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RomWBW/Source/n8v.asm

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; ../RomWBW/Source/n8v.asm 11/22/2012 dwg - best so far
; ../RomWBW/Source/n8v.asm 11/19/2012 dwg - add snippets into video scheme
; ../RomWBW/Source/n8v.asm 11/16/2012 dwg - N8V_VDAQRY now working
; ../RomWBW/Source/n8v.asm 11/15/2012 dwg - vdaini and vdaqry retcodes ok
; ../RomWBW/Source/n8v.asm 10/28/2012 dwg - add n8v_modes
; ../RomWBW/Source/n8v.asm 10/27/2012 dwg - begin enhancement
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; N8 VIDEO DRIVER FOR ROMWBW ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Video Display Processor I/O Addresses for the TMS9918 ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
BASE: .EQU 128
CMDP: .EQU BASE+25
DATAP: .EQU BASE+24
;__________________________________________________________________________________________________
; DATA CONSTANTS
;__________________________________________________________________________________________________
;
;_________________________________________________________________________
; BOARD INITIALIZATION
;_________________________________________________________________________
;
N8V_INIT:
PRTS("N8V:$")
LD HL,CHARSET
CALL N8V_VDAINI
XOR A
RET
;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; This routine is called from bnk1.asm to init the TMS9918 ;
; If HL is non-zero, it specifies the character bitmaps to load ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
N8V_VDAINI:
LD A,C
LD (VDP_DEVUNIT),A
LD A,E
LD (VDP_MODE),A
PUSH HL
; Fall through...
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; clear first 16K of TMS9918 video ram to zeroes ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
LD C,CMDP
LD A,$00
OUT (C),A ; out(CMDP,0);
CALL RECOVER
LD A,64
OUT (C),A ; out(CMDP,64);
CALL RECOVER
;
LD C,DATAP
LD HL,16384
CLR16LOOP:
LD A,0
OUT (C),A
DEC HL
LD A,H
OR L
JR NZ,CLR16LOOP
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Set TMS9918 into Text Mode ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
LD C,CMDP
LD A,0
OUT (C),A ; out(CMDP,0);
CALL RECOVER
LD A,128
OUT (C),A ; out(CMDP,128);
CALL RECOVER
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Set TMS9918 into 40-column mode ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
LD C,CMDP
LD A,80
OUT (C),A ; out(CMDP,80);
CALL RECOVER
LD A,129
OUT (C),A ; out(CMDP,129);
CALL RECOVER
;
;; text mode is 24x40
LD A,0
LD (VDP_MODE),a
LD a,40
LD (VDP_COLS),a
LD a,24
LD (VDP_ROWS),A
;; CALL VDP_PNT ; set TMS9918 Pattern Name Table Pointer
;VDP_PNT:
LD C,CMDP
LD A,0
OUT (C),A ; out(CMDP,0);
CALL RECOVER
LD A,130
OUT (C),A ; out(CMDP,130);
CALL RECOVER
;; CALL VDP_PGT ; set TMS9918 Pattern Generator Table Pointer
;VDP_PGT:
LD C,CMDP
LD A,1
OUT (C),A ; out(CMDP,1);
CALL RECOVER
LD A,132
OUT (C),A ; out(CMDP,132);
CALL RECOVER
;; CALL VDP_COLORS ; set TMS9918 foreground(white) background(black)
;VDP_COLORS:
LD C,CMDP
LD A,(VDP_ATTR)
; LD A,240
OUT (C),A ; out(CMDP,240); 240 is 0xF0 - 1111 0000 LSB=background MSB=foreground
CALL RECOVER
LD A,135
OUT (C),A ; out(CMDP,135);
CALL RECOVER
POP HL
LD A,L
OR H
JP Z,N8V_NOLOAD
;; CALL VDP_LOAD2 ; set TMS9918 character bitmaps
;VDP_LOAD2:
LD C,CMDP
LD A,0
OUT (C),A ; out(CMDP,0);
CALL RECOVER
LD A,72
OUT (C),A ; out(CMDP,72);
CALL RECOVER
LD DE,256
LD C,DATAP
VDP_LOAD2LOOP:
LD A,(HL)
LD (BYTE8),A
INC HL
LD A,(HL)
LD (BYTE7),A
INC HL
LD A,(HL)
LD (BYTE6),A
INC HL
LD A,(HL)
LD (BYTE5),A
INC HL
LD A,(HL)
LD (BYTE4),A
INC HL
LD A,(HL)
LD (BYTE3),A
INC HL
LD A,(HL)
LD (BYTE2),A
INC HL
LD A,(HL)
INC HL
OUT (C),A
CALL RECOVER
LD A,(BYTE2)
OUT (C),A
CALL RECOVER
LD A,(BYTE3)
OUT (C),A
CALL RECOVER
LD A,(BYTE4)
OUT (C),A
CALL RECOVER
LD A,(BYTE5)
OUT (C),A
CALL RECOVER
LD A,(BYTE6)
OUT (C),A
CALL RECOVER
LD A,(BYTE7)
OUT (C),A
CALL RECOVER
LD A,(BYTE8)
OUT (C),A
CALL RECOVER
DEC DE
LD A,D
OR E
JR NZ,VDP_LOAD2LOOP
N8V_NOLOAD:
; fall through...
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Display init message on composite video ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Output "N8-2312 TMS9918 Text Mode Init Done!"
LD HL,0
CALL VDP_WRVRAM
LD HL,VDP_HELLO
LD DE,39
LD C,DATAP
HELLO_LOOP:
LD A,(HL)
OUT (C),A
INC HL
DEC DE
LD A,D
OR E
JR NZ,HELLO_LOOP
;
; N8VEM HBIOS v2.2 B3
LD HL,40+40+40+40+3
CALL VDP_WRVRAM
LD HL,STR_BANNER
LD C,DATAP
LD DE,20
BAN_LOOP:
LD A,(HL)
CP '('
JP Z,BAN_DONE
OUT (C),A
INC HL
DEC DE
LD A,D
OR E
JR NZ,BAN_LOOP
BAN_DONE:
;
; (rOMwbw-DOUG-121113t0113) <BLANK>
LD HL,40+40+40+40+40+3
CALL VDP_WRVRAM
;
LD HL,STR_BANNER + 20
LD C,DATAP
;
LD DE,27
BAN_LOOP2:
LD A,(HL)
CP ' '
JP Z,BAN_DONE2
OUT (C),A
INC HL
DEC DE
LD A,D
OR E
JR NZ,BAN_LOOP2
LD A,'|'
OUT (C),A
CALL RECOVER
BAN_DONE2:
;
; n8 z180 sbc, floppy (autosize), ppide..
PUSH HL
LD HL,40+40+40+40+40+40+3
CALL VDP_WRVRAM
POP HL
;
LD C,DATAP
LD DE,60
BAN_LOOP3:
LD A,(HL)
CP '$'
JP Z,BAN_DONE3
OUT (C),A
INC HL
DEC DE
LD A,D
OR E
JP NZ,BAN_LOOP3
BAN_DONE3:
; fall through...
; WBW: PPK_INIT SHOULD ONLY BE CALLED FROM HBIOS INIT
; CALL PPK_INIT
; fall through...
XOR A
RET
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; This is the end of the init routine ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;__________________________________________________________________________________________________
; CHARACTER I/O (CIO) DISPATCHER
;__________________________________________________________________________________________________
;
N8V_DISPCIO:
LD A,B ; GET REQUESTED FUNCTION
AND $0F ; ISOLATE SUB-FUNCTION
JP Z,PPK_READ
DEC A
JR Z,N8V_CIOOUT
DEC A
JP Z,PPK_STAT
DEC A
JR Z,N8V_CIOOST
CALL PANIC
;
N8V_CIOOUT:
JP N8V_VDAWRC
;
N8V_CIOOST:
XOR A
INC A
RET
;
;__________________________________________________________________________________________________
; VIDEO DISPLAY ADAPTER (VDA) DISPATCHER
;__________________________________________________________________________________________________
;
N8V_DISPVDA:
LD A,B ; GET REQUESTED FUNCTION
AND $0F ; ISOLATE SUB-FUNCTION
JP Z,N8V_VDAINI
DEC A
JP Z,N8V_VDAQRY
DEC A
JP Z,N8V_VDARES
DEC A
JP Z,N8V_VDASCS
DEC A
JP Z,N8V_VDASCP
DEC A
JP Z,N8V_VDASAT
DEC A
JP Z,N8V_VDASCO
DEC A
JP Z,N8V_VDAWRC
DEC A
JP Z,N8V_VDAFIL
DEC A
JP Z,N8V_VDASCR
DEC A
JP Z,PPK_STAT
DEC A
JP Z,PPK_FLUSH
DEC A
JP Z,PPK_READ
CALL PANIC
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Video Display Processor Query ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
N8V_VDAQRY:
LD A,H
OR L
JP Z,N8V_QDONE
;
; read bitmaps and
LD C,CMDP
LD A,0
OUT (C),A ; out(CMDP,0);
CALL RECOVER
LD A,72
OUT (C),A ; out(CMDP,72);
CALL RECOVER
;
LD DE,256
LD C,DATAP
IN A,(C) ; read status
CALL RECOVER
VDP_QLOOP:
IN A,(C)
CALL RECOVER
LD (BYTE8),A
;
IN A,(C)
CALL RECOVER
LD (BYTE7),A
;
IN A,(C)
CALL RECOVER
LD (BYTE6),A
;
IN A,(C)
CALL RECOVER
LD (BYTE5),A
;
IN A,(C)
CALL RECOVER
LD (BYTE4),A
;
IN A,(C)
CALL RECOVER
LD (BYTE3),A
;
IN A,(C)
CALL RECOVER
LD (BYTE2),A
;
IN A,(C)
CALL RECOVER
; LD (BYTE1),A
;
LD (HL),A
INC HL
;
LD A,(BYTE2)
LD (HL),A
INC HL
;
LD A,(BYTE3)
LD (HL),A
INC HL
;
LD A,(BYTE4)
LD (HL),A
INC HL
;
LD A,(BYTE5)
LD (HL),A
INC HL
;
LD A,(BYTE6)
LD (HL),A
INC HL
;
LD A,(BYTE7)
LD (HL),A
INC HL
LD A,(BYTE8)
LD (HL),A
INC HL
DEC DE
LD A,D
OR E
JR NZ,VDP_QLOOP
N8V_QDONE:
LD A,(VDP_MODE)
LD C,A
LD A,(VDP_ROWS)
LD D,A
LD A,(VDP_COLS)
LD E,A
LD A,0 ; return SUCCESS
RET
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Video Display Processor Reset ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
N8V_VDARES:
LD HL,CHARSET
JP N8V_VDAINI
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Video Display Processor Set Cursor Style ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
N8V_VDASCS:
CALL PANIC
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Video Display Processor Set Cursor Position ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
N8V_VDASCP:
LD A,E
LD (VDP_COL),A ; keep private copy of column
LD A,C
LD (VDP_DEVUNIT),A ; keep private copy of dev/unit
LD A,D
LD (VDP_ROW),A ; keep private copy of row
XOR A
RET
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Video Display Processor Set Character Attributes ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
N8V_VDASAT:
CALL PANIC
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Video Display Processor Set Color Color ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
N8V_VDASCO:
CALL PANIC
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Video Display Processor Calculate Row Offset ;
; Enter with A = Row number (rel 0) ;
; returns with HL = offset ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
N8V_OFFSET:
PUSH DE
LD hl,row_offs ; hl -> row offset table
LD E,A ; place in LO byte of DE
LD d,0 ; make 16 bits
add hl,DE ;
add hl,DE ; hl -> word in offset table for desired row
LD e,(hl) ; pick up the LO byte of the row ptr
INC HL
ld d,(hl) ; pick up the HO byte of the ROW ptr
EX DE,HL ; hl -> offset of first column in row
POP DE
RET
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Video Display Processor Write Character ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
N8V_VDAWRC:
;;; LD (VDP_POS),HL ; accept curpos from caller in HL
PUSH DE
LD A,(VDP_ROW) ; pick up cursor row
LD E,A ; place in LO byte of DE
LD d,0 ; make 16 bits
add hl,DE ;
add hl,DE ; hl -> word in offset table for desired row
LD e,(hl) ; pick up the LO byte of the row ptr
INC HL
ld d,(hl) ; pick up the HO byte of the ROW ptr
EX DE,HL ; hl -> offset of first column in row
LD A,(VDP_COL) ; pick up the current column number
LD E,A ; use as LO byte of DE
LD D,0 ; make 16 bits
ADD HL,DE ; hl = offset in name table of row and column
call VDP_WRVRAM ; set vram write ptr to proper byte in name table
POP DE ; restore the output byte into E
LD A,E ; move into A for output
LD C,DATAP ; I/O address for subsequent VRAM write
OUT (C),a ; prime the auto incrementer
OUT (C),a ; output the data byte into the name table
XOR A ; set SUCCESS return code
RET ; return from HBIOS call
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Video Display Processor Fill ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
N8V_VDAFIL:
XOR A
RET
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Video Display Processor Scroll ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; COPY DATA ZONE FROM VRAM TO SCRLBUF
VDASCR_RVRAM:
; CALCULATE AND SET OFFSET TO START OF DATA ZONE IN VRAM
LD A,(VDASCR_DIST) ; from number lines to scroll,
CALL N8V_OFFSET ; set HL to offset of data in name table
CALL VDP_WRVRAM
; SETUP FOR VRAM DATA READ
LD C,DATAP ; using the TMS9918 data port
IN A,(C) ; PRIME AUTOINCREMENT
LD HL,SCRLBUF ; DEST IS SCRLBUF OFFSET 0
; COPY VDASCR_SIZE BYTES FROM VRAM TO HEAD OF SCRLBUF
LD DE,(VDASCR_SIZE) ; SIZE OF DATA ZONE
N8V_VDASCR2:
IN A,(C) ; FETCH NEXT BYTE FROM VRAM
LD (HL),A ; STORE IN SEQUENTIAL LOCATIONS IN SCRBUF
INC HL ; BUMP STORAGE INDEX
DEC DE ; DECREMENT BYTE COUNT REMAINING
LD A,D ; OR D
OR E ; WITH E
JR NZ,N8V_VDASCR2 ; AND DO MORE IF NOT ZERO
RET
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
VDASCR_WVRAM:
LD HL,0
CALL VDP_WRVRAM
LD C,DATAP
; OUT (C),A
LD HL,SCRLBUF
LD DE,(VDASCR_SIZE)
N8V_VDASCR3:
LD A,(HL) ; FETCH NEXT BYTE FROM SCRLBUF
OUT (C),A
INC HL
DEC DE
LD A,D
OR E
JR NZ,N8V_VDASCR3
RET
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
VDASCR_BLANKING:
; CALCULATE SIZE OF BLANKING ZONE
LD A,(VDASCR_DIST)
CALL N8V_OFFSET
EX DE,HL ; NUMBER OF BYTES TO BLANK
N8V_VDASCR4:
LD A,' ' ; WE WILL BE STORING BLANKS
OUT (C),A ; OUTPUT A BYTE TO THE VRAM NAME TABLE BLANKING ZONE
DEC DE ; DECREMENT COUNT
LD A,D ; OR THE HO BYTE
OR E ; WITH THE LO BYTE
JR NZ,N8V_VDASCR4 ; ;AND LOOP IF NOT ZERO
RET
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
VDASCR_DIST .DB 0 ; NUMBER OF ROWS TO SCROLL
VDASCR_SIZE .DW 0 ; SIZE IN BYTES OF DATA REGION
N8V_VDASCR:
; E = scroll distance (# lines)
LD A,E
LD (VDASCR_DIST),A
LD A,(VDP_ROWS) ; NUMBER OF ROWS ON SCREEN
SUB E ; MINUS DIST IS ROWS OF DATA
CALL N8V_OFFSET ; CVT ROWS OF DATA TO NUMBER OF BYTES
LD (VDASCR_SIZE),HL ; AND SAVE FOR LATER USE
CALL VDASCR_RVRAM ; read data region of name table into scrlbuf
CALL VDASCR_WVRAM ; write scrlbuf to head of name table in VRAM
CALL VDASCR_BLANKING ; blank dist lines at end of name table
XOR A ; SET SUCCESSFUL RETURN CODE
RET ; RETURN TO CALLER
SCRLBUF .db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
.db 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
;-------------------------------------------------
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Video Display Processor Write the VRAM address registers ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
VDP_WRVRAM:
; HL -> points to ram location
LD C,CMDP
OUT (C),L
CALL RECOVER
OUT (C),H
CALL RECOVER
RET
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Recovery-time delay routine - Conservatively long delay ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
RECOVER:
PUSH BC
PUSH DE
PUSH HL
POP HL
POP DE
POP BC
RET
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Video Display Processor Local Driver Data ;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
VDP_DEVUNIT .DB 0
; The following data items, VDP_COL and VDP_ROW area
; data bytes that can be retrieved together with a
; word fetch using the VDP_POS label. It is generally
; set by a call to VDASCP from the emulation layer.
; It is used by VDAFIL specifically to denote the beginning
; of the fill area not specified in the API of VDAFIL.
VDP_POS:
VDP_COL .DB 0 ; col number 0-39
VDP_ROW .DB 0 ; row number 0-23
VDP_ROWS .DB 24 ; number of rows
VDP_COLS .DB 40 ;
VDP_MODE .DB 0
VDP_ATTR .DB 240 ; default to white on black
VDP_HELLO .TEXT " N8-2312 TMS9918 Text Mode Init Done!!"
VDP_HELLOLEN .DB $-VDP_HELLO
BYTE1 .DB 0
BYTE2 .DB 0
BYTE3 .DB 0
BYTE4 .DB 0
BYTE5 .DB 0
BYTE6 .DB 0
BYTE7 .DB 0
BYTE8 .DB 0
CHARSET:
#INCLUDE "n8chars.inc"
row_offs .dw 40* 0,40* 1,40* 2,40* 3,40* 4,40* 5,40* 6,40* 7
.dw 40* 8,40* 9,40*10,40*11,40*12,40*13,40*14,40*15
.dw 40*16,40*17,40*18,40*19,40*20,40*21,40*22,40*23
;
;;;;;;;;;;;;;;;;;
; eof - n8v.asm ;
;;;;;;;;;;;;;;;;;