRITE VALUE IN A TO CURRENT VDU BUFFER POSITION, ADVANCE CURSOR
;----------------------------------------------------------------------
;
TVGA_PUTCHAR:
; WRITE CHAR AT CURRENT CURSOR POSITION.
PUSH AF ; SAVE INCOMING CHAR
CALL TVGA_HIDECUR ; HIDE CURSOR
CALL TVGA_BUFSEL ; SELECT FRAME BUFFER
POP AF
LD HL,(TVGA_POS) ; GET CUR BUF POSITION
LD DE,TVGA_FBUF ; START OF FRAME BUF
ADD HL,DE ; ADD IT IN
LD (HL),A ; PUT THE CHAR
;
; SET NEW POSITION
LD HL,(TVGA_POS) ; GET POSITION
INC HL ; BUMP POSITION
LD (TVGA_POS),HL ; SAVE NEW POSITION
;
; PUT CUROR IN PLACE
LD DE,TVGA_COLS ; COLS PER LINE
CALL DIV16 ; BC=ROW, HL=COL
LD D,C
LD E,L
CALL TVGA_XY
CALL TVGA_BUFDESEL ; DESELECT FRAME BUFFER
JP TVGA_SHOWCUR ; SHOW IT AND RETURN
;
;----------------------------------------------------------------------
; GET CHAR VALUE TO A FROM CURRENT VDU BUFFER POSITION
;----------------------------------------------------------------------
;
TVGA_GETCHAR:
XOR A
RET
;
;----------------------------------------------------------------------
; FILL AREA IN BUFFER WITH SPECIFIED CHARACTER AND CURRENT COLOR/ATTRIBUTE
; STARTING AT THE CURRENT FRAME BUFFER POSITION
; A: FILL CHARACTER
; DE: NUMBER OF CHARACTERS TO FILL
;----------------------------------------------------------------------
;
TVGA_FILL:
PUSH AF ; SAVE INCOMING FILL CHAR
CALL TVGA_HIDECUR ; HIDE CURSOR
CALL TVGA_BUFSEL ; SELECT BUFFER
LD HL,(TVGA_POS) ; CUR POS TO HL
LD BC,TVGA_FBUF ; ADR OF FRAME
ADD HL,BC ; ADD IT IN
POP AF
LD C,A ; FILL CHAR TO C
TVGA_FILL1:
LD A,D ; CHECK FILL
OR E ; ... COUNTER
JR Z,TVGA_FILL2 ; DONE IF ZERO
LD (HL),C ; FILL ONE CHAR
INC HL ; BUMP BUF PTR
DEC DE ; DEC FILL COUNTER
JR TVGA_FILL1 ; LOOP
;
TVGA_FILL2:
CALL TVGA_BUFDESEL ; DESELECT BUFFER
JP TVGA_SHOWCUR ; EXIT VIA SHOW CURSOR
;
;----------------------------------------------------------------------
; SCROLL ENTIRE SCREEN FORWARD BY ONE LINE (CURSOR POSITION UNCHANGED)
;----------------------------------------------------------------------
;
TVGA_SCROLL:
CALL TVGA_BUFSEL ; SELECT FRAME BUFFER
;
; COPY "UP" ONE LINE
LD HL,TVGA_FBUF + TVGA_COLS ; FROM SECOND LINE
LD DE,TVGA_FBUF ; TO FIRST LINE
LD BC,+(TVGA_ROWS - 1) * TVGA_COLS ; ALL BUT ONE LINE
LDIR ; DO IT
;
; FILL LAST LINE OF SCREEN
LD HL,TVGA_FBUF + ((TVGA_ROWS - 1) * TVGA_COLS) ; LAST LINE
LD A,' ' ; FILL CHAR
LD (HL),A ; COPY 1 CHAR
LD DE,TVGA_FBUF + ((TVGA_ROWS - 1) * TVGA_COLS) + 1 ; SECOND POS IN LAST LINE
LD BC,TVGA_COLS - 1 ; COLS PER LINE - 1
LDIR ; FILL IT
;
CALL TVGA_BUFDESEL ; DESELECT FRAME BUFFER
RET ; DONE
;
;----------------------------------------------------------------------
; REVERSE SCROLL ENTIRE SCREEN BY ONE LINE (CURSOR POSITION UNCHANGED)
;----------------------------------------------------------------------
;
TVGA_RSCROLL:
CALL TVGA_BUFSEL ; SELECT FRAME BUFFER
;
; COPY "DOWN" ONE LINE
LD HL,TVGA_FBUF + (TVGA_COLS * (TVGA_ROWS - 1)) - 1 ; FROM END OF SECOND TO LAST LINE
LD DE,TVGA_FBUF + (TVGA_COLS * TVGA_ROWS) - 1 ; TO END OF LAST LINE
LD BC,+(TVGA_ROWS - 1) * TVGA_COLS ; ALL BUT ONE LINE
LDDR ; DO IT IN REVERSE
;
; FILL FIRST LINE OF SCREEN
LD HL,TVGA_FBUF ; FIRST LINE
LD A,' ' ; FILL CHAR
LD (HL),A ; COPY 1 CHAR
LD DE,TVGA_FBUF + 1 ; SECOND POS IN FIRST LINE
LD BC,TVGA_COLS - 1 ; COLS PER LINE - 1
LDIR ; FILL IT
;
CALL TVGA_BUFDESEL ; DESELECT FRAME BUFFER
RET ; DONE
;
;----------------------------------------------------------------------
; BLOCK COPY BC BYTES FROM HL TO DE
;----------------------------------------------------------------------
;
TVGA_BLKCPY:
CALL TVGA_BUFSEL ; SELECT FRAME BUFFER
PUSH BC ; SAVE LENGTH
LD BC,TVGA_FBUF ; FRAME BUFFER ADR
ADD HL,BC ; ADD TO SOURCE
EX DE,HL ; EXCHANGE
ADD HL,BC ; ADD TO DEST
EX DE,HL ; EXCHANGE
POP BC ; RECOVER LENGTH
LDIR ; LDIR DOES THE COPY
CALL TVGA_BUFDESEL ; DESELECT FRAME BUFFER
RET ; DONE
;
;==================================================================================================
; TRION VGA DRIVER - DATA
;==================================================================================================
;
TVGA_POS .DW 0 ; CURRENT DISPLAY POSITION
;;;TVGA_ACTIVE .DB FALSE ; FLAG FOR DRIVER ACTIVE
TVGA_UNIT .DB $FF ; ASSIGNED UNIT NUMBER
;
;==================================================================================================
; VGA DRIVER - INSTANCE DATA
;==================================================================================================
;
TVGA_IDAT:
.DB KBDMODE_T35 ; S100 T35 KEYBOARD CONTROLLER
.DB TVGA_KBDST
.DB TVGA_KBDDATA