mirror of
https://github.com/wwarthen/RomWBW.git
synced 2026-02-06 14:11:48 -06:00
9358299f14
Z280 is having an issue with OTDR instruction when loading the font for VGARC. For now, the use of OTDR has been eliminated.
671 lines
18 KiB
NASM
671 lines
18 KiB
NASM
;======================================================================
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; VIDEO DRIVER FOR VGARC
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; https://www.retrobrewcomputers.org/doku.php?id=builderpages:plasmo:vgarc1:vgarc1home
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;
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; WRITTEN BY: WAYNE WARTHEN -- 5/1/2023
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;======================================================================
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;
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; TODO:
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;
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;======================================================================
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; VGARC DRIVER - CONSTANTS
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;======================================================================
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;
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VRC_BASE .EQU $00 ; FIRST CHAR DATA PORT
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VRC_FONTBASE .EQU VRC_BASE + $0C ; FIRST FONT PORT
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VRC_SCROLLIO .EQU $F5 ; SCROLL REG PORT
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;
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VRC_KBDDATA .EQU $F4
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VRC_KBDST .EQU $F5
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;
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VRC_ROWS .EQU 48
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VRC_COLS .EQU 64
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;
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#DEFINE USEFONTVGARC
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#DEFINE VRC_FONT FONTVGARC
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;
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TERMENABLE .SET TRUE ; INCLUDE TERMINAL PSEUDODEVICE DRIVER
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;
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;======================================================================
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; VRC DRIVER - INITIALIZATION
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;======================================================================
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;
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VRC_INIT:
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LD IY,VRC_IDAT ; POINTER TO INSTANCE DATA
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;
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CALL NEWLINE ; FORMATTING
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PRTS("VRC: IO=0x$")
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LD A,VRC_BASE
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CALL PRTHEXBYTE
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CALL VRC_PROBE ; CHECK FOR HW PRESENCE
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JR Z,VRC_INIT1 ; CONTINUE IF HW PRESENT
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;
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; HARDWARE NOT PRESENT
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PRTS(" NOT PRESENT$")
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OR $FF ; SIGNAL FAILURE
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RET
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;
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VRC_INIT1:
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; RECORD DRIVER ACTIVE
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OR $FF
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LD (VRC_ACTIVE),A
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; DISPLAY CONSOLE DIMENSIONS
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LD A,VRC_COLS
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CALL PC_SPACE
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CALL PRTDECB
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LD A,'X'
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CALL COUT
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LD A,VRC_ROWS
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CALL PRTDECB
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PRTS(" TEXT$")
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; HARDWARE INITIALIZATION
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CALL VRC_CRTINIT ; SETUP THE VGARC CHIP REGISTERS
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CALL VRC_LOADFONT ; LOAD FONT DATA FROM ROM TO VGARC STORAGE
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CALL VRC_VDARES ; RESET
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CALL KBD_INIT ; INITIALIZE KEYBOARD DRIVER
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; ADD OURSELVES TO VDA DISPATCH TABLE
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LD BC,VRC_FNTBL ; BC := FUNCTION TABLE ADDRESS
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LD DE,VRC_IDAT ; DE := VGARC INSTANCE DATA PTR
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CALL VDA_ADDENT ; ADD ENTRY, A := UNIT ASSIGNED
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; INITIALIZE EMULATION
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LD C,A ; C := ASSIGNED VIDEO DEVICE NUM
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LD DE,VRC_FNTBL ; DE := FUNCTION TABLE ADDRESS
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LD HL,VRC_IDAT ; HL := VGARC INSTANCE DATA PTR
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CALL TERM_ATTACH ; DO IT
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XOR A ; SIGNAL SUCCESS
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RET
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;
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;======================================================================
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; VGARC DRIVER - VIDEO DISPLAY ADAPTER (VDA) FUNCTIONS
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;======================================================================
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;
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VRC_FNTBL:
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.DW VRC_VDAINI
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.DW VRC_VDAQRY
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.DW VRC_VDARES
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.DW VRC_VDADEV
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.DW VRC_VDASCS
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.DW VRC_VDASCP
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.DW VRC_VDASAT
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.DW VRC_VDASCO
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.DW VRC_VDAWRC
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.DW VRC_VDAFIL
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.DW VRC_VDACPY
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.DW VRC_VDASCR
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.DW KBD_STAT
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.DW KBD_FLUSH
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.DW KBD_READ
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.DW VRC_VDARDC
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#IF (($ - VRC_FNTBL) != (VDA_FNCNT * 2))
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.ECHO "*** INVALID VRC FUNCTION TABLE ***\n"
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!!!!!
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#ENDIF
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VRC_VDAINI:
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; RESET VDA
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; CURRENTLY IGNORES VIDEO MODE AND BITMAP DATA
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CALL VRC_VDARES ; RESET VDA
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XOR A ; SIGNAL SUCCESS
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RET
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VRC_VDAQRY:
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LD C,$00 ; MODE ZERO IS ALL WE KNOW
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LD D,VRC_ROWS ; ROWS
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LD E,VRC_COLS ; COLS
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LD HL,0 ; EXTRACTION OF CURRENT BITMAP DATA NOT SUPPORTED YET
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XOR A ; SIGNAL SUCCESS
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RET
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VRC_VDARES:
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XOR A ; CLEAR ATTRIBUTES (REV VIDEO OFF)
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LD (VRC_ATTR),A ; SAVE IT
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DEC A ; INIT CUR NESTING, INIT TO HIDDEN
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LD (VRC_CURSOR),A ; SAVE IT
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LD HL,0 ; ZERO THE SCROLL OFFSET
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LD (VRC_OFF),HL ; SAVE VALUE
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XOR A ; ZERO
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LD (VRC_LOFF),A ; SCROLL OFFSET (LINES)
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LD A,' ' ; BLANK THE SCREEN
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LD DE,VRC_ROWS*VRC_COLS ; FILL ENTIRE BUFFER
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CALL VRC_FILL ; DO IT
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LD DE,0 ; ROW = 0, COL = 0
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CALL VRC_XY ; SEND CURSOR TO TOP LEFT
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CALL VRC_SHOWCUR ; NOW SHOW THE CURSOR
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;
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XOR A ; SIGNAL SUCCESS
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RET
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VRC_VDADEV:
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LD D,VDADEV_VRC ; D := DEVICE TYPE
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LD E,0 ; E := PHYSICAL UNIT IS ALWAYS ZERO
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LD H,0 ; H := 0, DRIVER HAS NO MODES
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LD L,VRC_BASE ; L := BASE I/O ADDRESS
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XOR A ; SIGNAL SUCCESS
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RET
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VRC_VDASCS:
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SYSCHKERR(ERR_NOTIMPL) ; NOT IMPLEMENTED (YET)
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RET
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VRC_VDASCP:
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CALL VRC_XY ; SET CURSOR POSITION
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XOR A ; SIGNAL SUCCESS
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RET
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VRC_VDASAT:
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; INCOMING IS: -----RUB (R=REVERSE, U=UNDERLINE, B=BLINK)
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;
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; ALL WE SUPPORT IS REVERSE. MOVE BIT TO BIT 7 OF ATTR BYTE
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LD A,E ; GET ATTR VALUE
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RRCA ; ROTATE TO BIT 7
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RRCA
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RRCA
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AND $80 ; ENSURE ONLY BIT 7
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LD (VRC_ATTR),A ; SAVE IT
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XOR A ; SIGNAL SUCCESS
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RET ; DONE
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VRC_VDASCO:
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; INCOMING IS: IBGRIBGR (I=INTENSITY, B=BLUE, G=GREEN, R=RED)
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;
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; NONE SUPPORTED, IGNORE
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XOR A ; SIGNAL SUCCESS
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RET ; DONE
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VRC_VDAWRC:
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LD A,E ; CHARACTER TO WRITE GOES IN A
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CALL VRC_PUTCHAR ; PUT IT ON THE SCREEN
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XOR A ; SIGNAL SUCCESS
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RET
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VRC_VDAFIL:
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LD A,E ; FILL CHARACTER GOES IN A
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EX DE,HL ; FILL LENGTH GOES IN DE
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CALL VRC_FILL ; DO THE FILL
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XOR A ; SIGNAL SUCCESS
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RET
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VRC_VDACPY:
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; LENGTH IN HL, SOURCE ROW/COL IN DE, DEST IS VRC_POS
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; BLKCPY USES: HL=SOURCE, DE=DEST, BC=COUNT
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PUSH HL ; SAVE LENGTH
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CALL VRC_XY2IDX ; ROW/COL IN DE -> SOURCE ADR IN HL
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POP BC ; RECOVER LENGTH IN BC
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LD DE,(VRC_POS) ; PUT DEST IN DE
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JP VRC_BLKCPY ; DO A BLOCK COPY
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VRC_VDASCR:
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LD A,E ; LOAD E INTO A
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OR A ; SET FLAGS
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RET Z ; IF ZERO, WE ARE DONE
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PUSH DE ; SAVE E
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JP M,VRC_VDASCR1 ; E IS NEGATIVE, REVERSE SCROLL
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CALL VRC_SCROLL ; SCROLL FORWARD ONE LINE
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POP DE ; RECOVER E
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DEC E ; DECREMENT IT
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JR VRC_VDASCR ; LOOP
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VRC_VDASCR1:
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CALL VRC_RSCROLL ; SCROLL REVERSE ONE LINE
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POP DE ; RECOVER E
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INC E ; INCREMENT IT
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JR VRC_VDASCR ; LOOP
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;----------------------------------------------------------------------
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; READ VALUE AT CURRENT VDU BUFFER POSITION
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; RETURN E = CHARACTER, B = COLOUR, C = ATTRIBUTES
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;----------------------------------------------------------------------
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VRC_VDARDC:
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OR $FF ; UNSUPPORTED FUNCTION
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RET
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;
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;======================================================================
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; VGARC DRIVER - PRIVATE DRIVER FUNCTIONS
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;======================================================================
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;
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;
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;----------------------------------------------------------------------
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; PROBE FOR VGARC HARDWARE
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;----------------------------------------------------------------------
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;
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; ON RETURN, ZF SET INDICATES HARDWARE FOUND
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;
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VRC_PROBE:
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LD C,VRC_BASE + 1 ; +1 AVOIDS LEDS
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LD B,$00
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LD A,$AA
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OUT (C),A
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INC B
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LD A,$55
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OUT (C),A
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DEC B
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IN A,(C)
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CP $AA
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RET NZ
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INC B
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IN A,(C)
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CP $55
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RET
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;
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;----------------------------------------------------------------------
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; CRTC DISPLAY CONTROLLER CHIP INITIALIZATION
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;----------------------------------------------------------------------
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;
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VRC_CRTINIT:
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XOR A ; ZERO ACCUM
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LD A,$80 ; ACTIVATE AND ZERO HW SCROLL
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OUT (VRC_SCROLLIO),A ; RESET HW SCROLL
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RET ; DONE
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;
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;----------------------------------------------------------------------
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; LOAD FONT DATA
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;----------------------------------------------------------------------
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;
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VRC_LOADFONT:
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;
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#IF USELZSA2
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LD (VRC_STACK),SP ; SAVE STACK
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LD HL,(VRC_STACK) ; AND SHIFT IT
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LD DE,$2000 ; DOWN 4KB TO
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OR A ; CREATE A
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SBC HL,DE ; DECOMPRESSION BUFFER
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LD SP,HL ; HL POINTS TO BUFFER
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EX DE,HL ; START OF STACK BUFFER
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PUSH DE ; SAVE IT
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LD HL,VRC_FONT ; START OF FONT DATA
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CALL DLZSA2 ; DECOMPRESS TO DE
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POP HL ; RECALL STACK BUFFER POSITION
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#ELSE
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LD HL,VRC_FONT ; START OF FONT DATA
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#ENDIF
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;
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#IF 0
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; THIS APPROACH TO LOADING FONTS IS BEST (FASTEST), BUT IS
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; CAUSING ARTIFACTS ON THE DISPLAYED FONTS WHEN RUN ON A
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; Z280. IT IS NOT CLEAR WHAT THE PROBLEM IS (POSSIBLY
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; Z280 BUG), BUT FOR NOW WE AVOID THIS AND USE AN
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; ALTERNATIVE APPROACH BELOW.
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LD DE,0+(128*8)-1 ; LENGTH OF FONT DATA - 1
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ADD HL,DE ; ADD TO HL
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LD BC,VRC_FONTBASE+3 ; WORK BACKWARDS
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OTDR ; DO 4 PAGES
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DEC C
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OTDR
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DEC C
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OTDR
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DEC C
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OTDR
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DEC C
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#ENDIF
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;
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#IF 1
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; ALTERNATIVE APPROACH TO LOADING FONTS. THIS ONE AVOIDS
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; THE USE OF OTDR WHICH SEEMS TO CAUSE PROBLEMS ON Z280.
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LD B,0
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LD C,VRC_FONTBASE
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VRC_LOADFONT1:
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LD A,(HL)
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OUT (C),A
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INC HL
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INC B
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JR NZ,VRC_LOADFONT1
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INC C
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LD A,C
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CP VRC_FONTBASE + 4
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JR NZ,VRC_LOADFONT1
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#ENDIF
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;
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#IF USELZSA2
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LD HL,(VRC_STACK) ; ERASE DECOMPRESS BUFFER
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LD SP,HL ; BY RESTORING THE STACK
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RET ; DONE
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VRC_STACK .DW 0
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#ELSE
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RET
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#ENDIF
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;
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;----------------------------------------------------------------------
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; SET CURSOR POSITION TO ROW IN D AND COLUMN IN E
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;----------------------------------------------------------------------
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;
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VRC_XY:
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PUSH DE ; SAVE NEW POSITION FOR NOW
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CALL VRC_HIDECUR ; HIDE THE CURSOR
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POP DE ; RECOVER INCOMING ROW/COL
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CALL VRC_XY2IDX ; CONVERT ROW/COL TO BUF IDX
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LD (VRC_POS),HL ; SAVE THE RESULT (DISPLAY POSITION)
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JP VRC_SHOWCUR ; SHOW THE CURSOR AND EXIT
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;
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;----------------------------------------------------------------------
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; CONVERT XY COORDINATES IN DE INTO LINEAR INDEX IN HL
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; D=ROW, E=COL
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;----------------------------------------------------------------------
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;
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VRC_XY2IDX:
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LD A,E ; SAVE COLUMN NUMBER IN A
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LD H,D ; SET H TO ROW NUMBER
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LD E,VRC_COLS ; SET E TO ROW LENGTH
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CALL MULT8 ; MULTIPLY TO GET ROW OFFSET, H * E = HL, E=0, B=0
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LD E,A ; GET COLUMN BACK
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ADD HL,DE ; ADD IT IN
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LD DE,(VRC_OFF) ; SCREEN OFFSET
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ADD HL,DE ; ADJUST
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;
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PUSH HL ; SAVE IT
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LD DE,VRC_ROWS * VRC_COLS ; DE := BUF SIZE
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OR A ; CLEAR CARRY
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SBC HL,DE ; SUBTRACT FROM HL
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JR C,VRC_XY2IDX1 ; BYPASS IF NO WRAP
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POP DE ; THROW AWAY TOS
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RET ; DONE
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VRC_XY2IDX1:
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POP HL ; NO WRAP, RESTORE
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RET ; RETURN
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;
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;----------------------------------------------------------------------
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; SHOW OR HIDE CURSOR
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;----------------------------------------------------------------------
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;
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; VGARC USES HIGH BIT OF CHAR VALUE FOR INVERSE VIDEO. WE HAVE NO
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; HARDWARE CURSOR, SO WE LEVERAGE THE INVERSE VIDEO TO SHOW A CURSOR.
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; SINCE ANY OPERATION THAT POTENTIALLY OVERWERITES THE CURSOR POSITION
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; COULD DESTROY THE CURSOR, WE HAVE A COUPLE FUNCTIONS TO SHOW AND
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; HIDE THE CURSOR. A VARIABLE IS USED TO TRACK THE SHOW/HIDE
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; OPERATIONS BECAUSE WE MAY HAVE NESTED CALLS. ZERO MEANS SHOW
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; REAL CURSOR. ANY VALUE LESS THAN ZERO MEANS HIDDEN.
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;
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VRC_SHOWCUR:
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LD A,(VRC_CURSOR) ; GET CURRENT NESTING VALUE
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INC A ; INCREMENT TO SHOW
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LD (VRC_CURSOR),A ; SAVE IT
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RET NZ ; ALREADY SHOWN, NOTHING TO DO
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;
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; WE TRANSITIONED FROM NON-ZERO TO ZERO. NEED TO ACTUALLY
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; SHOW THE CURSOR NOW.
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;
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JR VRC_FLIPCUR
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;
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VRC_HIDECUR:
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LD A,(VRC_CURSOR) ; GET CURRENT NESTING VALUE
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DEC A ; DECREMENT TO HIDE
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LD (VRC_CURSOR),A ; SAVE IT
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INC A ; BACK TO ORIGINAL VALUE
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RET NZ ; ALREADY HIDDEN, NOTHING TO DO
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;
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; WE TRANSITIONED FROM ZERO TO NEGATIVE. NEED TO ACTUALLY
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; HIDE THE CURSOR NOW. SINCE SHOWING AND HIDING ARE THE
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; SAME OPERATION (FLIP REV VID BIT), WE REUSE CODE ABOVE.
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;
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JR VRC_FLIPCUR
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;
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VRC_FLIPCUR:
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; SHOWING OR HIDING THE CURSOR IS THE SAME OPERATION.
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; SO WE USE COMMON CODE TO FLIP THE REV VID BIT.
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LD HL,(VRC_POS) ; CURSOR POSITION
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LD B,L ; INVERT FOR I/O
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LD C,H
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IN A,(C) ; GET VALUE
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XOR $80 ; FLIP REV VID BIT
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OUT (C),A ; WRITE NEW VALUE
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RET
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;
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;----------------------------------------------------------------------
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; WRITE VALUE IN A TO CURRENT VDU BUFFER POSITION, ADVANCE CURSOR
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;----------------------------------------------------------------------
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;
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VRC_PUTCHAR:
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; WRITE CHAR AT CURRENT CURSOR POSITION. SINCE THE CURSOR
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; IS JUST THE HIGH BIT (REV VIDEO), WE FIRST TURN OFF THE
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; CURSOR, WRITE THE CHAR, UPDATE THE CURSOR POSITION, AND
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; FINALLY TURN THE CURSOR BACK ON AT THE NEW POSITION.
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;
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PUSH AF ; SAVE INCOMING CHAR
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CALL VRC_HIDECUR ; HIDE CURSOR
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POP AF
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LD HL,(VRC_POS) ; GET CUR BUF POSITION
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LD B,L ; INVERT FOR I/O
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LD C,H
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AND $7F ; SUPPRESS ATTRIBUTE (HI BIT)
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LD L,A ; PUT VALUE IN L
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LD A,(VRC_ATTR) ; GET CURRENT ATTRIBUTE
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OR L ; COMBINE WITH CHAR VALUE
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OUT (C),A ; WRITE VALUE TO BUFFER
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;
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; SET CURSOR AT NEW POSITION
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LD HL,(VRC_POS) ; GET CURRENT BUF OFFSET
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INC HL ; INCREMENT
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PUSH HL ; SAVE IT
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LD DE,VRC_ROWS * VRC_COLS ; DE := BUF SIZE
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OR A ; CLEAR CARRY
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SBC HL,DE ; SUBTRACT FROM HL
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JR C,VRC_PUTCHAR1 ; BYPASS IF NO WRAP
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POP DE ; THROW AWAY TOS
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LD HL,0 ; BACK TO START
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JR VRC_PUTCHAR2 ; CONTINUE
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VRC_PUTCHAR1:
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POP HL ; NO WRAP, RESTORE
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VRC_PUTCHAR2:
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LD (VRC_POS),HL ; SAVE NEW POSITION
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JP VRC_SHOWCUR ; SHOW IT AND RETURN
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;
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;----------------------------------------------------------------------
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; FILL AREA IN BUFFER WITH SPECIFIED CHARACTER AND CURRENT COLOR/ATTRIBUTE
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; STARTING AT THE CURRENT FRAME BUFFER POSITION
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; A: FILL CHARACTER
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; DE: NUMBER OF CHARACTERS TO FILL
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;----------------------------------------------------------------------
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;
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VRC_FILL:
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LD (VRC_FILL1+1),A ; SAVE FILL CHAR
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PUSH DE ; SAVE INCOMING DE
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CALL VRC_HIDECUR ; HIDE CURSOR
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POP DE ; RESTORE INCOMING DE
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LD HL,(VRC_POS) ; STARTING POSITION
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;
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VRC_FILL1:
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LD A,$FF ; FILL CHAR
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LD B,L ; INVERT FOR I/O
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LD C,H
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OUT (C),A ; PUT CHAR TO BUF
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;
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DEC DE ; DECREMENT COUNT
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LD A,D ; TEST FOR ZERO
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OR E
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JP Z,VRC_SHOWCUR ; EXIT VIA SHOW CURSOR IF DONE
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;
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INC HL ; INCREMENT
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PUSH HL ; SAVE IT
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LD BC,VRC_ROWS * VRC_COLS ; BC := BUF SIZE
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OR A ; CLEAR CARRY
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SBC HL,BC ; SUBTRACT FROM HL
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JR C,VRC_FILL2 ; BYPASS IF NO WRAP
|
|
POP BC ; THROW AWAY TOS
|
|
LD HL,0 ; BACK TO START
|
|
JR VRC_FILL3 ; CONTINUE
|
|
VRC_FILL2:
|
|
POP HL ; NO WRAP, RESTORE
|
|
VRC_FILL3:
|
|
LD (VRC_POS),HL ; SAVE NEW POSITION
|
|
JR VRC_FILL1 ; LOOP TILL DONE
|
|
;
|
|
;----------------------------------------------------------------------
|
|
; SCROLL ENTIRE SCREEN FORWARD BY ONE LINE (CURSOR POSITION UNCHANGED)
|
|
;----------------------------------------------------------------------
|
|
;
|
|
VRC_SCROLL:
|
|
; SCROLL DOWN 1 LINE VIA HARDWARE
|
|
CALL VRC_HIDECUR ; SUPPRESS CURSOR
|
|
LD A,(VRC_LOFF) ; GET LINE OFFSET
|
|
INC A ; BUMP
|
|
CP VRC_ROWS ; OVERFLOW?
|
|
JR C,VRC_SCROLL1 ; IF NOT, SKIP
|
|
XOR A ; ELSE, BACK TO ZERO
|
|
VRC_SCROLL1:
|
|
LD (VRC_LOFF),A ; SAVE NEW VALUE
|
|
OR $80 ; SET HW SCROLL ENABLE BIT
|
|
OUT (VRC_SCROLLIO),A ; DO IT
|
|
;
|
|
; ADJUST BUFFER OFFSET
|
|
LD HL,(VRC_OFF) ; BUFFER OFFSET
|
|
LD DE,VRC_COLS ; COLUMNS
|
|
ADD HL,DE ; ADD TO GET NEW OFFSET
|
|
PUSH HL ; SAVE IT
|
|
LD DE,VRC_ROWS * VRC_COLS ; DE := BUF SIZE
|
|
OR A ; CLEAR CARRY
|
|
SBC HL,DE ; SUBTRACT FROM HL
|
|
JR C,VRC_SCROLL2 ; BYPASS IF NO WRAP
|
|
POP DE ; BURN TOS
|
|
JR VRC_SCROLL3 ; CONTINUE
|
|
VRC_SCROLL2:
|
|
POP HL ; NO WRAP, RESTORE HL
|
|
VRC_SCROLL3:
|
|
LD (VRC_OFF),HL ; SAVE NEW OFFSET
|
|
;
|
|
; FILL EXPOSED LINE
|
|
LD HL,(VRC_POS) ; GET CURSOR POS
|
|
PUSH HL ; SAVE IT
|
|
LD D,VRC_ROWS - 1 ; LAST ROW
|
|
LD E,0 ; FIRST COLUMN
|
|
CALL VRC_XY2IDX ; HL = START OF LAST LINE
|
|
LD (VRC_POS),HL ; SET FILL POSITION
|
|
LD A,' ' ; FILL WITH BLANKS
|
|
LD DE,VRC_COLS ; FILL ONE LINE
|
|
CALL VRC_FILL ; FILL LAST LINE
|
|
POP HL ; RECOVER CURSOR POS
|
|
LD (VRC_POS),HL ; PUT VALUE BACK
|
|
;
|
|
; ADJUST CURSOR POSITION
|
|
LD HL,(VRC_POS) ; CURSOR POSITION
|
|
LD DE,VRC_COLS ; COLUMNS
|
|
ADD HL,DE ; NEW CURSOR POS
|
|
PUSH HL ; SAVE IT
|
|
LD DE,VRC_ROWS * VRC_COLS ; DE := DISPLAY SIZE
|
|
OR A ; CLEAR CARRY
|
|
SBC HL,DE ; SUBTRACT FROM HL
|
|
JR C,VRC_SCROLL4 ; BYPASS IF NO WRAP
|
|
POP DE ; BURN TOS
|
|
JR VRC_SCROLL5 ; CONTINUE
|
|
VRC_SCROLL4:
|
|
POP HL ; NO WRAP, RESTORE HL
|
|
VRC_SCROLL5:
|
|
LD (VRC_POS),HL ; SAVE NEW CURSOR POS
|
|
JP VRC_SHOWCUR ; EXIT VIA SHOW CURSOR
|
|
;
|
|
;----------------------------------------------------------------------
|
|
; REVERSE SCROLL ENTIRE SCREEN BY ONE LINE (CURSOR POSITION UNCHANGED)
|
|
;----------------------------------------------------------------------
|
|
;
|
|
VRC_RSCROLL:
|
|
; SCROLL UP 1 LINE VIA HARDWARE
|
|
CALL VRC_HIDECUR ; SUPPRESS CURSOR
|
|
LD A,(VRC_LOFF) ; GET LINE OFFSET
|
|
DEC A ; BUMP
|
|
CP $FF ; OVERFLOW?
|
|
JR NZ,VRC_RSCROLL1 ; IF NOT, SKIP
|
|
LD A,VRC_ROWS - 1 ; ELSE, BACK TO LAST ROW
|
|
VRC_RSCROLL1:
|
|
LD (VRC_LOFF),A ; SAVE NEW VALUE
|
|
OR $80 ; SET HW SCROLL ENABLE BIT
|
|
OUT (VRC_SCROLLIO),A ; DO IT
|
|
;
|
|
; ADJUST BUFFER OFFSET
|
|
LD HL,(VRC_OFF) ; BUFFER OFFSET
|
|
LD DE,VRC_COLS ; COLUMNS
|
|
OR A ; CLEAR CARRY
|
|
SBC HL,DE ; SUBTRACT TO GET NEW OFFSET
|
|
PUSH HL ; SAVE IT
|
|
JR NC,VRC_RSCROLL2 ; BYPASS IF NO WRAP
|
|
LD DE,VRC_ROWS * VRC_COLS ; DISPLAY SIZE
|
|
ADD HL,DE ; HANDLE WRAP
|
|
POP DE ; BURN TOS
|
|
JR VRC_RSCROLL3 ; CONTINUE
|
|
VRC_RSCROLL2:
|
|
POP HL ; NO WRAP, RESTORE HL
|
|
VRC_RSCROLL3:
|
|
LD (VRC_OFF),HL ; SAVE NEW OFFSET
|
|
;
|
|
; FILL EXPOSED LINE
|
|
LD HL,(VRC_POS) ; GET CURSOR POS
|
|
PUSH HL ; SAVE IT
|
|
LD D,0 ; FIRST ROW
|
|
LD E,0 ; FIRST COLUMN
|
|
CALL VRC_XY2IDX ; HL = START OF FIRST LINE
|
|
LD (VRC_POS),HL ; SET FILL POSITION
|
|
LD A,' ' ; FILL WITH BLANKS
|
|
LD DE,VRC_COLS ; FILL ONE LINE
|
|
CALL VRC_FILL ; FILL FIRST LINE
|
|
POP HL ; RECOVER CURSOR POS
|
|
LD (VRC_POS),HL ; PUT VALUE BACK
|
|
;
|
|
; ADJUST CURSOR POSITION
|
|
LD HL,(VRC_POS) ; CURSOR POSITION
|
|
LD DE,VRC_COLS ; COLUMNS
|
|
OR A ; CLEAR CARRY
|
|
SBC HL,DE ; NEW CURSOR POS
|
|
PUSH HL ; SAVE IT
|
|
JR NC,VRC_RSCROLL4 ; BYPASS IF NO WRAP
|
|
LD DE,VRC_ROWS * VRC_COLS ; DISPLAY SIZE
|
|
ADD HL,DE ; HANDLE WRAP
|
|
POP DE ; BURN TOS
|
|
JR VRC_RSCROLL5 ; CONTINUE
|
|
VRC_RSCROLL4:
|
|
POP HL ; NO WRAP, RESTORE HL
|
|
VRC_RSCROLL5:
|
|
LD (VRC_POS),HL ; SAVE NEW CURSOR POS
|
|
JP VRC_SHOWCUR ; EXIT VIA SHOW CURSOR
|
|
;
|
|
;----------------------------------------------------------------------
|
|
; BLOCK COPY BC BYTES FROM HL TO DE
|
|
;----------------------------------------------------------------------
|
|
;
|
|
VRC_BLKCPY:
|
|
PUSH BC
|
|
PUSH HL
|
|
CALL VRC_HIDECUR
|
|
POP HL
|
|
POP BC
|
|
;
|
|
VRC_BLKCPY1:
|
|
LD A,B
|
|
OR C
|
|
JP Z,VRC_SHOWCUR ; EXIT VIA SHOW CURSOR
|
|
;
|
|
PUSH BC ; SAVE LOOP CTL
|
|
LD B,L ; INVERT FOR I/O
|
|
LD C,H
|
|
IN A,(C) ; GET SOURCE CHAR
|
|
LD B,E ; INVERT FOR I/O
|
|
LD C,D
|
|
OUT (C),A ; WRITE DEST CHAR
|
|
POP BC ; RESTORE LOOP CTL
|
|
;
|
|
INC HL ; NEXT SRC CHAR
|
|
INC DE ; NEXT DEST CHAR
|
|
DEC BC ; DEC COUNT
|
|
JR VRC_BLKCPY1 ; LOOP TILL DONE
|
|
;
|
|
;==================================================================================================
|
|
; VGARC DRIVER - DATA
|
|
;==================================================================================================
|
|
;
|
|
VRC_ATTR .DB 0 ; CURRENT COLOR
|
|
VRC_POS .DW 0 ; CURRENT DISPLAY POSITION
|
|
VRC_OFF .DW 0 ; SCREEN START OFFSET INTO DISP BUF
|
|
VRC_LOFF .DB 0 ; LINE OFFSET INTO DISP BUF
|
|
VRC_CURSOR .DB 0 ; CURSOR NESTING LEVEL
|
|
VRC_ACTIVE .DB FALSE ; FLAG FOR DRIVER ACTIVE
|
|
;
|
|
;==================================================================================================
|
|
; VGA DRIVER - INSTANCE DATA
|
|
;==================================================================================================
|
|
;
|
|
VRC_IDAT:
|
|
.DB KBDMODE_VRC ; VGARC KEYBOARD CONTROLLER
|
|
.DB VRC_KBDST
|
|
.DB VRC_KBDDATA
|