mirror of https://github.com/RevCurtisP/C02.git
Added Atari 2600 library and documentation files vcs/include/*
This commit is contained in:
Curtis F Kaylor
parent
05d8d9fbb0
commit
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;arena.a02 - Two Line Arena Kernal for Atari 2600
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;Requires Constants ARLINS, P0LINS and P1LINS
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P0DRAW EQU $D0 ;Player 0 Draw Counter
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P1DRAW EQU $D1 ;Player 1 Draw Counter
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P0PTRL EQU $D2 ;Player 0 Graphics Pointer
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P0PTRH EQU $D3
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P1PTRL EQU $D4 ;Player 0 Graphics Pointer
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P1PTRH EQU $D5
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P0OFST: STA TEMP0 ;Save Multiplier
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BEQ POFFSX ;If 0, Return
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LDA #P0LINS ;Load # of Lines
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BNE POFFST
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P1OFST: STA TEMP0 ;Save Multiplier
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BEQ POFFSX ;If 0, Return
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LDA #P1LINS ;Load # of Lines
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POFFST: STA TEMP1
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POFFSL: TXA
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CLC
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ADC TEMP1
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TAX
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TYA
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ADC #0
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TAY
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DEC TEMP0
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BNE POFFSL
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POFFSX: RTS
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;p0prep() - Prepare Player 0 for Display
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;Args: A - Y-Position
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; X,Y - Address of Graphics Data
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;Uses: ARLINS, P0LINS
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;Sets: TEMP0 - Y-Position
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;Affects; A,C,N,Z
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P0PREP: LSR ;Divide by 2 for Two-line Position
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STA TEMP0 ;Save Y Position
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ROL ;Rotate Carry into Bit 1
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EOR #1 ;Reverse It
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STA VDELP0 ;and Store in Vertical Delay Register
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LDA #ARLINS ;Draw = Top Line + Height - Y Position
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CLC
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ADC #P0LINS
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SEC
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SBC TEMP0
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STA P0DRAW
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TXA ;Pointer = GfxAddr + Height - 1 - Y Position
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CLC
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ADC #P0LINS-1
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TAX
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TYA
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ADC #0
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TAY
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TXA
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SEC
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SBC TEMP0
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STA P0PTRL
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TYA
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SBC #0
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STA P0PTRH
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RTS
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;p1prep() - Prepare Player 1 for Display
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;Args: A - Y-Position
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; X,Y - Address of Graphics Data
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;Uses: ARLINS, P1LINS
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;Sets: TEMP1 - Y-Position
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;Affects; A,C,N,Z
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P1PREP: CLC ;Add 1 to Y-Position
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ADC #1 ;to Compensate for GRP1 Priming
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LSR ;Divide by 2 for Two-line Position
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STA TEMP1 ;Save Y Position
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ROL ;Rotate Carry into Bit 1
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EOR #1 ;Reverse It
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STA VDELP1 ;and Store in Vertical Delay Register
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LDA #ARLINS ;Draw = Top Line + Height - Y Position + 1
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CLC
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ADC #P1LINS+1
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SEC
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SBC TEMP1
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STA P1DRAW
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TXA ;Pointer = GfxAddr + Height - 1 - Y Position
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CLC
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ADC #P1LINS-1
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TAX
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TYA
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ADC #0
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TAY
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TXA
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SEC
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SBC TEMP1
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STA P1PTRL
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TYA
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SBC #0
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STA P1PTRH
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RTS
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;ardisp() - Kernel Display Routine
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;Args: A = Playfield Color
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;Uses: ARLINS, P0LINS, P1LINS, P0PTRL, P1PTRL
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;Affects: A,X,Y,C,N,Z
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ARDISP: STA COLUPF
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LDY #ARLINS+1 ; 2 14 - Number of Kernal Lines (Scanlines / 2)
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LDX #$FF ; - Initialize Playfield Index
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LDA #1 ; - Reflect Playfield
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STA CTRLPF ; - Set Playfield Control Register
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LDA #P1LINS-1 ; - Preset GRP1 if Player 1 on Top Line
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DCP P1DRAW ;
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BCS ARDIS0 ;
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LDA #0 ;
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BYTE $2C ;
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ARDIS0: LDA (P1PTRL),Y ;
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STA GRP1 ; 3 6
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DEY ; 2 ??
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ARDISL: TYA ; 2 29 - Get Loop Counter
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AND #ARMULT-1 ; 2 31 - Mask Against Multiplier
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BNE ARDISS ; 2 33 If 0
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INX ; 2 35 - Increment Playfield Pointer
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ARDISS: LDA #P0LINS-1 ; 2 15 - Player 1 Height minus 1 due to STArting with 0
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DCP P0DRAW ; 5 20 - Decrement P0DRAW and compare with height
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BCS ARDIS1 ; 2 22 - If Player 0 not on Current Scanline
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LDA #0 ; 2 24 - Load 0 (No Graphics)
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BYTE $2C ; 4 28 - Else (BIT trick)
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ARDIS1: LDA (P0PTRL),Y ;(5 28)- Load Player 0 Graphics Line
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STA WSYNC ; 3 31 - Start Line 2
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STA GRP0 ; 3 3 - Set Player 0 Graphics Data
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LDA ARENA0,X ; 4 7 - get current scanline's playfield pattern
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STA PF0 ; 3 10 - @0-22 and update it
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LDA ARENA1,X ; 4 14 - get current scanline's playfield pattern
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STA PF1 ; 3 17 - @71-28 and update it
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LDA ARENA2,X ; 4 21 - get current scanline's playfield pattern
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STA PF2 ; 3 24 - @60-39
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LDA #P1LINS-1 ; 2 26 - Player 1 Height minus 1 due to STArting with 0
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DCP P1DRAW ; 5 31 - Load 0 (No Graphics)
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BCS ARDIS2 ; 2 33 - If Player 1 not on Current Scanline
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LDA #0 ; 2 35 - Load 0 (No Graphics)
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BYTE $2C ; 4 39 - Else (BIT trick)
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ARDIS2: LDA (P1PTRL),Y ;(5 39)- Load Player 1 Graphics Line
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STA WSYNC ; 3 42 - Start Line 2
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STA GRP1 ; 3 3 - Set Player 1 Graphics Data
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DEY ; 2 5 - Decrement Loop Counter
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BNE ARDISL ; 2 7 - and Loop if >= 0
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STY PF0 ; 3 10 - Clear Playfield
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STY PF1 ; 3 13 -
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STY PF2 ; 3 16 -
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RTS
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@ -0,0 +1,10 @@
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/* Two Line Kernal Arena Kernal for Atari 2600 *
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* Requires the following equates be set: *
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* ARNLNS - Number of Scanlines to Display *
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* P0HGHT - Height of Player 0 in Kernel Lines *
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* P1HGHT - Height of Player 1 in Kernel Lines */
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void p0prep(); //Prepare Player 0 for Display
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void p1prep(); //Prepare Player 1 for Display
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void ardisp(); //Display Arena
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@ -0,0 +1,11 @@
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;Bank Switching Registers
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BANK0 EQU $1FF4 ;Select Bank 0 (32K)
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BANK1 EQU $1FF5 ;Select Bank 1 (32K)
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BANK2 EQU $1FF6 ;Select Bank 2 (32K) Bank 0 (16K) Switch Banks (8K)
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BANK3 EQU $1FF7 ;Select Bank 3 (32K) Bank 1 (16K) Switch Banks (8K)
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BANK4 EQU $1FF8 ;Select Bank 4 (32K) Bank 2 (16K)
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BANK5 EQU $1FF9 ;Select Bank 5 (32K) Bank 3 (16K)
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BANK6 EQU $1FFA ;Select Bank 6 (32K)
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BANK7 EQU $1FFB ;Select Bank 7 (32K)
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@ -0,0 +1,22 @@
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;Atari 2600 Initialization Code - C02 Assembly Language File
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;Based on Batari Basic Initialization Code
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START: SEI ;Disable Interrupts
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CLD ;Disable Decimal Modes
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LDY #0 ;Set Y-Index to $00
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LDA $D0 ;If Location $D0
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CMP #$2C ; Does Not Contain $2C
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BNE IS2600 ;And
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LDA $D1 ; Location $D1
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CMP #$A9 ; Does Not Contain $D1
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BNE IS2600 ;Then
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DEY ; Set Y-Index to $FF
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IS2600: LDX #0 ;
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TXA ;
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CLRMEM: INX ;Clear TIA Registers and RAM
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TXS ; by Cycling Through All Stack Locations
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PHA ; and Pushing 0
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BNE CLRMEM ; which leaves Stack Pointer at $FF
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TYA ;Copy 2600 Flag to Accumulator
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JMP MAIN
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@ -0,0 +1,45 @@
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;colors.a02 - Atari 2600 Color/BW Assembly Language Routines
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;getclr(mask, clr, bw) - Get Color Based on Color B&W Switch Position
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;Args: A - Mask for Color Cycling (0=None)
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; Y - Color/Luminance to use in Color Mode
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; X - Color/Luminance to use in B&W Mode
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;Returns: Color to Use
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GETCLR: STA TEMP2 ;Save Color Cycling Mask
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LDA SWCHB ;Read Console Switches
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AND #%00001000 ;Test TV Type Switch
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BNE GETCLC ;If Off
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TXA ; Load B&W Mode Color/Luminance
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EOR TEMP2 ; Apply Mask
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AND #$0F ; and Strip High Nybble
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RTS ;Else
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GETCLC: TYA ; Load Color Mode Color/Luminance
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EOR TEMP2 ; and Apply Apply Mask
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RTS ;Return Selected Color
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;setclr(mask, &clrtbl) - Set Object Colors
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;Args: X,Y = Pointer to 8-Byte Color Table Color Table
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; Player0, Player1, Playfield, Background (Color)
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; Player0, Player1, Playfield, Background (B&W)
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;Sets: TEMP0,TEMP1 = Pointer to Color Table
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;Affects: A,X,Y,N,Z
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SETCLR: STY TEMP1 ;Save Pointer to Color Table
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STX TEMP0
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STA TEMP2 ;Save Color Cycling Mask
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LDX #3 ;Setting 4 colors (0-3)
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LDY #3 ;Refault to the color entries in the table (0-3)
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LDA SWCHB ;Read Console Switches
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AND #%00001000 ;Test TV Type Switch
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BNE SETCLL ;If On
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LDA #$0F ; Use Color Entries
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AND TEMP2 ;Else
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STA TEMP2 ; Strip High Nybble from Mask
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LDY #7 ; and Use B&W Entries
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SETCLL: LDA (TEMP0),Y ;Get Color/B&W Value
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EOR TEMP2 ;Apply Color Cycling Mask
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STA COLUP0,x ;and Set Object Color
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DEY ;Decrement Table Pointer
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DEX ;Decrement Register Pointer
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BPL SETCLL ;If >0, Loop
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RTS ;Return
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@ -0,0 +1,5 @@
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/* Atari 2600 Library Functions for C02 */
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void getclr(); //Select Color based on Color/B&W Switch
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void setclr(); //Set Colors from Color Table
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@ -0,0 +1,20 @@
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vcslib - Atari 2600 Library Functions for C02
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This library contains commonly used functions for the Atari VCS.
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setclr(&tbl); Sets all four system colors from array tbl,
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based on the position of the Color/B&W
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awitch.
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The array consists of 8 bytes of TIA
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Color/Luminance values, as follows:
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Player 0 (Color Mode)
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Player 1 (Color Mode)
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Playfield (Color Mode)
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Background (Color Mode)
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Player 0 (B&W Mode)
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Player 1 (B&W Mode)
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Playfield (B&W Mode)
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Background (B&W Mode)
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@ -0,0 +1,101 @@
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;===============================================================================
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; Digit Graphics
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;===============================================================================
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align 256
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DGTGFX: .byte %01110111
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.byte %01010101
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.byte %01010101
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.byte %01010101
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.byte %01110111
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.byte %00010001
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.byte %00010001
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.byte %00010001
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.byte %00010001
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.byte %00010001
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.byte %01110111
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.byte %00010001
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.byte %01110111
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.byte %01000100
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.byte %01110111
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.byte %01110111
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.byte %00010001
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.byte %00110011
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.byte %00010001
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.byte %01110111
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.byte %01010101
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.byte %01010101
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.byte %01110111
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.byte %00010001
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.byte %00010001
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.byte %01110111
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.byte %01000100
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.byte %01110111
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.byte %00010001
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.byte %01110111
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.byte %01110111
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.byte %01000100
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.byte %01110111
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.byte %01010101
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.byte %01110111
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.byte %01110111
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.byte %00010001
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.byte %00010001
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.byte %00010001
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.byte %00010001
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.byte %01110111
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.byte %01010101
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.byte %01110111
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.byte %01010101
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.byte %01110111
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.byte %01110111
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.byte %01010101
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.byte %01110111
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.byte %00010001
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.byte %01110111
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.byte %00100010
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.byte %01010101
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.byte %01110111
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.byte %01010101
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.byte %01010101
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.byte %01100110
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.byte %01010101
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.byte %01100110
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.byte %01010101
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.byte %01100110
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.byte %00110011
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.byte %01000100
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.byte %01000100
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.byte %01000100
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.byte %00110011
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.byte %01100110
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.byte %01010101
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.byte %01010101
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.byte %01010101
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.byte %01100110
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.byte %01110111
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.byte %01000100
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.byte %01100110
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.byte %01000100
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.byte %01110111
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.byte %01110111
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.byte %01000100
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.byte %01100110
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.byte %01000100
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.byte %01000100
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@ -1,6 +1,12 @@
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;k2line.a02 - Two Line Kernal Assembly Language File for C02
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;Requires ConSTAnts KNLLNS, P0HGHT and P1HGHT
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;Set Kernel Top Line
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;;TODO - Adjust for Extra WSYNC in DSPLNS
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;; Need to Execute a second WSYNC if KNLLNS is Even
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KNLTOP EQU KNLLNS/2-1 ;Kernel Lines / 2 Scanlines - 1 (Zero Based)
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P0DRAW EQU $D0 ;Player 0 Draw Counter
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P1DRAW EQU $D1 ;Player 1 Draw Counter
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P0PTRL EQU $D2 ;Player 0 Graphics Pointer
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@ -19,7 +25,7 @@ P0PREP: LSR ;Divide by 2 for Two-line Position
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ROL ;Rotate Carry into Bit 1
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EOR #1 ;Reverse It
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STA VDELP0 ;and Store in Vertical Delay Register
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LDA #KNLLNS-1 ;Draw = Top Line + Height - Y Position
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LDA #KNLTOP ;Draw = Top Line + Height - Y Position
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CLC
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ADC #P0HGHT
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SEC
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@ -54,7 +60,7 @@ P1PREP: CLC ;Add 1 to Y-Position
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ROL ;Rotate Carry into Bit 1
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EOR #1 ;Reverse It
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STA VDELP1 ;and Store in Vertical Delay Register
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LDA #KNLLNS-1 ;Draw = Top Line + Height - Y Position + 1
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LDA #KNLTOP ;Draw = Top Line + Height - Y Position + 1
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CLC
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ADC #P1HGHT+1
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SEC
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@ -80,7 +86,7 @@ P1PREP: CLC ;Add 1 to Y-Position
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;Args: None
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;Uses: KNLLNS, P0HGHT, P1HGHT, P0PTRL, P1PTRL
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;Affects: A,X,Y,C,N,Z
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DSPLNS: LDY #KNLLNS ; - Number of Kernal Lines (Scanlines / 2)
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DSPLNS: LDY #KNLTOP+1 ; - Number of Kernal Lines (Scanlines / 2)
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LDA #1 ; - Reflect Playfield
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STA CTRLPF ; - Set Playfield Control Register
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LDA #P1HGHT-1 ; - Preset GRP1 if Player 1 on Top Line
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@ -89,8 +95,6 @@ DSPLNS: LDY #KNLLNS ; - Number of Kernal Lines (Scanlines / 2)
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LDA #0 ;
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BYTE $2C ;
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DSPLN0: LDA (P1PTRL),Y ;
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STA WSYNC ; - Beginning of Line
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STA HMOVE ; 3 3 - Position Objects
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STA GRP1 ; 3 6
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DEY ; 2 8
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AND ($FF),Y ; 5 13 - Waste 5 Cycles to Match Line 2 Loop
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@ -0,0 +1,112 @@
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;k2line.a02 - Two Line Kernal Assembly Language File for C02
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;Requires Constants PLYR0H and PLYR1H,
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;Variables PLYR0D and PLYR1D, and Pointers PLYR0P and PLYR1P
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PLYR0H EQU $D0 ;Player 0 Height
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PLYR1H EQU $D1 ;Player 1 Height
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PLYR0D EQU $D2 ;Player 0 Draw Counter
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PLYR1D EQU $D3 ;Player 1 Draw Pointer
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PLYR0P EQU $D4 ;Player 0 Graphics Pointer
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PLYR1P EQU $D6 ;Player 1 Graphics Pointer
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PLYR0T EQU $D8 ;Player 0 Pointer Offset
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PLYR1T EQU $DA ;Player 1 Pointer Offset
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SCNLNS EQU $DF ;Number of Scanlines
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;setpl0() - Set Player 0 Data
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;Args: A = Player 0 Height
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; Y,X = Pointer to Player 0 Graphics Data
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SETPL0: STA PLYR0H ;Save Player 0 Height
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DEC PLYR0H ;and Decrement
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STX PLYR0P ;Save Player 0 Pointer
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STY PLYR0P+1
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RTS
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;setpl1() - Set Player 1 Data
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;Args: A = Player 1 Height
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; Y,X = Pointer to Player 1 Graphics Data
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SETPL1: STA PLYR1H ;Save Player 1 Height
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DEC PLYR1H ;and Decrement
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STX PLYR1P ;Save Player 1 Pointer
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STY PLYR1P+1
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RTS
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;prppl0() - Prep Player Variables
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;Args: A = Player 0 Y-Position
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||||
PRPPL0: STA TEMP0
|
||||
LDA SCNLNS ;PLYR0D = SCNLNS + PLYR0H - PLYR0Y
|
||||
CLC
|
||||
ADC PLYR0H
|
||||
; ADC #1
|
||||
SEC
|
||||
SBC TEMP0
|
||||
STA PLYR0D
|
||||
LDA PLYR0P ;PLYR0T = PLYR0P + PLYR0H - PLYR0Y - 1
|
||||
CLC
|
||||
ADC PLYR0H
|
||||
SEC
|
||||
SBC TEMP0
|
||||
STA PLYR0T
|
||||
LDA PLYR0P+1
|
||||
SBC #0
|
||||
STA PLYR0T+1
|
||||
RTS
|
||||
|
||||
;prppl1() - Prep Player 1 Variables
|
||||
;Args: A = Player 1 Y Position
|
||||
PRPPL1: STA TEMP1
|
||||
LDA SCNLNS ;PLYR1D = SCNLNS + PLYR1H - PLYR1Y
|
||||
CLC
|
||||
ADC PLYR1H
|
||||
; ADC #1
|
||||
SEC
|
||||
SBC TEMP1
|
||||
STA PLYR1D
|
||||
LDA PLYR1P ;PLYR1T = PLYR1P + PLYR1H - PLYR1Y - 1
|
||||
CLC
|
||||
ADC PLYR1H
|
||||
SEC
|
||||
SBC TEMP1
|
||||
STA PLYR1T
|
||||
LDA PLYR1P+1
|
||||
SBC #0
|
||||
STA PLYR1T+1
|
||||
RTS
|
||||
|
||||
;prpdsp() - Prep Display
|
||||
PRPDSP: LDA #0
|
||||
STA WSYNC ;Wait for Horizontal Sync
|
||||
STA HMOVE ;Move Objects
|
||||
STA VDELP0 ;Clear Player 0 Vertical Delay
|
||||
RTS
|
||||
|
||||
;dsplns() - Display Two Line Kernal
|
||||
DSPLNS: LDY SCNLNS ; (13) Set Number of Lines to Draw
|
||||
DEY
|
||||
DSPLNL: LDA PLYR0H ;2 21 - Height of Player 0 (Zero Based)
|
||||
DCP PLYR0D ;5 26 - Decrement PLYR0D and compare with height
|
||||
BCS DSPLN0 ;2 28 - (3 23) If Player 0 not on Current Scanline
|
||||
LDA #0 ;2 30 - Load Blank Line
|
||||
BYTE $2C ;4 34 - Else (BIT trick)
|
||||
DSPLN0: LDA (PLYR0T),Y ;5 49 - Load Player 0 Graphics Line
|
||||
STA WSYNC ;3 52 - End of Line 2
|
||||
STA GRP0 ;3 3 - Set Player 0 Graphics Data
|
||||
LDX #%11111111 ;2 5 - Load Playfield Pattern
|
||||
STX PF0 ;3 8 - and Store
|
||||
STX PF1 ;3 11
|
||||
STX PF2 ;3 14
|
||||
LDA PLYR1H ;2 16 - Height of Player 1
|
||||
DCP PLYR1D ;5 21 - Decrement PLYR1D and compare with height
|
||||
BCS DSPLN1 ;2 23 - (3 18) If Player 0 not on Current Scanline
|
||||
LDA #0 ;2 25 - Load Blank Line
|
||||
BYTE $2C ;4 29 - - Else (BIT trick)
|
||||
DSPLN1 LDA (PLYR1T),Y ;5 34 - Load Player 1 Graphics Line
|
||||
STA WSYNC ;3 37 - End of Line 1
|
||||
STA GRP1 ;3 3 - Set Player 0 Graphics Data
|
||||
LDX #0 ;2 5 - Load Playfield Pattern
|
||||
STX PF0 ;3 8 - and Store
|
||||
STX PF1 ;3 11
|
||||
STX PF2 ;3 14
|
||||
DEY ;2 16 - decrease the 2LK loop counter
|
||||
BPL DSPLNL ;2 18 - (3 21) Branch if more lines to draw
|
||||
RTS
|
||||
|
||||
|
|
@ -0,0 +1,131 @@
|
|||
;k2line.a02 - Two Line Kernal Assembly Language File for C02
|
||||
;Requires Constants PLYR0H and PLYR1H,
|
||||
;Variables PLYR0D and PLYR1D, and Pointers PLYR0P and PLYR1P
|
||||
|
||||
PLYR0H EQU $D0 ;Player 0 Height
|
||||
PLYR1H EQU $D1 ;Player 1 Height
|
||||
PLYR0D EQU $D2 ;Player 0 Draw Counter
|
||||
PLYR1D EQU $D3 ;Player 1 Draw Pointer
|
||||
PLYR0P EQU $D4 ;Player 0 Graphics Pointer
|
||||
PLYR1P EQU $D6 ;Player 1 Graphics Pointer
|
||||
PLYR0T EQU $D8 ;Player 0 Pointer Offset
|
||||
PLYR1T EQU $DA ;Player 1 Pointer Offset
|
||||
SCNLNS EQU $DF ;Number of Scanlines
|
||||
|
||||
;setpl0() - Set Player 0 Data
|
||||
;Args: A = Player 0 Height
|
||||
; Y,X = Pointer to Player 0 Graphics Data
|
||||
SETPL0: STA PLYR0H ;Save Player 0 Height
|
||||
DEC PLYR0H ;and Decrement
|
||||
STX PLYR0P ;Save Player 0 Pointer
|
||||
STY PLYR0P+1
|
||||
RTS
|
||||
|
||||
;setpl1() - Set Player 1 Data
|
||||
;Args: A = Player 1 Height
|
||||
; Y,X = Pointer to Player 1 Graphics Data
|
||||
SETPL1: STA PLYR1H ;Save Player 1 Height
|
||||
DEC PLYR1H ;and Decrement
|
||||
STX PLYR1P ;Save Player 1 Pointer
|
||||
STY PLYR1P+1
|
||||
RTS
|
||||
|
||||
;prppl0() - Prep Player Variables
|
||||
;Args: A = Player 0 Y-Position
|
||||
PRPPL0: LDX #1 ;Divide Y-Position by 2
|
||||
SEC
|
||||
SBC #1
|
||||
LSR ;and Set Vertical Delay if No Remainder
|
||||
STA TEMP0
|
||||
BCS PRPPN0
|
||||
STX VDELP0
|
||||
PRPPN0: LDA SCNLNS ;PLYR0D = SCNLNS + PLYR0H - PLYR0Y
|
||||
CLC
|
||||
ADC PLYR0H
|
||||
SEC
|
||||
SBC TEMP0
|
||||
STA PLYR0D
|
||||
LDA PLYR0P ;PLYR0T = PLYR0P + PLYR0H - PLYR0Y - 1
|
||||
CLC
|
||||
ADC PLYR0H
|
||||
SEC
|
||||
SBC TEMP0
|
||||
STA PLYR0T
|
||||
LDA PLYR0P+1
|
||||
SBC #0
|
||||
STA PLYR0T+1
|
||||
RTS
|
||||
|
||||
;prppl1() - Prep Player 1 Variables
|
||||
;Args: A = Player 1 Y Position
|
||||
PRPPL1: LDX #1
|
||||
CLC ;Increment Y-Position
|
||||
ADC #1 ; to compensate for priming of GRP1
|
||||
LSR ;Divide by 2
|
||||
STA TEMP1 ; and set Vertical Delay if No Remainder
|
||||
BCS PRPPN1
|
||||
STX VDELP1
|
||||
PRPPN1: LDA SCNLNS ;PLYR1D = SCNLNS + PLYR1H - PLYR1Y
|
||||
CLC
|
||||
ADC #1
|
||||
ADC PLYR1H
|
||||
SEC
|
||||
SBC TEMP1
|
||||
STA PLYR1D
|
||||
LDA PLYR1P ;PLYR1T = PLYR1P + PLYR1H - PLYR1Y - 1
|
||||
CLC
|
||||
ADC PLYR1H
|
||||
SEC
|
||||
SBC TEMP1
|
||||
STA PLYR1T
|
||||
LDA PLYR1P+1
|
||||
SBC #
|
||||
STA PLYR1T+1
|
||||
RTS
|
||||
|
||||
;prpdsp() - Prep Display
|
||||
PRPDSP: LDA #0
|
||||
STA WSYNC ;Wait for Horizontal Sync
|
||||
STA HMOVE ;Move Objects
|
||||
STA VDELP0 ;Clear Player 0 Vertical Delay
|
||||
STA VDELP1 ;Clear Player 0 Vertical Delay
|
||||
RTS
|
||||
|
||||
;dsplns() - Display Two Line Kernal
|
||||
DSPLNS: LDY SCNLNS ; (13) Set Number of Lines to Draw
|
||||
LDA PLYR1H ; 2 9 - Get Player 1 Height
|
||||
DCP PLYR1D ; 5 14 - Decrement counter and compare with height
|
||||
BCS DSPLNP ; 2 16 - (3 18) If not on current scanline
|
||||
LDA #0 ; 2 18 - Load Blank Line
|
||||
BYTE $2C ; 4 22 - Else (BIT trick)
|
||||
DSPLNP: LDA (PLYR1T),Y ; 5 22 - Load Player 0 Graphics Line
|
||||
STA GRP1 ; 3 25 - Set Player 0 Graphics Data
|
||||
DEY
|
||||
DSPLNL: LDA PLYR0H ;2 21 - Height of Player 0 (Zero Based)
|
||||
DCP PLYR0D ;5 26 - Decrement counter and compare with height
|
||||
BCS DSPLN0 ;2 28 - (3 23) If Player 0 not on Current Scanline
|
||||
LDA #0 ;2 30 - Load Blank Line
|
||||
BYTE $2C ;4 34 - Else (BIT trick)
|
||||
DSPLN0: LDA (PLYR0T),Y ;5 49 - Load Player 0 Graphics Line
|
||||
STA WSYNC ;3 52 - End of Line 2
|
||||
STA GRP0 ;3 3 - Set Player 0 Graphics Data
|
||||
LDX #%11111111 ;2 5 - Load Playfield Pattern
|
||||
STX PF0 ;3 8 - and Store
|
||||
STX PF1 ;3 11
|
||||
STX PF2 ;3 14
|
||||
LDA PLYR1H ;2 16 - Get Player 1 Height
|
||||
DCP PLYR1D ;5 21 - Decrement counter and compare with height
|
||||
BCS DSPLN1 ;2 23 - (3 18) If not on current scanline
|
||||
LDA #0 ;2 25 - Load Blank Line
|
||||
BYTE $2C ;4 29 - - Else (BIT trick)
|
||||
DSPLN1 LDA (PLYR1T),Y ;5 34 - Load Player 1 Graphics Line
|
||||
STA WSYNC ;3 37 - End of Line 1
|
||||
STA GRP1 ;3 3 - Set Player 0 Graphics Data
|
||||
LDX #0 ;2 5 - Load Playfield Pattern
|
||||
STX PF0 ;3 8 - and Store
|
||||
STX PF1 ;3 11
|
||||
STX PF2 ;3 14
|
||||
DEY ;2 16 - decrease the 2LK loop counter
|
||||
BPL DSPLNL ;2 18 - (3 21) Branch if more lines to draw
|
||||
RTS
|
||||
|
||||
|
|
@ -0,0 +1,106 @@
|
|||
processor 6502
|
||||
include "vcs.h"
|
||||
include "macro.h"
|
||||
SEG
|
||||
ORG $F000
|
||||
Reset
|
||||
StartOfFrame
|
||||
; Start of vertical blank processing
|
||||
lda #0
|
||||
sta VBLANK
|
||||
lda #2
|
||||
sta VSYNC
|
||||
|
||||
; 3 scanlines of VSYNCH signal...
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
lda #0
|
||||
sta VSYNC
|
||||
; 37 scanlines of vertical blank...
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
|
||||
; 192 scanlines of picture...
|
||||
|
||||
ldx #0
|
||||
REPEAT 192; scanlines
|
||||
inx
|
||||
stx COLUBK
|
||||
sta WSYNC
|
||||
REPEND
|
||||
|
||||
lda #%01000010
|
||||
sta VBLANK ; end of screen - enter blanking
|
||||
; 30 scanlines of overscan...
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
sta WSYNC
|
||||
jmp StartOfFrame
|
||||
ORG $FFFA
|
||||
.word Reset ; NMI
|
||||
.word Reset ; RESET
|
||||
.word Reset ; IRQ
|
||||
END
|
||||
|
|
@ -0,0 +1,5 @@
|
|||
Timer Setting
|
||||
76/64 = 38/32 = 19/16
|
||||
X*19 = X*16 + X*2 + X*1
|
||||
|
||||
|
||||
|
|
@ -0,0 +1,6 @@
|
|||
;Atari VCS Supercharger Assembly Language Routines
|
||||
|
||||
SCCTL EQU $FFF8 ;Supercharger Control Register
|
||||
SCAUD EQU $FFF9 ;Supercharger Audio Data
|
||||
|
||||
|
||||
|
|
@ -1,19 +1,18 @@
|
|||
;Atari 2600 Two Player Score Kernel
|
||||
|
||||
;Score Routine Variables
|
||||
SCORE0 EQU $E8 ;Player One Score
|
||||
SCORE1 EQU $E9 ;Player Two Score
|
||||
SC0ONE EQU $EA ;One Score Ones Digit Offset
|
||||
SC1ONE EQU $EB ;Player Ten Score Ones Digit Offset
|
||||
SC0TEN EQU $EC ;Player One Score Ones Digit Offset
|
||||
SC1TEN EQU $ED ;Player Ten Score Ones Digit Offset
|
||||
SC0GFX EQU $EE ;Player One Score Graphics Data
|
||||
SC1GFX EQU $EF ;Player Two Score Graphics Data
|
||||
|
||||
SCORE0 EQU $E8 ;Player One Score
|
||||
SCORE1 EQU $E9 ;Player Two Score
|
||||
SC0ONE EQU $EA ;One Score Ones Digit Offset
|
||||
SC1ONE EQU $EB ;Player Ten Score Ones Digit Offset
|
||||
SC0TEN EQU $EC ;Player One Score Ones Digit Offset
|
||||
SC1TEN EQU $ED ;Player Ten Score Ones Digit Offset
|
||||
SC0GFX EQU $EE ;Player One Score Graphics Data
|
||||
SC1GFX EQU $EF ;Player Two Score Graphics Data
|
||||
|
||||
;Prep Scores For Diplay
|
||||
SCRPRP: LDX #1 ;Offset into SCORE0/SCORE1
|
||||
SCRPRL: LDA SCORE0,X ;Get SCORE1 (First Pass) or SCORE0 (Second Pass)
|
||||
SCPREP: LDX #1 ;Offset into SCORE0/SCORE1
|
||||
SCPREL: LDA SCORE0,X ;Get SCORE1 (First Pass) or SCORE0 (Second Pass)
|
||||
AND #$0F ;Remove Tens Digit
|
||||
STA TEMP0 ;And Save It
|
||||
ASL ;Multiply By 4
|
||||
|
|
@ -30,14 +29,14 @@ SCRPRL: LDA SCORE0,X ;Get SCORE1 (First Pass) or SCORE0 (Second Pass)
|
|||
ADC TEMP0 ;Add Saved Value, Resulting in Digit / 16 * 5
|
||||
STA SC0TEN,X ;Store in SC0TEN (First Pass) or SC1TEN (Second Pass)
|
||||
DEX ;Point to SCORE 1
|
||||
BPL SCRPRL ;AND Loop if >0
|
||||
BPL SCPREL ;AND Loop if >0
|
||||
RTS ;Return
|
||||
|
||||
;Display Score Kernel - Uses 12 Lines Total
|
||||
SCRDSP: LDA #2 ; - Use Player Colors
|
||||
;scdisp() - Score Display Kernel - Uses 12 Scanlines Total
|
||||
SCDISP: LDA #2 ; - Use Player Colors
|
||||
STA CTRLPF ; - Set Playfield Control Register
|
||||
LDX #5 ; 43 - cycle after looping
|
||||
SCRDSL: LDY SC0TEN ; 3 46 - get the tens digit offset for the Score
|
||||
SCDISL: LDY SC0TEN ; 3 46 - get the tens digit offset for the Score
|
||||
LDA DGTGFX,Y ; 5 51 - use it to load the digit graphics
|
||||
AND #$F0 ; 2 53 - remove the graphics for the ones digit
|
||||
STA SC0GFX ; 3 56 - AND save it
|
||||
|
|
@ -57,7 +56,7 @@ SCRDSL: LDY SC0TEN ; 3 46 - get the tens digit offset for the Score
|
|||
AND #$0F ; 2 26 - remove the graphics for the tens digit
|
||||
ORA SC1GFX ; 3 29 - merge with the tens digit graphics
|
||||
STA SC1GFX ; 3 32 - AND save it
|
||||
JSR SCRDSR ;12 44 - waste 12 cycles
|
||||
JSR SCDISX ;12 44 - waste 12 cycles
|
||||
STA PF1 ; 3 47 - @39-54, update playfield for Timer display
|
||||
LDY SC0GFX ; 3 50 - preload for next scanline
|
||||
STA WSYNC ; 3 53 - wait for end of scanline
|
||||
|
|
@ -66,12 +65,12 @@ SCRDSL: LDY SC0TEN ; 3 46 - get the tens digit offset for the Score
|
|||
INC SC1TEN ; 5 13 - advance for the next line of graphic data
|
||||
INC SC0ONE ; 5 18 - advance for the next line of graphic data
|
||||
INC SC1ONE ; 5 23 - advance for the next line of graphic data
|
||||
JSR SCRDSR ;12 35 - waste 12 cycles
|
||||
JSR SCDISX ;12 35 - waste 12 cycles
|
||||
DEX ; 2 37 - decrease the loop counter
|
||||
STA PF1 ; 3 40 - @39-54, update playfield for the Timer display
|
||||
BNE SCRDSL ; 2 42 - (3 43) if dex != 0 then branch to ScoreLoop
|
||||
BNE SCDISL ; 2 42 - (3 43) if dex != 0 then branch to ScoreLoop
|
||||
STA WSYNC ; 3 45 - wait for end of scanline
|
||||
STX PF1 ; 3 3 - x = 0, so this blanks out playfield
|
||||
STA WSYNC ; 3 6 - wait for end of scanline
|
||||
SCRDSR: RTS ; 6 12 - Return
|
||||
SCDISX: RTS ; 6 12 - Return
|
||||
|
||||
|
|
|
|||
|
|
@ -1,13 +1,5 @@
|
|||
/* Atari 2600 Two-Player Score Kernel */
|
||||
|
||||
char score1; //Player One Score
|
||||
char score2; //Player Two Score
|
||||
|
||||
char sc1one; //Player One Score Ones Digit Offset
|
||||
char sc1ten; //Player One Score Ones Digit Offset
|
||||
char sc2one; //Player Ten Score Ones Digit Offset
|
||||
char sc2ten; //Player Ten Score Ones Digit Offset
|
||||
|
||||
char sc1gfx; //Player One Score Graphics Data
|
||||
char sc2gfx; //Player Two Score Graphics Data
|
||||
char score0; //Player One Score
|
||||
char score1; //Player Two Score
|
||||
|
||||
|
|
|
|||
|
|
@ -0,0 +1,204 @@
|
|||
;Atari 2600 Initialization Code - C02 Assembly Language File
|
||||
|
||||
PLR0X EQU $80
|
||||
PLR1X EQU $81
|
||||
MSL0X EQU $82
|
||||
MSL1X EQU $83
|
||||
BALLX EQU $84
|
||||
|
||||
OBJTY EQU $85
|
||||
PLR0Y EQU $85
|
||||
PLR1Y EQU $86
|
||||
MSL1HT EQU $87
|
||||
MSL1Y EQU $88
|
||||
BALLY EQU $89
|
||||
|
||||
PLR0LO EQU $8A
|
||||
PLR0HI EQU $8B
|
||||
PLR1LO EQU $8C
|
||||
PLR1HI EQU $8D
|
||||
|
||||
PLR0HT EQU $8E
|
||||
PLR1HT EQU $8F
|
||||
MSL0HT EQU $90
|
||||
MSL0Y EQU $91
|
||||
BALLHT EQU $92
|
||||
|
||||
|
||||
SCORE EQU $93 ; $93-$95
|
||||
SCOREPOINTERS EQU $96 ; $96-$9B EQU 6 BYTES
|
||||
TEMP1 EQU $9C ;USED BY KERNEL
|
||||
TEMP2 EQU $9D ;CAN BE USED IN PROGRAM TOO, BUT
|
||||
TEMP3 EQU $9E ;ARE OBLITERATED WHEN DRAWSCREEN IS CALLED.
|
||||
TEMP4 EQU $9F
|
||||
TEMP5 EQU $A0
|
||||
TEMP6 EQU $A1
|
||||
|
||||
RAND EQU $A2
|
||||
SCORECOLOR EQU $A3
|
||||
|
||||
VAR0 EQU $A4
|
||||
VAR1 EQU $A5
|
||||
VAR2 EQU $A6
|
||||
VAR3 EQU $A7
|
||||
VAR4 EQU $A8
|
||||
VAR5 EQU $A9
|
||||
VAR6 EQU $AA
|
||||
VAR7 EQU $AB
|
||||
VAR8 EQU $AC
|
||||
VAR9 EQU $AD
|
||||
VAR10 EQU $AE
|
||||
VAR11 EQU $AF
|
||||
VAR12 EQU $B0
|
||||
VAR13 EQU $B1
|
||||
VAR14 EQU $B2
|
||||
VAR15 EQU $B3
|
||||
VAR16 EQU $B4
|
||||
VAR17 EQU $B5
|
||||
VAR18 EQU $B6
|
||||
VAR19 EQU $B7
|
||||
VAR20 EQU $B8
|
||||
VAR21 EQU $B9
|
||||
VAR22 EQU $BA
|
||||
VAR23 EQU $BB
|
||||
VAR24 EQU $BC
|
||||
VAR25 EQU $BD
|
||||
VAR26 EQU $BE
|
||||
VAR27 EQU $BF
|
||||
VAR28 EQU $C0
|
||||
VAR29 EQU $C1
|
||||
VAR30 EQU $C2
|
||||
VAR31 EQU $C3
|
||||
VAR32 EQU $C4
|
||||
VAR33 EQU $C5
|
||||
VAR34 EQU $C6
|
||||
VAR35 EQU $C7
|
||||
VAR36 EQU $C8
|
||||
VAR37 EQU $C9
|
||||
VAR38 EQU $CA
|
||||
VAR39 EQU $CB
|
||||
VAR40 EQU $CC
|
||||
VAR41 EQU $CD
|
||||
VAR42 EQU $CE
|
||||
VAR43 EQU $CF
|
||||
VAR44 EQU $D0
|
||||
VAR45 EQU $D1
|
||||
VAR46 EQU $D2
|
||||
VAR47 EQU $D3
|
||||
|
||||
TEMP7 EQU $D4 ; THIS IS USED TO AID IN BANKSWITCHING
|
||||
|
||||
PLAYFIELDPOS EQU $D5
|
||||
|
||||
A EQU $D6
|
||||
B EQU $D7
|
||||
C EQU $D8
|
||||
D EQU $D9
|
||||
E EQU $DA
|
||||
F EQU $DB
|
||||
G EQU $DC
|
||||
H EQU $DD
|
||||
I EQU $DE
|
||||
J EQU $DF
|
||||
K EQU $E0
|
||||
L EQU $E1
|
||||
M EQU $E2
|
||||
N EQU $E3
|
||||
O EQU $E4
|
||||
P EQU $E5
|
||||
Q EQU $E6
|
||||
R EQU $E7
|
||||
S EQU $E8
|
||||
T EQU $E9
|
||||
U EQU $EA
|
||||
V EQU $EB
|
||||
W EQU $EC
|
||||
X EQU $ED
|
||||
Y EQU $EE
|
||||
Z EQU $EF
|
||||
|
||||
; AVAILABLE FOR OTHER USES, OR IF UNUSED, PROVIDE MORE STACK SPACE
|
||||
|
||||
AUX1 EQU $F0
|
||||
AUX2 EQU $F1
|
||||
AUX3 EQU $F2
|
||||
AUX4 EQU $F3
|
||||
AUX5 EQU $F4
|
||||
AUX6 EQU $F5
|
||||
|
||||
; PLAYFIELD COLOR/HT POINTERS
|
||||
PFCOLORTABLE EQU $F0 ; AND $D5
|
||||
PFHTTABLE EQU $F0 ; AND $D5
|
||||
; THE ABOVE POINTERS ARE THE SAME BECAUSE IF COLOR AND HT ARE BOTH USED TOGETHER,
|
||||
; THEY MUST USED ABSOLUTE INDEXED AND CANNOT USE POINTERS
|
||||
|
||||
LIFEPOINTER EQU $F2 ; POINTER TO "LIVES" SHAPE
|
||||
; UPPER 3 BITS OF $F2 CONTAIN THE NUMBER OF LIVES
|
||||
LIFECOLOR EQU $F4
|
||||
LIVES EQU $F3 ; # LIVES >> 5
|
||||
STATUSBARLENGTH EQU $F5 ; ONLY USES UPPER 5 BITS; OTHER BITS FREE
|
||||
|
||||
PFSCORE1 EQU $F2 ; OPTIONAL PLAYFIELD BYTES IN SCORE
|
||||
PFSCORE2 EQU $F3
|
||||
PFSCORECOLOR EQU $F4
|
||||
|
||||
STACK1 EQU $F6
|
||||
STACK2 EQU $F7
|
||||
STACK3 EQU $F8
|
||||
STACK4 EQU $F9
|
||||
|
||||
|
||||
START: SEI ;Disable Interrupts
|
||||
CLD ;Disable Decimal Modes
|
||||
LDY #0 ;Set Y-Index to $00
|
||||
LDA $D0 ;If Location $D0
|
||||
CMP #$2C ; Does Not Contain $2C
|
||||
BNE IS2600 ;And
|
||||
LDA $D1 ; Location $D1
|
||||
CMP #$A9 ; Does Not Contain $D1
|
||||
BNE IS2600 ;Then
|
||||
DEY ; Set Y-Index to $FF
|
||||
IS2600: LDX #0 ;Initialize X-Index
|
||||
TXA ;Initialize Accumulator
|
||||
CLRMEM: INX ;
|
||||
TXS ;
|
||||
PHA
|
||||
BNE CLRMEM
|
||||
STY TEMP1
|
||||
IFCONST PFROWHT
|
||||
LDA PFROWHT
|
||||
ELSE
|
||||
IFCONST PFRES
|
||||
LDA #(96/PFRES)
|
||||
ELSE
|
||||
LDA #8
|
||||
ENDIF
|
||||
ENDIF
|
||||
STA PLAYFIELDPOS
|
||||
LDX #5
|
||||
INITSCORE
|
||||
LDA #<SCORETABLE
|
||||
STA SCOREPOINTERS,X
|
||||
DEX
|
||||
BPL INITSCORE
|
||||
LDA #1
|
||||
STA CTRLPF
|
||||
ORA INTIM
|
||||
STA RAND
|
||||
|
||||
IFCONST MULTISPRITE
|
||||
JSR MULTISPRITE_SETUP
|
||||
ENDIF
|
||||
|
||||
IFNCONST BANKSWITCH
|
||||
JMP GAME
|
||||
ELSE
|
||||
LDA #>(GAME-1)
|
||||
PHA
|
||||
LDA #<(GAME-1)
|
||||
PHA
|
||||
PHA
|
||||
PHA
|
||||
LDX #1
|
||||
JMP BS_JSR
|
||||
ENDIF
|
||||
|
|
@ -0,0 +1,27 @@
|
|||
;C02 VCS Library - Joystick Assembly Language Subroutines
|
||||
|
||||
;getstk(cntrlr) - Read Joystick
|
||||
;Args: A = Controller Number, 0=Left, 1=Right
|
||||
;Sets: TEMP0 = Left Joystick Raw Directional Bits
|
||||
; TEMP1 = Right Joystick Raw Directional Bits
|
||||
; X = Controller Number
|
||||
;Returns: A = Joystick Bits (1 if Pressed)
|
||||
; 0=Up, 1=Down, 2=Left, 3=Right, 7=Trigger
|
||||
; N = Set if Trigger Pressed
|
||||
; Z = Set if No Buttons or Trigger Pressed
|
||||
GETSTK: TAX ;Save Stick Number in Index
|
||||
LDA SWCHA ;Read Joystick Register
|
||||
LSR ;Shift High Nybble into Low Nybble
|
||||
LSR
|
||||
LSR
|
||||
LSR
|
||||
STA TEMP0 ;Save Left Joystick Raw Bits
|
||||
LDA SWCHA ;Read Joystick Register
|
||||
AND #$0F ;Strip High Nybble
|
||||
STA TEMP1 ;Save Right Joystick Raw Bits
|
||||
LDA INPT4,X ;Read Joystick Trigger
|
||||
AND #$80 ;Strip Bits 1-6
|
||||
ORA TEMP0,X ;Combine with Directional Bits
|
||||
EOR #$8F ;Reverse Bits
|
||||
RTS
|
||||
|
||||
|
|
@ -0,0 +1,10 @@
|
|||
/* Atari 2600 Joystick Functions for C02 */
|
||||
|
||||
//Joystick Directions
|
||||
//#define STKUP = 1 //Joystick Up
|
||||
//#define STKDN = 2 //Joystick Down
|
||||
//#define STKLF = 4 //Joystick Left
|
||||
//#define STKRT = 8 //Joystick Right
|
||||
|
||||
char getstk(); //Read Joystick
|
||||
|
||||
|
|
@ -0,0 +1,31 @@
|
|||
sticks - Atari 2600 Joystick Functions for C02
|
||||
|
||||
This library contains a function for reading the joysticks:
|
||||
|
||||
res = getstk(cntrlr); Reads the state of the specified joystick.
|
||||
|
||||
The joystick to be read is specified by
|
||||
the argument cntrlr:
|
||||
0 = Left Joystick
|
||||
1 = Right Joystick
|
||||
|
||||
Returns a byte comprised of the bits:
|
||||
Bit Hex Dec Control
|
||||
0 $01 1 Up
|
||||
1 $02 2 Down
|
||||
2 $03 4 Left
|
||||
3 $04 8 Right
|
||||
7 $05 128 Trigger
|
||||
|
||||
A 1 in a bit means that the direction
|
||||
or trigger is pressed, so the function
|
||||
will return 0 if they joystick is
|
||||
centered and the trigger is not pressed.
|
||||
This is the reverse of the raw bits from
|
||||
the hardware ports.
|
||||
|
||||
Note: The raw bits for the left joystick
|
||||
are stored in TEMP0, while the raw bits
|
||||
for the right joystick are stored in TEMP1.
|
||||
|
||||
|
||||
|
|
@ -0,0 +1,71 @@
|
|||
;Atari 2600 Timer Bar Kernel
|
||||
|
||||
;Timer Variables
|
||||
TMRPF0 EQU $F0 ;Timer Playfield Leftmost Byte
|
||||
TMRPF1 EQU $F1
|
||||
TMRPF2 EQU $F2
|
||||
TMRPF3 EQU $F3
|
||||
TMRPF4 EQU $F4
|
||||
TMRPF5 EQU $F5 ;Timer Playfield Rightmost Byte
|
||||
|
||||
;tmprep() - Prepare Timer Bar
|
||||
TMPREP: LDA #%11111111
|
||||
STA TMRPF0
|
||||
STA TMRPF1
|
||||
STA TMRPF2
|
||||
STA TMRPF3
|
||||
STA TMRPF4
|
||||
STA TMRPF5
|
||||
RTS
|
||||
|
||||
;tmtick() - Tick Down Timer Bar
|
||||
;Returns: A=$FF If Timer has Not Expired
|
||||
; $00 If Timer has Expired
|
||||
TMTICK: LDA TMRPF0 ;Check Leftmost Nybble of Timer Bar
|
||||
AND #$F0 ;If 0
|
||||
BEQ TMTICX ; Return FALSE
|
||||
LSR TMRPF5 ;PF2 right side, reversed bits so shift right
|
||||
ROL TMRPF4 ;PF1 right side, normal bits so shift left
|
||||
ROR TMRPF3 ;PF0 right side, reversed bits so shift right
|
||||
LDA TMRPF3 ;only upper nybble used, so we need to put bit 3 into C
|
||||
LSR
|
||||
LSR
|
||||
LSR
|
||||
LSR
|
||||
ROR TMRPF2 ;PF2 left side, reversed bits so shift right
|
||||
ROL TMRPF1 ;PF1 left side, normal bits so shift left
|
||||
ROR TMRPF0 ;PF0 left side, reversed bits so shift right
|
||||
LDA #$FF ;Return TRUE
|
||||
TMTICX: RTS
|
||||
|
||||
;tmdisp() - Display Timer Bar
|
||||
;Args: A = Timer Bar Color
|
||||
TMDISP: STA COLUPF ; - Set Playfield Color
|
||||
LDX #0 ; - Offset for Writes
|
||||
STX CTRLPF ; - Set Playfield to Defaults
|
||||
LDY #1 ; - Use Two Scanlines
|
||||
TMDISL: STA WSYNC ; - Wait for Beginning of Line
|
||||
LDA TMRPF0,X ; 4 4 - Copy Data to Playfield Left
|
||||
STA PF0,X ; 5 9 - Indexed Mode Uses Extra Cycles
|
||||
LDA TMRPF1,X ; 4 13
|
||||
STA PF1,X ; 5 18
|
||||
LDA TMRPF2,X ; 4 22
|
||||
STA PF2,X ; 5 27
|
||||
JSR TMDISX ;12 39 - Wait 12 Cycles
|
||||
LDA TMRPF3 ; 3 42 - Copy Data To Playfield Right
|
||||
STA PF0 ; 3 45
|
||||
LDA TMRPF4 ; 3 50
|
||||
STA PF1 ; 3 53
|
||||
LDA TMRPF5 ; 3 56
|
||||
STA PF2 ; 3 59
|
||||
DEY ; 2 62
|
||||
BPL TMDISL ; 2 64 (3 65)
|
||||
STA WSYNC ; 3 67
|
||||
LDA #0 ; 2 2
|
||||
STA PF0 ; 3 5
|
||||
STA PF1 ; 3 8
|
||||
STA PF2 ; 3 11
|
||||
STA COLUPF ; 3 14
|
||||
STA WSYNC ; 3 20 - Gap between timer and Arena
|
||||
TMDISX: RTS
|
||||
|
||||
|
|
@ -0,0 +1,3 @@
|
|||
/* Atari 2600 Timer Bar Kernel */
|
||||
|
||||
|
||||
|
|
@ -0,0 +1,55 @@
|
|||
/* VCS Definitions Header */
|
||||
|
||||
//Boolean True and False
|
||||
#define TRUE = $FF
|
||||
#define FALSE = $0
|
||||
|
||||
//Set/Clear Various Registers
|
||||
//ENAM0, ENAM1, ENABL - Enable/Disable Missiles, Ball
|
||||
//REFP0, REFP01 - Enable/Disable Player Reflection
|
||||
//RESPMO, RESPM1 - Disable/Enable Missiles
|
||||
//VDELP0, VDELP1, VDELBL - Delay Players, Ball
|
||||
#define CLEAR = 0
|
||||
#define SET = $0B
|
||||
|
||||
//VBLANK Latches
|
||||
#define TRGL = $40 //Enable Joystick Trigger Latch
|
||||
#define DPDL = $80 //Dump Paddle Potentiometers
|
||||
|
||||
//NUSIZ0 and NUSIZ1 Missile Bit Masks
|
||||
#define MS1CLK = 0 //1 Clock Wide Missile
|
||||
#define MS2CLK = 1 //2 Clock Wide Missile
|
||||
#define MS4CLK = 2 //4 Clock Wide Missile
|
||||
#define MS8CLK = 3 //8 Clock Wide Missile
|
||||
|
||||
//NUSIZ0 and NUSIZ1 Player Bit Masks
|
||||
#define PL1SNG = 0 //Single Sized Player
|
||||
#define PL1DBL = 5 //Double Sized Player
|
||||
#define PL1QUD = 7 //Quadruple Sized Player
|
||||
#define PL2CLS = 1 //Two Close Copies of Player
|
||||
#define PL2MED = 2 //Two Medium Copies of Player
|
||||
#define PL2WID = 4 //Two Wide Copies of Player
|
||||
#define PL3CLS = 3 //Three Close Copies of Player
|
||||
#define PL3MED = 6 //Three Medium Copies of Player
|
||||
|
||||
//AUDC0 and AUDC1 Audio Control Registers
|
||||
#define D02PUR = $04 //Divide by 2, Pure Tone
|
||||
#define D06PUR = $0C //Divide by 6, Pure Tone
|
||||
#define D32PUR = $06 //Divide by 31, Pure Tone
|
||||
#define D93PUR = $0E //Divide by 93, Pure Tone
|
||||
#define D00PL4 = $01 //No Divide, 4 Bit Polynomial
|
||||
#define D00PL5 = $09 //No Divide, 5 Bit Polynomial
|
||||
#define D00PL9 = $08 //No Divide, 9 Bit Polynomial
|
||||
#define D15PL4 = $02 //Divide by 15 -> 4 Bit Polynomial
|
||||
#define PL5PL4 = $03 //5 Bit Polynomial -> 4 Bit Polynomial
|
||||
#define PL5D06 = $0F //5 Bit Polynomial -> Divide by 6
|
||||
#define PL4502 = $07 //6 Bit Polynomial -> Divide by 2
|
||||
|
||||
//SWCHB Console Switch Bit Masks
|
||||
#define P1DIFF = $80 //Player 1 Difficulty
|
||||
#define P0DIFF = $40 //Player 0 Difficulty
|
||||
#define CLRBW = $08 //Color/Black & White
|
||||
#define SELECT = $02 //Game Select
|
||||
#define RESET = $01 //Game Reset
|
||||
|
||||
|
||||
|
|
@ -0,0 +1,9 @@
|
|||
;vcsfoot.a02 - C02 Assembly Language Footer File for Atari 2600
|
||||
;Created by Curtis F Kaylor - June 18, 2017
|
||||
|
||||
ORG $FFF4 ;Control and Interrupt Registers
|
||||
DS 8 ;$FFF4-$FFF9 Bank Switch Registers
|
||||
DC.W START ;$FFFC Reset Vector
|
||||
DC.W IRQBRK ;$FFFE Interrupt Vector
|
||||
|
||||
|
||||
|
|
@ -0,0 +1,9 @@
|
|||
/* vcsfoot.h02 - C02 Footer File for Atari 2600 *
|
||||
* The last line of the program must be *
|
||||
* #include <vcsfoot.h> *
|
||||
* The following two labels must be present in the program *
|
||||
* irqbrk: subroutine to call when a BRK instruction is encountered *
|
||||
* start: program start on power up */
|
||||
|
||||
#pragma vartable //Write Variable Table
|
||||
|
||||
|
|
@ -0,0 +1,79 @@
|
|||
;vcshead.a02 - C02 Assembly Language Header file for Atari 2600
|
||||
;based on VCS.H Version 1.05, 13/November/2003
|
||||
;https://github.com/munsie/dasm/blob/master/machines/atari2600/vcs.h
|
||||
|
||||
;TIA Registers - Write
|
||||
VSYNC EQU $00 ;0000 00x0 Vertical Sync Set-Clear
|
||||
VBLANK EQU $01 ;xx00 00x0 Vertical Blank Set-Clear
|
||||
WSYNC EQU $02 ;---- ---- Wait for Horizontal Blank
|
||||
RSYNC EQU $03 ;---- ---- Reset Horizontal Sync Counter
|
||||
NUSIZ0 EQU $04 ;00xx 0xxx Number-Size player/missle 0
|
||||
NUSIZ1 EQU $05 ;00xx 0xxx Number-Size player/missle 1
|
||||
COLUP0 EQU $06 ;xxxx xxx0 Color-Luminance Player 0
|
||||
COLUP1 EQU $07 ;xxxx xxx0 Color-Luminance Player 1
|
||||
COLUPF EQU $08 ;xxxx xxx0 Color-Luminance Playfield
|
||||
COLUBK EQU $09 ;xxxx xxx0 Color-Luminance Background
|
||||
CTRLPF EQU $0A ;00xx 0xxx Control Playfield, Ball, Collisions
|
||||
REFP0 EQU $0B ;0000 x000 Reflection Player 0
|
||||
REFP1 EQU $0C ;0000 x000 Reflection Player 1
|
||||
PF0 EQU $0D ;xxxx 0000 Playfield Register Byte 0
|
||||
PF1 EQU $0E ;xxxx xxxx Playfield Register Byte 1
|
||||
PF2 EQU $0F ;xxxx xxxx Playfield Register Byte 2
|
||||
RESP0 EQU $10 ;---- ---- Reset Player 0
|
||||
RESP1 EQU $11 ;---- ---- Reset Player 1
|
||||
RESM0 EQU $12 ;---- ---- Reset Missle 0
|
||||
RESM1 EQU $13 ;---- ---- Reset Missle 1
|
||||
RESBL EQU $14 ;---- ---- Reset Ball
|
||||
AUDC0 EQU $15 ;0000 xxxx Audio Control 0
|
||||
AUDC1 EQU $16 ;0000 xxxx Audio Control 1
|
||||
AUDF0 EQU $17 ;000x xxxx Audio Frequency 0
|
||||
AUDF1 EQU $18 ;000x xxxx Audio Frequency 1
|
||||
AUDV0 EQU $19 ;0000 xxxx Audio Volume 0
|
||||
AUDV1 EQU $1A ;0000 xxxx Audio Volume 1
|
||||
GRP0 EQU $1B ;xxxx xxxx Graphics Register Player 0
|
||||
GRP1 EQU $1C ;xxxx xxxx Graphics Register Player 1
|
||||
ENAM0 EQU $1D ;0000 00x0 Graphics Enable Missle 0
|
||||
ENAM1 EQU $1E ;0000 00x0 Graphics Enable Missle 1
|
||||
ENABL EQU $1F ;0000 00x0 Graphics Enable Ball
|
||||
HMP0 EQU $20 ;xxxx 0000 Horizontal Motion Player 0
|
||||
HMP1 EQU $21 ;xxxx 0000 Horizontal Motion Player 1
|
||||
HMM0 EQU $22 ;xxxx 0000 Horizontal Motion Missle 0
|
||||
HMM1 EQU $23 ;xxxx 0000 Horizontal Motion Missle 1
|
||||
HMBL EQU $24 ;xxxx 0000 Horizontal Motion Ball
|
||||
VDELP0 EQU $25 ;0000 000x Vertical Delay Player 0
|
||||
VDELP1 EQU $26 ;0000 000x Vertical Delay Player 1
|
||||
VDELBL EQU $27 ;0000 000x Vertical Delay Ball
|
||||
RESMP0 EQU $28 ;0000 00x0 Reset Missle 0 to Player 0
|
||||
RESMP1 EQU $29 ;0000 00x0 Reset Missle 1 to Player 1
|
||||
HMOVE EQU $2A ;---- ---- Apply Horizontal Motion
|
||||
HMCLR EQU $2B ;---- ---- Clear Horizontal Move Registers
|
||||
CXCLR EQU $2C ;---- ---- Clear Collision Latches
|
||||
|
||||
;TIA Regisers - Read bit 7 bit 6
|
||||
CXM0P EQU $00 ;xx00 0000 Read Collision M0-P1 M0-P0
|
||||
CXM1P EQU $01 ;xx00 0000 M1-P0 M1-P1
|
||||
CXP0FB EQU $02 ;xx00 0000 P0-PF P0-BL
|
||||
CXP1FB EQU $03 ;xx00 0000 P1-PF P1-BL
|
||||
CXM0FB EQU $04 ;xx00 0000 M0-PF M0-BL
|
||||
CXM1FB EQU $05 ;xx00 0000 M1-PF M1-BL
|
||||
CXBLPF EQU $06 ;x000 0000 BL-PF
|
||||
CXPPMM EQU $07 ;xx00 0000 P0-P1 M0-M1
|
||||
INPT0 EQU $08 ;x000 0000 Read Pot Port 0
|
||||
INPT1 EQU $09 ;x000 0000 Read Pot Port 1
|
||||
INPT2 EQU $0A ;x000 0000 Read Pot Port 2
|
||||
INPT3 EQU $0B ;x000 0000 Read Pot Port 3
|
||||
INPT4 EQU $0C ;x000 0000 Read Input (Trigger) 0
|
||||
INPT5 EQU $0D ;x000 0000 Read Input (Trigger) 1
|
||||
|
||||
; RIOT Registers
|
||||
SWCHA EQU $280 ;Port A data register for joysticks:
|
||||
;Bits 4-7 for player 1. Bits 0-3 for player 2.
|
||||
SWACNT EQU $281 ;Port A data direction register (DDR)
|
||||
SWCHB EQU $282 ;Port B data (console switches)
|
||||
SWBCNT EQU $283 ;Port B DDR
|
||||
INTIM EQU $284 ;Timer output
|
||||
TIM1T EQU $294 ;set 1 clock interval
|
||||
TIM8T EQU $295 ;set 8 clock interval
|
||||
TIM64T EQU $296 ;set 64 clock interval
|
||||
T1024T EQU $297 ;set 1024 clock interval
|
||||
|
||||
|
|
@ -0,0 +1,80 @@
|
|||
//vcshead.h02 - C02 Header file for Atari 2600
|
||||
|
||||
//TIA Registers - Write
|
||||
char VSYNC; //Vertical Sync
|
||||
char VBLANK; //Vertical Blank
|
||||
char WSYNC; //Wait for Horizontal Blank
|
||||
char RSYNC; //Reset Horizontal Sync Counter
|
||||
char NUSIZ0; //Number-Size Player/Missile 0
|
||||
char NUSIZ1; //Number-Size Player/Missile 1
|
||||
char COLUP0; //Color-Luminance Player 0
|
||||
char COLUP1; //Color-Luminance Player 1
|
||||
char COLUPF; //Color-Luminance Playfield
|
||||
char COLUBK; //Color-Luminance Background
|
||||
char CTRLPF; //Control Playfield, Ball, Collisions
|
||||
char REFP0; //Reflection Player 0
|
||||
char REFP1; //Reflection Player 1
|
||||
char PF0; //Playfield Register Byte 0
|
||||
char PF1; //Playfield Register Byte 1
|
||||
char PF2; //Playfield Register Byte 2
|
||||
char RESP0; //Reset Player 0
|
||||
char RESP1; //Reset Player 1
|
||||
char RESM0; //Reset Missle 0
|
||||
char RESM1; //Reset Missle 1
|
||||
char RESBL; //Reset Ball
|
||||
char AUDC0; //Audio Control 0
|
||||
char AUDC1; //Audio Control 1
|
||||
char AUDF0; //Audio Frequency 0
|
||||
char AUDF1; //Audio Frequency 1
|
||||
char AUDV0; //Audio Volume 0
|
||||
char AUDV1; //Audio Volume 1
|
||||
char GRP0; //Graphics Register Player 0
|
||||
char GRP1; //Graphics Register Player 1
|
||||
char ENAM0; //0000 00x0 Graphics Enable Missle 0
|
||||
char ENAM1; //0000 00x0 Graphics Enable Missle 1
|
||||
char ENABL; //0000 00x0 Graphics Enable Ball
|
||||
char HMP0; //Horizontal Motion Player 0
|
||||
char HMP1; //Horizontal Motion Player 1
|
||||
char HMM0; //Horizontal Motion Missle 0
|
||||
char HMM1; //Horizontal Motion Missle 1
|
||||
char HMBL; //Horizontal Motion Ball
|
||||
char VDELP0; //0000 000x Vertical Delay Player 0
|
||||
char VDELP1; //0000 000x Vertical Delay Player 1
|
||||
char VDELBL; //0000 000x Vertical Delay Ball
|
||||
char RESMP0; //0000 00x0 Reset Missle 0 to Player 0
|
||||
char RESMP1; //0000 00x0 Reset Missle 1 to Player 1
|
||||
char HMOVE; //Apply Horizontal Motion
|
||||
char HMCLR; //Clear Horizontal Move Registers
|
||||
char CXCLR; //Clear Collision Latches
|
||||
|
||||
//TIA Registers - Read bit 7 bit 6
|
||||
char CXM0P; //Read Collision M0-P1 M0-P0
|
||||
char CXM1P; // M1-P0 M1-P1
|
||||
char CXP0FB; // P0-PF P0-BL
|
||||
char CXP1FB; // P1-PF P1-BL
|
||||
char CXM0FB; // M0-PF M0-BL
|
||||
char CXM1FB; // M1-PF M1-BL
|
||||
char CXBLPF; // BL-PF
|
||||
char CXPPMM; // P0-P1 M0-M1
|
||||
char INPT0; //Read Pot Port 0
|
||||
char INPT1; //Read Pot Port 1
|
||||
char INPT2; //Read Pot Port 2
|
||||
|
||||
char INPT3; //Read Pot Port 3
|
||||
char INPT4; //Read Input (Trigger) 0
|
||||
char INPT5; //Read Input (Trigger) 1
|
||||
|
||||
//RIOT Registers
|
||||
char SWCHA; //Port A data register for joysticks:
|
||||
//Bits 4-7 for Player 1. Bits 0-3 for Player 2.
|
||||
char SWACNT; //Port A data direction register (DDR)
|
||||
char SWCHB; //Port B data (console switches)
|
||||
char SWBCNT; //Port B DDR
|
||||
char INTIM; //Timer output
|
||||
char TIM1T; //set 1 clock interval
|
||||
char TIM8T; //set 8 clock interval
|
||||
char TIM64T; //set 64 clock interval
|
||||
char T1024T; //set 1024 clock interval
|
||||
|
||||
#pragma zeropage $80 //Zero Page RAM Base Address
|
||||
|
||||
|
|
@ -0,0 +1,19 @@
|
|||
;Atari 2600 Initialization Code - C02 Assembly Language File
|
||||
; From CLEAN_START macro by Andrew Davie
|
||||
; Standardised start-up code, clears stack, all TIA registers and RAM to 0
|
||||
; Sets stack pointer to $FF, and all registers to 0
|
||||
; Sets decimal mode off, sets interrupt flag (kind of un-necessary)
|
||||
; Use as very first section of code on boot (ie: at reset)
|
||||
; Code written to minimise total ROM usage - uses weird 6502 knowledge :)
|
||||
|
||||
START: SEI
|
||||
CLD
|
||||
LDX #0
|
||||
TXA
|
||||
TAY
|
||||
STARTC: DEX
|
||||
TXS
|
||||
PHA
|
||||
BNE STARTC
|
||||
JMP MAIN
|
||||
|
||||
|
|
@ -0,0 +1,7 @@
|
|||
/* vcsinit.h02 - Initialize Atari 2600 *
|
||||
* Usage: *
|
||||
* #include <vcsfoot.h> *
|
||||
* Contains the start label required by vcsfoot.h02 *
|
||||
* Program must contain the following label *
|
||||
* main: program code */
|
||||
|
||||
|
|
@ -0,0 +1,37 @@
|
|||
;C02 VCS Library - Assembly Language Subroutines
|
||||
|
||||
;addbcd(addend, &varble) - Add Number to BCD variable
|
||||
;adcbcd(addend, &varble) - Add Number w/Carry to BCD variable
|
||||
;Args: A = Number to Add
|
||||
; X,Y = Pointer to Variable to Add To
|
||||
;Sets: TEMP0,TEMP1 = Pointer to Color Table
|
||||
;Affects: A,Y,C,N,Z
|
||||
;Updates: Variable Pointed to by X,Y
|
||||
;Returns: A = Result of Addition
|
||||
ADDBCD: CLC ;Clear Carry - Regular Add
|
||||
ADCBCD: STX TEMP0 ;Save Pointer to Variable
|
||||
STY TEMP1
|
||||
LDY #0
|
||||
SED ;Set Decimal Mode
|
||||
ADC (TEMP0),Y ;Add Accumulator to Variable
|
||||
STA (TEMP0),Y ;Store Result in Variable
|
||||
CLD ;Clear Decimal Mode
|
||||
RTS ;Return
|
||||
|
||||
;posobj(hrzpos, object) - Position Object
|
||||
;Args: A = Horizontal Position
|
||||
; Y = Object (0=Player0, 1=Player1, 2=Missile0, 3=Missle1, 4=Ball)
|
||||
;Affects: A,C,Z
|
||||
POSOBJ: SEC
|
||||
STA WSYNC ;Wait for Beginning of Scanline
|
||||
POSOBL: SBC #15 ;2 2 - each time thru this loop takes 5 cycles, which is
|
||||
BCS POSOBL ;2 4 - the same amount of time it takes to draw 15 pixels
|
||||
EOR #7 ;2 6 - The EOR & ASL statements convert the remainder
|
||||
ASL ;2 8 - of position/15 to the value needed to fine tune
|
||||
ASL ;2 10 - the X position
|
||||
ASL ;2 12
|
||||
ASL ;2 14
|
||||
STA.WY HMP0,Y ;5 19 - store fine tuning of X
|
||||
STA RESP0,Y ;4 23 - set coarse X position of object
|
||||
RTS ;6 29
|
||||
|
||||
|
|
@ -0,0 +1,6 @@
|
|||
/* Atari 2600 Library Functions for C02 */
|
||||
|
||||
char adcbcd(); //BCD Add w/Carry to Variable
|
||||
char addbcd(); //BCD Add to Variable
|
||||
void posobj(); //Position Object
|
||||
|
||||
|
|
@ -0,0 +1,34 @@
|
|||
vcslib - Atari 2600 Library Functions for C02
|
||||
|
||||
This library contains commonly used functions for the Atari VCS.
|
||||
|
||||
res = adcbcd(num, &var); Adds value num plus carry to variable var
|
||||
using BCD arithmetic.
|
||||
|
||||
Used to update multi-byte BCD numbers, such
|
||||
as scores with more than two digits.
|
||||
|
||||
Returns the updated contents of var. Can
|
||||
be called as a void function if the result
|
||||
is not needed.
|
||||
|
||||
res = addbcd(num, &var); Adds value num to variable var using BCD
|
||||
arithmetic.
|
||||
|
||||
Used to update BCD numbers, such as two
|
||||
digit scores.
|
||||
|
||||
Returns the updated contents of var. Can
|
||||
be called as a void function if the result
|
||||
is not needed.
|
||||
|
||||
posobj(hrz, obj); Sets horizontal position of object obj to
|
||||
hrz.
|
||||
|
||||
Argument obj may be any of the following:
|
||||
0 = Player 0
|
||||
1 = Player 1
|
||||
2 = Missile 0
|
||||
3 = Missile 1
|
||||
4 = Ball
|
||||
|
||||
|
|
@ -0,0 +1,3 @@
|
|||
;vcsrtns.a02 - Atari 2600 Common Assembly Language Routines for C02
|
||||
|
||||
|
||||
|
|
@ -0,0 +1,8 @@
|
|||
/* vcsrtns.h02 - Common Atari 2600 Function for C02 *
|
||||
* Usage: *
|
||||
* #include <vcsrtns.h02> *
|
||||
* Requires the following zero page variables: *
|
||||
* TEMP0 *
|
||||
* */
|
||||
|
||||
|
||||
|
|
@ -0,0 +1,71 @@
|
|||
;Atart 2600 Program Stub - C02 Assembly Language File
|
||||
|
||||
;Preset Total Number of Kernal Lines
|
||||
KNLLNS SET 192 ;192 Lines on NTSC Television
|
||||
|
||||
;Variables Used By Other Libraries
|
||||
TEMP0 EQU $E0 ;Temporary Storage
|
||||
TEMP1 EQU $E1
|
||||
TEMP2 EQU $E2
|
||||
TEMP3 EQU $E3
|
||||
|
||||
;Initialization Code
|
||||
; From CLEAN_START macro by Andrew Davie
|
||||
; Standardised STArt-up code, clears STAck, all TIA registers and RAM to 0
|
||||
; Sets STAck pointer to $FF, and all registers to 0
|
||||
; Sets decimal mode off, sets interrupt flag (kind of un-necessary)
|
||||
; Use as very first section of code on boot (ie: at reset)
|
||||
; Code written to minimise total ROM usage - uses weird 6502 knowledge :)
|
||||
START: SEI
|
||||
CLD
|
||||
LDX #0
|
||||
TXA
|
||||
TAY
|
||||
STARTC: DEX
|
||||
TXS
|
||||
PHA
|
||||
BNE STARTC
|
||||
|
||||
JSR SETUP ;Execute Setup Code
|
||||
|
||||
MAIN: LDA #2 ;Vertical Sync On Bit Mask
|
||||
LDX #49 ;41 scanlines * 76 cycles / 64
|
||||
STA WSYNC ;Wait for SYNC (halts CPU until end of scanline)
|
||||
STA VSYNC ;Turn On Vertical Sync
|
||||
STX TIM64T ;Set timer to go off in 41 scanlines
|
||||
STA WSYNC ;First Scanline of VSYNC
|
||||
STA WSYNC ;Second Scanline of VSYNC
|
||||
LDA #0 ;Vertical Sync Off Bit Mask
|
||||
STA WSYNC ;Third Scanline of VSYNC
|
||||
STA VSYNC ;Turn Off Vertical Sync
|
||||
JSR VRTBLK ;Execute Vertical Blank Code
|
||||
STA WSYNC ;Wait For Horizontal Sync
|
||||
STA HMOVE ;Execute Horizontal Moves
|
||||
JSR CLRHMX ;Clear Horizontal Move Registers
|
||||
WTVBLK: STA WSYNC ;Wait for End of Vertical Blank
|
||||
LDA INTIM ;Check Timer
|
||||
BNE WTVBLK ;Loop If Not Zero
|
||||
STA VBLANK ;Turn off Vertical Blank
|
||||
JSR KERNEL ;Execute Kernel Code
|
||||
STA WSYNC ;Wait for End of Scanline
|
||||
LDA #2 ;Vertical Blank On Bit Mask
|
||||
STA VBLANK ;Turn on Vertical Blank
|
||||
LDA #32 ;27 scanlines * 76 cycles / 64
|
||||
STA TIM64T ;Set Timer for 27 scanlines
|
||||
JSR OVRSCN ;Execute Overscan Code
|
||||
WTOSCN: STA WSYNC ;Wait for End of Overscan
|
||||
LDA INTIM ;Check Time
|
||||
BNE WTOSCN ;Loop If Not Zero
|
||||
BEQ MAIN ;Loop Back to Vertical Sync
|
||||
|
||||
IRQBRK: RTI ;Catch 6502 Break Instructions
|
||||
|
||||
CLRHMR: NOP ; 2 8 (+6 for calling JSR)
|
||||
JSR CLRHMX ;12 20
|
||||
LDA #0 ; 2 22 - Clear Horizontal Move Registers
|
||||
LDX #4 ; 2 24
|
||||
CLRHML STA HMP0,X ; - Safe to Clear 24 Cycles after HMOVE
|
||||
DEX
|
||||
BPL CLRHML
|
||||
CLRHMX: RTS
|
||||
|
||||
|
|
@ -0,0 +1,10 @@
|
|||
/* vcsstub.h02 - Atari 2600 Program Stub *
|
||||
* Usage: *
|
||||
* #include <vcsstub.h> *
|
||||
* Contains the start label required by vcsfoot.h02 *
|
||||
* Program must contain the following functions *
|
||||
* setup() - Program Startup Code
|
||||
* vrtblk() - Code to Execute During Vertical Blank *
|
||||
* kernel() - Kernel Code - Draws Screen *
|
||||
* ovrscn() - Code to Execute During Overscan */
|
||||
|
||||
Loading…
Reference in New Issue