mirror of
https://github.com/RevCurtisP/C02.git
synced 2024-11-24 15:31:17 +00:00
385 lines
12 KiB
Plaintext
385 lines
12 KiB
Plaintext
; Vera Layer Control Assembly Language Routines for C02
|
|
; Requires External Routines GETVRG, GETVRI, RESRXY, SAVREG, SAVRXY
|
|
; and External Variables TEMP0, TEMP1, TEMP2, TEMP3
|
|
|
|
;Layer 0/1 Registers
|
|
;$F2000/$F3000 Layer Control (Mode and Enabled)
|
|
;$F2001/$F3001 Tile and Map Height and Width
|
|
;$F2002/$F3002 Map Base Bits 9-2
|
|
;$F2003/$F3003 Map Base Bits 17-10
|
|
;$F2004/$F3004 Tile Base Bits 9-2
|
|
;$F2005/$F3005 Tile Base Bits 17-10
|
|
;$F2006/$F3006 Horizontal Scroll LSB
|
|
;$F2007/$F3007 Horizontal Scroll MSB or Bitmap Palette Offset
|
|
;$F2008/$F3008 Vertical Scroll LSB
|
|
;$F2009/$F3009 Vertical Scroll MSB
|
|
|
|
;getbpo(lyr) - Get Bitmap Palette Offset
|
|
;Args: A = Layer (0/1)
|
|
;Affects: Y
|
|
;Sets: TEMP3 = Register Offset
|
|
;Returns: A = Control Register Contents
|
|
; X = Current Data Port
|
|
GETBPO: LDX #7 ;Set Offset to Bitmap Palette Offset
|
|
JSR GETLRR ;Read Register
|
|
ASL ;and Multiply by 16
|
|
ASL
|
|
ASL
|
|
ASL
|
|
RTS
|
|
|
|
;getlrs(lyr) - Get Layer 0/1 Size Register
|
|
;Args: A = Layer (0/1)
|
|
;Affects: Y
|
|
;Sets: TEMP3 = Register Offset
|
|
;Returns: A = Size Register Contents
|
|
; X = Current Data Port
|
|
GETLRS: LDX #1 ;Set Offset to Size Register
|
|
.DC $2C ;Skip to GETLRR (BIT Absolute)
|
|
|
|
;getlrc(lyr) - Get Layer 0/1 Control Register
|
|
;Args: A = Layer (0/1)
|
|
;Affects: Y
|
|
;Sets: TEMP3 = Register Offset
|
|
;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
|
|
;Sets: TEMP3 = Register Offset
|
|
;Affects: Y
|
|
;Returns: A = Contents of Register
|
|
; X = Current Data Port
|
|
GETLRR: STX TEMP3 ;Save Register Offset - Obselete?
|
|
JSR GETLRP ;Get Layer Page in Y
|
|
JMP GETVRG ;and Read Vera Register
|
|
|
|
;getlrp(lyr) - 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
|
|
|
|
;getenb(lyr) - 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
|
|
|
|
;getmod(lyr) - 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
|
|
LSR
|
|
RTS
|
|
|
|
;getmsz(lyr) - Get Layer 0/1 Map Size
|
|
;Args: A = Layer (0/1)
|
|
;Affects: X
|
|
;Returns: A = Width Specifier
|
|
; Y = Height Specifier
|
|
GETMSZ: JSR GETLRS ;Read Size Register
|
|
TAX ;Save Contents
|
|
LSR ;Shift Right 2 Bits
|
|
LSR
|
|
AND #$03 ;Isolate Bits 0 and 1
|
|
TAY ;and Return in Y
|
|
TXA ;Restore Register Contents
|
|
AND #$03 ;Return Bits 0 and 1 in A
|
|
RTS
|
|
|
|
;gettsz(lyr) - Get Layer 0/1 Map Size
|
|
;Args: A = Layer (0/1)
|
|
;Affects: X
|
|
;Returns: A = Width Specifier
|
|
; Y = Height Specifier
|
|
GETTSZ: JSR GETLRS ;Read Size Register
|
|
LSR ;Shift Right 4 Bits
|
|
LSR
|
|
LSR
|
|
LSR
|
|
TAX ;Save Intermediate Value
|
|
LSR ;Shift Right 1 More Bit
|
|
AND #$01 ;Isolate Bit 0
|
|
TAY ;and Return in Y
|
|
TXA ;Restore Intermediate Value
|
|
AND #$01 ;and Return Bit 0 in A
|
|
RTS
|
|
|
|
;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
|
|
JMP GETVRI ;and Read Register Contents
|
|
|
|
;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)
|
|
;Sets: TEMP0 = Bank
|
|
; TEMP1 = Address LSB
|
|
; TEMP2 = Address MSB
|
|
;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 SAVREG ;Save Integer in TEMP1,TEMP2
|
|
LDX #2 ;Set Count to 2
|
|
JMP ASLADR ;and Shift Address Left
|
|
|
|
;mapsiz() - Convert Map Size Specifier to Pixels
|
|
;Args: A = Map Size Specifier
|
|
;Affects: A
|
|
;Returns: A = Shift Count
|
|
; Y,X Map Size in Pixels
|
|
MAPSIZ: TAX ;Copy Size Specifier to X
|
|
LDA MAPSIC,X ;Load Shift Count from Table
|
|
PHA ;and Save it
|
|
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
|
|
PLA ;Return Shift Count in A
|
|
RTS
|
|
MAPSIC: .DC $05,$06,$07,$08
|
|
MAPSIL: .DC $20,$40,$80,$00
|
|
MAPSIH: .DC $00,$00,$00,$01
|
|
|
|
;tilsiz() - Convert Tile Size Specifier to Pixels
|
|
;Args: A = Tile Size Specifier
|
|
;Returns: A = Tile Size in Pixels
|
|
; Y = Shift Count
|
|
TILSIZ: TAX ;Copy Map Size Specifier to X
|
|
LDA TILSIT,X ;Return Pixels in A
|
|
LDY TILSIC,X ;and Shift Count in Y
|
|
RTS
|
|
TILSIC: .DC $03,$04
|
|
TILSIT: .DC $08,$10
|
|
|
|
;setbpo(lyr) - Set Bitmap Palette Offset
|
|
;Args: A = Layer (0/1)
|
|
; Y = Bitmap Palette Offset
|
|
;Affects: Y
|
|
;Sets: TEMP3 = Register Offset
|
|
;Returns: A = Control Register Contents
|
|
; X = Current Data Port
|
|
SETBPO: PHA ;Save Layer Number
|
|
TYA ;Copy Offset to Accumulator
|
|
LSR ;Divide by 16
|
|
LSR
|
|
LSR
|
|
LSR
|
|
TAY ;Copy Back to Y
|
|
PLA ;Restore Layer Number
|
|
LDX #7 ;Set Register Offset
|
|
BNE SETLRR ;and Write to Register
|
|
|
|
;setenb(lyr,flg) - Get Layer 0/1 Enabled
|
|
;Args: A = Layer (0/1)
|
|
; Y = Layer Enabled Flags
|
|
;Destroys: TEMP0
|
|
;Affects: A,X,Y
|
|
SETENB: CPY #0 ;Test Enabled Argument`
|
|
BEQ SETENZ ;If Not Zero
|
|
LDY #$01 ; Set to 1
|
|
SETENZ: LDX #$FE ;Set Control Register Mask
|
|
|
|
;setlrc(lyr,val,msk) - Set Layer 0/1 Control Register
|
|
;Args: A = Layer (0/1)
|
|
; Y = Value to Write
|
|
; X = Register Mask
|
|
;Affects: Y
|
|
;Returns: A = Value Written
|
|
; X = Current Data Port
|
|
SETLRC: JSR SAVREG ;Save Layer, Value, and Mask
|
|
JSR GETLRC ;Get Layer Control Register
|
|
SETLRM: AND TEMP1 ;Apply Mask
|
|
ORA TEMP2 ;OR in Value
|
|
TAY ;and Move to Y Register
|
|
LDA TEMP0 ;Restore Layer Number
|
|
LDX TEMP3 ;Get Register Offset
|
|
|
|
;setlrr() - Set Layer 0/1 Register
|
|
;Args: A = Layer (0/1)
|
|
; Y = Value to Write
|
|
; X = Register Offset
|
|
;Affects: Y
|
|
;Returns: A = Contents of Register
|
|
; X = Current Data Port
|
|
SETLRR: ;.dc $ff
|
|
PHY ;Save Value to Write
|
|
JSR GETLRP ;Get Layer Page in Y
|
|
PLA ;Restore Value to Write
|
|
JMP SETREG ;and Write to Register
|
|
|
|
;setlrs(lyr,val,msk) - Set Layer 0/1 Size Register
|
|
;Args: A = Layer (0/1)
|
|
/; Y = Value to Write
|
|
; X = Register Mask
|
|
;Affects: Y
|
|
;Returns: A = Value Written
|
|
; X = Current Data Port
|
|
SETLRS: ;.dc $ff
|
|
JSR SAVREG ;Save Layer, Value, and Mask
|
|
JSR GETLRS ;Get Layer Size Register
|
|
BRA SETLRM ;Mask in Value and Write Back
|
|
|
|
;setmod() - Set Layer 0/1 Mode
|
|
;Args: A = Layer (0/1)
|
|
; Y = Layer Mode
|
|
;Destroys: TEMP0
|
|
;Affects: A,X,Y
|
|
SETMOD: TAX ;Save Layer Number
|
|
TYA ;Copy Mode to Accumulator
|
|
ASL ;Shift to Bits 5-7
|
|
ASL
|
|
ASL
|
|
ASL
|
|
ASL
|
|
TAY ;Copy Write Value to Y
|
|
TXA ;Restore Layer Number
|
|
LDX #$1F ;Set Control Register Mask
|
|
BNE SETLRC ;and Update Control Register
|
|
|
|
;setmsz(lyr) - Set Layer 0/1 Map Size
|
|
;Args: A = Layer (0/1)
|
|
; Y = Width Specifier
|
|
; X = Height Specifier
|
|
;Destroys: TEMP0
|
|
;Affects: A,X,Y
|
|
SETMSZ: PHA ;Save Layer Number
|
|
TXA ;Get Height Specifier
|
|
AND #$03 ;Strip High Bits
|
|
ASL ;Rotate Left 2 Bits
|
|
ASL
|
|
STA TEMP0 ;and Save It
|
|
TYA ;Get Width Specifier
|
|
AND #$03 ;Strip High Bits
|
|
ORA TEMP0 ;OR in Height Specifier
|
|
TAY ;Copy Write Value to Y
|
|
PLA ;Restore Layer Number
|
|
LDX #$F0 ;Set Size Register Mask
|
|
BNE SETLRS ;and Update Size Register
|
|
|
|
;settsz(lyr) - Set Layer 0/1 Tile Size
|
|
;Args: A = Layer (0/1)
|
|
; Y = Width Specifier
|
|
; X = Height Specifier
|
|
;Destroys: TEMP0
|
|
;Affects: A,X,Y
|
|
SETTSZ: PHA ;Save Layer Number
|
|
TXA ;Get Height Specifier
|
|
AND #$01 ;Strip High Bits
|
|
ASL ;Rotate Left 1 Bits
|
|
STA TEMP0 ;and Save It
|
|
TYA ;Get Width Specifier
|
|
AND #$01 ;Strip High Bits
|
|
ORA TEMP0 ;OR in Height Specifier
|
|
ASL ;Shift Left 4 More Bits
|
|
ASL
|
|
ASL
|
|
ASL
|
|
TAY ;Copy Write Value to Y
|
|
PLA ;Restore Layer Number
|
|
LDX #$CF ;Set Size Register Mask
|
|
BNE SETLRS ;and Update Size Register
|
|
|
|
;sethsc() - Set Layer 0/1 Horizontal Scroll
|
|
;Args: A = Layer (0/1)
|
|
; Y,X = Map Base
|
|
;Sets: TEMP1,TEMP2 = Horizontal Scroll
|
|
;Affects: 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
|
|
;Affects: A,Y,X
|
|
SETLRI: JSR GETLRP ;Get Layer Page in Y
|
|
JMP SETREI ;and Write Integer to Register
|
|
|
|
;setmbs() - Set Layer 0/1 Map Base
|
|
;Args: A = Layer (0/1)
|
|
; Y,X = Map Base
|
|
;Sets: TEMP1,TEMP2 = Map Base
|
|
;Affects: A,Y,X
|
|
SETMBS: JSR SAVRXY ;Store Map Base in TEMP1,TEMP2
|
|
LDX #2 ;Set Register Offset
|
|
BNE SETLRI ;Write to Layer Register
|
|
|
|
;settbs() - Set Layer 0/1 Map Base
|
|
;Args: A = Layer (0/1)
|
|
; Y,X = Map Base
|
|
;Sets: TEMP1,TEMP2 = Map Base
|
|
;Affects: A,Y,X
|
|
SETTBS: JSR SAVRXY ;Store Map Base in TEMP1,TEMP2
|
|
LDX #4 ;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
|
|
;Affects: A,Y,X
|
|
SETVSC: JSR SAVRXY ;Store Vertical Scroll in TEMP1,TEMP2
|
|
LDX #8 ;Set Register Offset
|
|
BNE SETLRI ;Write to Layer Register
|