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C02/x16/include/vera-old.a02
2019-09-25 23:16:28 -04:00

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; C02 module vera.h02 assembly language subroutines
; Requires External Functions NYBCAT, NYBCUT
; and Variables TEMP0
;getadr() - Get Vera Address
;Args: A = Bank + Auto-Increment
; Y,X = Address
GETADR: LDX $9F20 ;Store Address LSB
LDY $9F21 ;Store Address MSB
LDA $9F22 ;Store Bank & Auto-Increment
RTS
;getvid() - Get Video Output Mode
;Returns: A = Video Mode
; Y = Chroma Disabled
; X = Current Field
GETVID: LDA #$00 ;Set Register Offset to Video Output
JSR GETDCR ;Read from Display Composer
LDY #$00 ;Set Chroma Disabled to FALSE
LDX #$00 ;Set Video Field to EVEN
BIT GETVIM ;Test Chroma Disabled Bit
BEQ GETVIE ;If Bit 3 is Set
DEY ; Set Chroma Disabled to TRUE
BIT GETVIM ;Test Chroma Disabled Bit
GETVIE: BCC GETVIF ;If Bit 7 is Set
DEX ; Set Video Field to ODD
GETVIF: AND #$03 ;Isolate Bits 0-2 (Video Output Mode)
RTS
GETVIM: .DC $04 ;Chroma Disable Bit Mask
;getbdr() - Get Get Border Color
;Returns: A = Border Color Palette Index
GETBDR: LDA #$03 ;Set Register Offset to Border Color
;getdcr() - Get Display Composer Register
;Args: A = Register Offset
;Affects: Y
;Returns: A = Contents of Register
; X = Current Data Port
GETDCR: LDY #$00 ;Set MSB to Display Composer Page
TAX ;Set LSB to Register Offset
;and Execute GETREG
;getreg(&addr);
;Args: Y,X = Address
;Returns: A = Mode
; X = Current Data Port
GETREG: LDA #$0F ;Set Bank to Registers
GETBYT: JSR SETADR ;Set Vera Address
LDX $9F25 ;Get Current Data Port
LDA $9F23,X ;Read LSB from Data Port
RTS
;getmem(count, &addr) - Read Array From Vera Memory
;Args: A = Number of Bytes to Read
; Y,X = Address of Array to Read Into
;Requires: setadr()
;Sets: DSTLO,DSTHI = Address of Array
; TEMP0 = Number of Bytes to Read
;Affects: A
;Returns: Y = Number of Bytes Read
; X = Current Data Port
GETMEM: JSR SETDST ;Save Destination Address
GETMEA: STA TEMP0 ;Save Number of Bytes
LDY #0 ;Initialize Counter
LDX $9F25 ;Get Current Data Port
GETMEL: LDA $9F23,X ;Read Byte from Data Port
STA (DSTLO),Y ;Store in Memory
INY ;Increment Counter
CPY TEMP0 ;If Limit Not Reached
BNE GETMEL ; Loop
;getmod() - Get Layer 0/1 Mode
;Args: A = Layer (0/1)
;Affects: Y
;Returns: A = Layer Mode
; X = Current Data Port
GETMOD: JSR GETLRC ;Read Register
LSR ;Shift Left Five Bits
LSR
LSR
LSR
RTS
;getenb() - Get Layer 0/1 Enabled
;Args: A = Layer (0/1)
;Affects: Y
;Returns: A = $FF - Layer Enabled
; $00 - Layer Disabled
; X = Current Data Port
GETENB: JSR GETLRC ;Read Register
AND #$01 ;Isolate Bit 1
BEQ GETENX ;If Set
LDA #$FF ; Return TRUE
GETENX: RTS ;Else Return FALSE
;getlrc() - Get Layer 0/1 Control Register
;Args: A = Layer (0/1)
;Affects: Y
;Returns: A = Control Register Contents
; X = Current Data Port
GETLRC: LDX #0 ;Set Offset to Control Register
;getlrr() - Get Layer 0/1 Register
;Args: A = Layer (0/1)
; X = Register Offset
;Affects: Y
;Returns: A = Contents of Register
; X = Current Data Port
GETLRR: JSR GETLRP ;Get Layer Page in Y
BNE GETREG ;and Read Register Contents
;getlrp() - Get Layer 0/1 Register Page
;Args: A = Layer (0/1)
;Returns: A,Y = Layer Register Page
GETLRP: AND #$01 ;Isolate Bit 1
ASL ;Move to Left Nybble
ASL
ASL
ASL
ORA #$20 ;And Add to 2
TAY ;Return Page in Y
RTS
;getchd(index, &array) - Read Character Data into Array
;Args: A = Character Index
; Y,X = Address of Array to Read into
;Destroys: TEMP0,TEMP1,TEMP2
;Returns: A = Number of Bytes Read
GETCHD: JSR SETDST ;Store Address in Destination Pointer
STA TEMP1 ;Set Offset LSB to Index
LDA #0 ;Set Offset MSB to Zero
ASL TEMP1 ;Multiple Offset by 2
ROL
STA TEMP2 ;and Store MSB
JSR GETLRI ;Get Tile Base
TXA ;Add Offset To Tile Base
CLC
ADC TEMP0
STA TEMP0
TYA
ADC TEMP1
STA TEMP1
LDA #0
ADC #0
JSR GETMBX ;Multiply by 4
ORA #$10 ;Set Auto-Increment to 1
JSR SETADR ;and Set Vera Address
LDA #8 ;Set Byte Count to 8
BNE GETMEA ;and Read Bytes into Array
;gettba() - Get Layer 0/1 Tile Base Address
;Args: A = Layer (0/1)
;Destroys: TEMP1,TEMP2
;Returns: A = Tile Base Bank
; Y,X = Tile Base Address
GETTBA: LDX #4 ;Set Register Offset
.DC $2C ;Read Register Pair and Rotate
;getmba() - Get Layer 0/1 Map Base Address
;Args: A = Layer (0/1)
;Destroys: TEMP1,TEMP2
;Returns: A = Map Base Bank
; Y,X = Map Base Address
GETMBA: LDX #2 ;Set Register Offset
JSR GETLRI ;Read Register Pair as Integer
LDA #0 ;Initialize Page to 0
JSR SAVRXY ;Save Integer in TEMP1,TEMP2
GETMBX: LDX #2 ;Do Twice
GETMBL: ASL TEMP1 ; Rotate LSB
ROL TEMP2 ; MSB and
ROL ; Bank Left
DEX
BNE GETMBL
JMP RESRXY ;Load LSB, MSB and Return
;getvsc() - Get Layer 0/1 Vertical Scroll
;Args: A = Layer (0/1)
;Returns: A,X = Vertical Scroll LSB
; Y = Vertical Scroll MSB
GETVSC: LDX #8 ;Set Register Offset
.DC $2C ;Skip to GETLRI (BIT Absolute)
;gethsc() - Get Layer 0/1 Horizontal Scroll
;Args: A = Layer (0/1)
;Returns: A,X = Horizontal Scroll LSB
; Y = Horizontal Scroll MSB
GETHSC: LDX #6 ;Set Register Offset
.DC $2C ;Skip to GETLRI (BIT Absolute)
;gettbs() - Get Layer 0/1 Tile Base
;Args: A = Layer (0/1)
;Returns: A,X = Tile Base LSB
; Y = Tile Base MSB
GETTBS: LDX #4 ;Set Register Offset
.DC $2C ;Skip to GETLRI (BIT Absolute)
;getmbs() - Get Layer 0/1 Map Base
;Args: A = Layer (0/1)
;Returns: A,X = Map Base LSB
; Y = Map Base MSB
GETMBS: LDX #2 ;Set Register Offset
;getlri() - Get Layer 0/1 Register Pair as Integer
;Args: A = Layer (0/1)
; X = Register Offset
;Returns: A,X = Integer LSB
; Y = Integer LSB
GETLRI: JSR GETLRP ;Get Layer Page in Y
BNE GETREI ;and Read Register Contents
;mapsiz() - Convert Map Size Specifier to Pixels
;Args: A = Map Size Specifier
;Affects: A
;Returns: Y,X Map Size in Pixels
MAPSIZ: TAX ;Copy Map Size Specifier to X
LDA MAPSIH,X ;Load Pixels MSB from Table
TAY ;and Return in Y
LDA MAPSIL,X ;Load Pixels LSB from Table
TAX ;and Return in X
MAPSIL: .DC $20,$40,$80,$00
MAPSIH: .DC $00,$00,$00,$01
;tilsiz() - Convert Tile Size Specifier to Pixels
;Args: A = Tile Size Specifier
;Affects: A
;Returns: A Tile Size in Pixels
TILSIZ: TAX ;Copy Map Size Specifier to X
LDA TILSIT,X ;Load Pixels MSB from Table
RTS
TILSIT: .DC $08,$10
;gettsz() - Get Layer 0/1 Tile Size
;getmsz() - Get Layer 0/1 Map Size
;Args: A = Layer (0/1)
;Affects: X
;Returns: A = Map Width Specifier
; Y = Map Height Specifier
;getvsp() - Get Vertical Stop
;Affects: A
;Returns: Y,X = Vertical Stop
GETVSP: LDA #7 ;Set Reg Offset to Vertical Stop
JSR GETHVS ;Read Registers
LSR ;Shift Left One Bit
JMP GETVSS ;Then Four More Bits and Mask
;getvsr() - Get Vertical Start
;Affects: A
;Returns: Y,X = Vertical Start
GETVSR: LDA #6 ;Set Reg Offset to Vertical Start
JSR GETHVS ;Read Registers
GETVSS: LSR ;Shift Left Four Bit
LSR
LSR
LSR
AND #$01 ;Isolate Bit 0
TAY ;and Copy MSB to Y
RTS
;gethsp() - Get Horizontal Stop
;Affects: A
;Returns: Y,X = Horizontal Stop
GETHSP: LDA #5 ;Set Lookup Index to Horizontal Start
JSR GETHVS ;Read Registers
LSR ;Shift Left Two Bits
LSR
JMP GETHSS ;then Mask and Return
;gethsr() - Get Horizontal Start
;Affects: A
;Returns: Y,X = Horizontal Start
GETHSR: LDA #4 ;Set Lookup Index to Horizontal Start
JSR GETHVS ;Read Registers
;.dc $ff ;debug
GETHSS: AND #$03 ;Isolate Bit 0
TAY ;and Copy MSB to Y
RTS
;gethvs() - Get Start/Stop Low Byte and High Bits
;Args: X = Low Register
;Affects: Y
;Returns: A = High Bits
; X = Low Byte
GETHVS: JSR GETDCR ;Read LSB from Register
;.dc $ff ;debug
PHA ;and Save It
LDA #8 ;Load Register Offset for High Bits
STA $9F20 ;Set As Address LSB
LDA $9F23,X ;and Read High Bits into A
.DC $FA ;PLX ;Restore LSB into X
RTS
;getiql() - Get Interrupt Line
;Affects: A
;Returns: Y,X = Interrupt Line#
GETIQL: LDA #9 ;Set Register Offset to Interrupt Line
.DC $2C ;Skip to SETDCX (BIT Absolute)
;getscl() - Get Horizontal and Vertical Scale
;Returns: A,X = Horizontal Scale
; Y = Vertical Scale
GETSCL: LDA #1 ;Set Register Offset to HSCALE,VSCALE
.DC $2C ;Skip SETDCI (BIT Absolute)
;getdci() - Get Display Composer Register Pair
;Args: A = Register Offset
;Affects: Y
;Returns: A,X = Integer LSB
; Y = Integer LSB
GETDCI: LDY #$00 ;Set MSB to Display Composer Page
TAX ;Set LSB to Register Offset
;and Execute GETREI
;getrei(addr); Read Vera Register Pair
;Args: Y,X = Address
;Returns: A,X = Integer LSB
; Y = Integer LSB
GETREI: LDA #$0F ;Set Bank to Registers
;getint(addr); Read Integer from Vera Memory
;Args: A = Bank
; Y,X = Address
;Returns: A,X = Integer LSB
; Y = Integer LSB
GETINT: ORA #$10 ;Set Auto-Increment to 1
JSR SETADR ;Set Vera Address
LDX $9F25 ;Get Current Data Port
LDA $9F23,X ;Read LSB from Data Port
LDY $9F23,X ;Read MSB Data Port
TAX ;Copy LSB to X
RTS
;setvsp() - Set Horizontal Stop
;Args: Y,X = Horizontal Stop
;Affects: A,X,Y
SETVSP: TYA ;Convert MSB to High Bit
AND #$01
ASL
ASL
ASL
ASL
ASL
STA TEMP1 ;and Save
TXA ;Copy LSB to Accumlator
LDX #7 ;Set Register Offset to Horizontal Start
LDY #$DF ;Set High Bits Mask
JMP SETHST ;OR in High Bits and Write Back
;setvsr() - Set Horizontal Start
;Args: Y,X = Horizontal Start
;Affects: A,X,Y
SETVSR: TYA ;Convert MSB to High Bit
AND #$01
ASL
ASL
ASL
ASL
STA TEMP1 ;and Save
TXA ;Copy LSB to Accumlator
LDX #6 ;Set Register Offset to Horizontal Start
LDY #$EF ;Set High Bits Mask
JMP SETHST ;OR in High Bits and Write Back
;sethsp() - Set Horizontal Stop
;Args: Y,X = Horizontal Stop
;Affects: A,X,Y
SETHSP: TYA ;Convert MSB to High Bits
AND #$03
ASL
ASL
STA TEMP1 ;and Save
TXA ;Copy LSB to Accumlator
LDX #5 ;Set Register Offset to Horizontal Start
LDY #$F3 ;Set High Bits Mask
JMP SETHST ;OR in High Bits and Write Back
;sethsr() - Set Horizontal St7art
;Args: Y,X = Horizontal Start
;Destroys TEMP0,TEMP1,TEMP2
;Affects: A,X,Y
SETHSR: TYA ;Convert MSB to High Bits
AND #$03
STA TEMP1 ;and Save
TXA ;Copy LSB to Accumlator
LDX #4 ;Set Register Offset to Horizontal Start
LDY #$FC ;Set High Bits Mask
SETHST: STY TEMP2 ;Save
JSR SETHVS ;Write LSB and Get High Bits
AND TEMP2 ;Mask Start Stop High
ORA TEMP1 ;OR in High Bits
STA $9F23,X ;and Write back to Register
RTS
SETHVS: JSR SETDCX ;Write LSB
LDA #8 ;Load Register Offset for High Bits
STA $9F20 ;Set As Address LSB
LDA $9F23,X ;and Read High Bits into A
RTS
;setvid() - Set Video Output Mode
;Args: A = Video Mode
; Y = Chroma Disabled
;Destroys: TEMP0
SETVID: AND #3 ;Isolate Video Mode Bits
CPY #0 ;Set Chroma Mask to
BEQ SETVIF ; 0 if Y is Zero or
LDY #4 ; 4 if it is not
SETVIF: STY TEMP0 ;Save Chroma Bit
ORA TEMP0 ;Combine with Video Mode Bits
LDX #0 ;Set Register Offset to Video Mode
BEQ SETDCX ;Write to Register
;setbdr() - Set Border Color
;Args: A = Border Color Palette Index
SETBDR: LDX #3 ;Set Register Offset to Border Color
.DC $2C ;Skip to SETDCX (BIT Absolute)
;setdcr() - Set Display Composer Register
;Args: A = Register Offset
; Y = Value to Write
;Affects: Y
;Returns: A = Value Written
; X = Current Data Port
SETDCR: TAX ;Set LSB to Register Offset
TYA ;Move Write Value to Accumulator
SETDCX: LDY #$00 ;Set MSB to Display Composer Page
;setreg(addr) - Set Register
;Args: A = Value to Write
; Y,X = Address
;Sets: TEMP0 = Value to Write
;Affects: Y
;Returns: A = Value Written
; X = Current Data Port
SETREG: STA TEMP0 ;Save Value to Write
SETREH: LDA #$0F ;Set Bank, Auto-Increment
;setbyt(addr) - Write Byte to Vera Memory
;Args: A = Bank
; Y,X = Address
;Uses: TEMP0 = Value to Write
;Affects: Y
;Returns: A = Value Written
; X = Current Data Port
SETBYT: JSR SETADR ;Set Vera Address
LDA TEMP0 ;Retrieve Value to Write
LDX $9F25 ;Get Current Data Port
STA $9F23,X ;Write Value to Data Port
RTS
;settbs() - Set Layer 0/1 Map Base
;Args: A = Layer (0/1)
; Y,X = Map Base
;Sets: TEMP1,TEMP2 = Map Base
;Affecta: A,Y,X
SETTBS: JSR SAVRXY ;Store Map Base in TEMP1,TEMP2
LDX #4 ;Set Register Offset
BNE SETLRI ;Write to Layer Register
;setmbs() - Set Layer 0/1 Map Base
;Args: A = Layer (0/1)
; Y,X = Map Base
;Sets: TEMP1,TEMP2 = Map Base
;Affecta: A,Y,X
SETMBS: JSR SAVRXY ;Store Map Base in TEMP1,TEMP2
LDX #2 ;Set Register Offset
BNE SETLRI ;Write to Layer Register
;setvsc() - Set Layer 0/1 Vertical Scroll
;Args: A = Layer (0/1)
; Y,X = Map Base
;Sets: TEMP1,TEMP2 = Vertical Scroll
;Affecta: A,Y,X
SETVSC: JSR SAVRXY ;Store Vertical Scroll in TEMP1,TEMP2
LDX #8 ;Set Register Offset
BNE SETLRI ;Write to Layer Register
;sethsc() - Set Layer 0/1 Horizontal Scroll
;Args: A = Layer (0/1)
; Y,X = Map Base
;Sets: TEMP1,TEMP2 = Horizontal Scroll
;Affecta: A,Y,X
SETHSC: JSR SAVRXY ;Store Horizontal Scroll in TEMP1,TEMP2
LDX #6 ;Set Register Offset
;setlri() - Write Integer to Get Layer 0/1 Register
;Args: A = Layer (0/1)
; X = Register Offset
;Uses: TEMP1,TEMP2 = Integer Value
;Affecta: A,Y,X
SETLRI: JSR GETLRP ;Get Layer Page in Y
BNE SETREI ;and Write Integer to Register
;setiql() - Set IRQ Line
;Args: Y,X = IRQ Line Number`
;Sets: TEMP1,TEMP2 = IRQ Line Number
;Affecta: A,Y,X
SETIQL: TXA ;Copy LSB to Accumulator
LDX #9 ;Set Register Offset to HSCALE,VSCALE
.DC $2C ;Skip to SETDCP (BIT Absolute)
;setscl() - Set Horizontal and Vertical Scale
;Args: A = Horizontal Scale
; Y = Vertical Scale
SETSCL: LDX #1 ;Set Register Offset to HSCALE,VSCALE
;setdcp() - Set Display Composer Register Pair
;Args: A = First Register Value
; Y = Second Register Value
; X = Register Offset
;Affects: A,Y
;Returns: X = Current Data Port
SETDCP: STA TEMP1 ;Store First Value as LSB
STY TEMP2 ;Store Second Value as MSB
LDY #$00 ;Set MSB to Display Composer Page
;setrei(addr); Set Vera Register to Integer
;Args: Y,X = Address
;Uses: TEMP1,TEMP2 = Integer Value
;Affects: A,Y
;Returns: X = Current Data Port
SETREI: LDA #$0F ;Set Bank to Registers
;setint(addr); Write Integer to Vera Memory
;Args: A = Bank
; Y,X = Address
;Uses: TEMP1,TEMP2 = Integer Value
;Affects: A,Y
;Returns: X = Current Data Port
SETINT: ORA #$10 ;Set Auto-Increment to 1
JSR SETADR ;Set Vera Address
LDX $9F25 ;Get Current Data Port
LDA TEMP1 ;Get LSB
STA $9F23,X ;Write to Data Port
LDA TEMP2 ;Get MSB
STA $9F23,X ;Write to Data Port
RTS
;setmem(count, &addr) - Write Array to Vera Memory
;Args: A = Number of Bytes to Write
; Y,X = Address of Array to Write From
;Requires: setadr()
;Sets: SRCLO,SRCHI = Address of Array
; TEMP0 = Number of Bytes to Write
;Affects: A
;Returns: Y = Number of Bytes Written
; X = Current Data Port
SETMEM: STA TEMP0 ;Save Number of Bytes
JSR SETSRC ;Save Destination Address
LDX $9F25 ;Get Current Data Port
LDY #0 ;Initialize Counter
SETMEL: LDA (SRCLO),Y ;Read Byte from Array
STA $9F23,X ;Write Byte to Data Port
INY ;Increment Counter
CPY TEMP0 ;If Limit Not Reached
BNE SETMEL ; Loop
RTS
;rgbclr(r,g,b) - Convert RGB Values to Palette Color
;Args: A = Red Value (0-15)
; Y = Green Value (0-15)
; X = Blue Value (0-15)
;Affects: A
;Returns: Y = Color MSB (0000RRRR)
; X = Color LSB (GGGGBBBB)
RGBCLR: PHA ;Save Red Value
TYA ;Copy Green Value to Left Nybble
.DC $DA ;PHX Copy Blue Value
.DC $7A ;PLY to Right Nybble
JSR NYBCAT ;Concatanate Green and Blue
TAX ;and Return as LSB
.DC $7A ;PLY Return Red as MSB
RTS
;clrrgb(c) - Convert Palette Color to RGB Values
;Args: Y = Color MSB (0000RRRR)
; X = Color LSB (GGGGBBBB)
;Returns: A = Red Value (0-15)
; Y = Green Value (0-15)
; X = Blue Value (0-15)
CLRRGB: .DC $5A ;PHY Save MSB
TXA ;Copy LSB into Accumulator
JSR NYBCUT ;and Split into Nybbles
.DC $5A ;PHY Return Blue Value
.DC $FA ;PLX in X Register
TAY ;Green Value in Y Register
PLA ;and Red Value in Accumulator
RTS
;getclr(idx) - Get Color Entry idx from Palette
;Args: A = Color Entry Index
;Affects: A
;Returns: Y = Color MSB (0000RRRR)
; X = Color LSB (GGGGBBBB)
GETCLR: JSR SETIDX ;Set Vera Address to Palette Index
LDX $9F25 ;Get Current Data Port
LDA $9F23,X ;Read LSB from Data Port
LDY $9F23,X ;Read MSB from Data Port
TAX ;Copy LSB to X Register
RTS
;setclr(idx) - Set Color Entry idx in Palette
;Args: A = Color Entry Index
; Y = Color MSB (0000RRRR)
; X = Color LSB (GGGGBBBB)
;Affects: A
;Returns: Y,X = Color Entry Address
SETCLR: JSR SAVRXY ;Save Color Value
JSR SETIDX ;Set Vera Address to Palette Index
LDX $9F25 ;Get Current Data Port
LDA TEMP1 ;Retrieve Color Value LSB
STA $9F23,X ;and Write to Data Port
LDA TEMP2 ;Retrieve Color Value MSB
STA $9F23,X ;Read MSB from Data Port
RTS
;setidx(idx) - Set Vera Address to Palette Index
;Args: A = Index
;Returns: A = Bank + Auto-Increment
; Y,X = Address
SETIDX: ASL ;Multiply Index by 2
TAX ;and Set as LSB
LDA #$10 ;Get Palette Page
ADC #$00 ;Add Carry from Multiply
TAY ;and Set as MSB
;regadr(opts,addr) - Set Vera Address to Internal Register
;Args: Y,X = Register Address
;Returns: A= Bank + Auto-Increment
REGADR: LDA #$1F ;Set Bank and Auto-Increment
;setadr(opts,addr) - Set Vera Address
;Args: A = Bank + Auto-Increment
; Y,X = Address
SETADR: STX $9F20 ;Store Address LSB
STY $9F21 ;Store Address MSB
STA $9F22 ;Store Bank & Auto-Increment
RTS