Improved Atari 2600 example programs
Add the color test program as a sample program. Also update the hi_stella example so that it runs properly when run in a Harmony cartridge.
This commit is contained in:
Michael Martin
parent
c3d48da59d
commit
778fbf7e2c
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@ -1,7 +0,0 @@
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"Hi Stella" is a simple "Hello World" program for the "Stella" chip,
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more famously known as the Atari 2600. Simply running
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ophis hi_stella.oph
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should produce hi_stella.bin, a 256-byte file that prints "HI" on
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the screen with some rolling color bars.
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@ -0,0 +1,13 @@
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"Hi Stella" is a simple "Hello World" program for the "Stella" chip,
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more famously known as the Atari 2600. Simply running
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ophis hi_stella.oph
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should produce hi_stella.bin, a 256-byte file that prints "HI" on
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the screen with some rolling color bars.
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A more sophisticated program is colortest, which lets the user
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explore the 128 colors provided by the system. Use up and down
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to move the color value by 2, and left and right to move it
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by 16. (The lowest bit in the color value byte is ignored, for
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a total of 128 colors available.)
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@ -0,0 +1,391 @@
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;;; ---------- COLOR TEST ----------
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;;; Michael Martin, 2014
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;;;
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;;; This is a sample program for the Atari 2600 VCS that lets you
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;;; explore the 128-color palette the system provides. This is
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;;; presented mainly as a more sophisticated example program to
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;;; supplement "hi_stella".
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;;;
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;;; It makes use of every graphical element but the Ball, and also
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;;; makes use of multicolor asymmetric playfields.
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.require "../../platform/stella.oph"
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.outfile "colortest.bin"
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.data
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.org $0080
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.space startcol 1 ; Starting color for the striped playfield
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.space subrow 1 ; Counting lines per "tall pixel"
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.space curcol 1 ; The color number we are focusing on at the moment
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.space high_nybble 2 ; Pointer to graphic data for 16s hexit
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.space low_nybble 2 ; Pointer to graphic data for ones hexit
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.space input_allowed 1 ; Flag for whether or not to ignore input.
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.text
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;; Start at $f800 - 2KB ROMs are the smallest size available.
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.org $f800
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reset: `clean'start
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;; We offer 1c as the initial color. It's a nice yellow shade.
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lda #$1c
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sta curcol
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frame: `vertical'sync ; Beginning of the frame. Set up the timer
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lda #43 ; to count out the length of VBLANK while
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sta TIM64T ; we do the processing for the display.
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;; Place the player and missile graphics appropriately. We
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;; count cycles and write the missile and player reset registers
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;; at the closest times we can manage. Due to the way the TIA
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;; timing works, the formula for the pixel they will show up at
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;; is N*3-55+P, where N is the number of cycles from the end of
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;; the latest STA WSYNC and the end of the STA RES* instruction,
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;; and P is 1 for player sprites and 0 for missiles and the ball.
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;;
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;; The line after that we can strobe HMOVE to adjust them the
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;; rest of the way into place.
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;;
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;; We will be using the missiles to draw the left and right
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;; sides of a largish square and the player sprites to display a
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;; byte value (the current color) as two hex digits (one per
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;; player). All the rest of our graphics will be done via the
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;; playfield registers.
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;;
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;; The missile graphics are being targeted to pixels 40 and 116
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;; and will be 4 pixels wide each. The player graphics will be
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;; 8 pixels wide and are targeting pixels 72 and 80.
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sta WSYNC
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sta WSYNC ; = 0
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ldy #$06 ; +2 = 2
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* dey ; +2 = 4- 9-14-19-24-29
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bne - ; +3 = 7-12-17-22-27-31
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sta RESM0 ; +3 = 34 (31*3-55 = 38. Needs to move 2 pixels right.)
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lda #$E0 ; +2 = 36
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sta HMCLR ; +3 = 39 - reset the fine-move registers
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sta HMM0 ; +3 = 42 - set M0 to move 2 right
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sta RESP0 ; +3 = 45 (42*3-54 = 72. Placed perfectly.)
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sta RESP1 ; +3 = 48 (45*3-54 = 81. Needs to move 1 pixel left.)
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lda #$10 ; +2 = 50
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sta HMP1 ; +3 = 53 - and set P1 to move 1 left.
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nop ; +2 = 55
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nop ; +2 = 57
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sta RESM1 ; +3 = 60 (57*3-55 = 116. Placed perfectly.)
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sta WSYNC
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sta HMOVE ; Next scanline, execute the fine moves.
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lda #$20
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sta NUSIZ0 ; Quad-size missiles, single copy of single player
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sta NUSIZ1 ; M1 and P1 are the same
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;; Read the input
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lda #$00
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sta SWACNT
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lda SWCHA
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bit input_allowed
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bmi true_input_read
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;; Wait for neutral stick so we can re-enable input.
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and #$f0
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cmp #$f0
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bne input_done
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;; Bits are set if the direction isn't active, so we only get
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;; here if the stick was neutral. this also means the accumulator
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;; has #$f0 in it now, which means we can store it directly and
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;; the BIT/BMI above will start succeeding next frame.
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sta input_allowed
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beq input_done
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true_input_read:
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;; Now we rotate it through the carry bit to see what
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;; direction was pushed. We advance the color 2 or 16 at a time,
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;; depending. (The least significant bit in the color register is
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;; the one ignored, so we are not missing anything here.)
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ror ; Skip P2 input
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ror
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ror
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ror
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ror ; Carry clear if up
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bcs +
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inc curcol ; If up, increase color by 2
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inc curcol
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jmp input_found
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* ror ; Carry clear if down
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bcs +
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dec curcol ; If down, decrease color by 2
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dec curcol
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jmp input_found
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* ror ; Carry clear if left
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bcs +
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lda curcol
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sec
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sbc #$10 ; Left decreases color by 16
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sta curcol
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jmp input_found
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* ror ; Carry clear if right
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bcs input_done
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lda curcol
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adc #$10 ; Right increases color by 16
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sta curcol
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input_found:
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lda #$00
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sta input_allowed
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input_done:
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;; Clear the playfield while we wait, and make it asymmetric
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lda #$00
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sta PF0
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sta PF1
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sta PF2
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sta CTRLPF
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;; alter playfield color so we get a rotating effect
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dec startcol
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;; prepare numeric sprite values
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lda curcol
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lsr
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lsr
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lsr
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lsr
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tay
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lda digits_low, y
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sta high_nybble
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lda curcol
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and #$0f
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tay
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lda digits_low, y
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sta low_nybble
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lda #$ff
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sta low_nybble+1
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sta high_nybble+1
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;; Wait for VBLANK to finish, then turn off the VBLANK signal.
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* lda INTIM
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bne -
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sta WSYNC
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sta VBLANK
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;; Display kernel.
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;; Top blank: 4 lines
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ldx #4
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stx subrow
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* sta WSYNC
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dex
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bne -
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;; Header graphics: 20 lines
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ldy #5
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ldx startcol
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header_loop:
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sta WSYNC
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stx COLUPF ; +3 = 3
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lda pf0_left-1,y ; +4 = 7
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sta PF0 ; +3 = 10
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lda pf1_left-1,y ; +4 = 14
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sta PF1 ; +3 = 17
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lda pf2_left-1,y ; +4 = 21
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sta PF2 ; +3 = 24
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cmp $80 ; +3 = 27 (3-cycle no-op)
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lda pf0_right-1,y ; +4 = 31
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sta PF0 ; +3 = 34
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lda pf1_right-1,y ; +4 = 38
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sta PF1 ; +3 = 41
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lda pf2_right-1,y ; +4 = 45
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sta PF2 ; +3 = 48 ** MUST STORE PF2 2ND TIME ON EXACTLY CYCLE 48 **
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inx ; +2 = 50
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inx ; +2 = 52
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dec subrow ; +5 = 57
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bne header_loop ; +2 = 59
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dey ; +2 = 61
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beq header_done ; +2 = 63
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lda #4 ; +2 = 65
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sta subrow ; +3 = 68
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bne header_loop ; +3 = 71
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;; We've cut it very fine here! We only have 76 cycles per
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;; scanline and we use nearly all of them.
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header_done:
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;; Ruled split between title and data (8 lines)
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ldy #$00 ; Clear playfield now that we're done (+2 = 72)
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ldx #$0c ; Default status color is light grey (+2 = 74)
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sta WSYNC ; Rest of previous line
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sty PF0
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sty PF1
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sty PF2
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stx COLUPF
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stx COLUP0
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stx COLUP1
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dey
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ldx #$f0
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sta WSYNC
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sta WSYNC
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sta WSYNC
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stx PF0 ; Fill playfield completely
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sty PF1
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sty PF2
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ldy #$01
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sty CTRLPF ; Symmetric PF
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sta WSYNC
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sta WSYNC
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sta WSYNC
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sta WSYNC
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dey
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sty PF0 ; Clear playfield again
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sty PF1
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sty PF2
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ldy #$08 ; 32 lines (for letters; 8, 16, 8)
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* sta WSYNC
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dey
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bne -
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ldy #$06
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* lda (high_nybble), y
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sta GRP0
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lda (low_nybble), y
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sta GRP1
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sta WSYNC
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sta WSYNC
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dey
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bpl -
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iny
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sty GRP0
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sty GRP1
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ldy #$0A
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* sta WSYNC
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dey
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bne -
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;; Top border (12 lines)
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lda #$03
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sta PF1
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lda #$ff
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sta PF2
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sta WSYNC
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sta WSYNC
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sta WSYNC
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sta WSYNC
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sta WSYNC
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sta WSYNC
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ldx #$00
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stx PF1
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stx PF2
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ldx #$02 ; Turn on walls (the missiles)
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stx ENAM0
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stx ENAM1
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sta WSYNC
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sta WSYNC
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sta WSYNC
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sta WSYNC
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sta WSYNC
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sta WSYNC
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sta PF2
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lda curcol
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sta COLUPF
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;; Color blob (96 lines)
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ldx #96
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* sta WSYNC
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dex
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bne -
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;; Bottom border (12 lines)
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stx PF2
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lda #$0c
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sta COLUPF
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sta WSYNC
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sta WSYNC
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sta WSYNC
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sta WSYNC
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sta WSYNC
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sta WSYNC
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stx ENAM0 ; Turn off walls (the missles)
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stx ENAM1
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lda #$03
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sta PF1
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lda #$ff
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sta PF2
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sta WSYNC
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sta WSYNC
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sta WSYNC
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sta WSYNC
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sta WSYNC
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sta WSYNC
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stx PF1
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stx PF2
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ldx #$08
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* sta WSYNC
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dex
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bne -
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; Turn on VBLANK, do 30 lines of Overscan
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lda #$02
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sta VBLANK
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ldy #30
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* sta WSYNC
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dey
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bne -
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jmp frame ; And the frame is done, back to VSYNC.
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;;; Graphical data. Notice that we have to start not on a page
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;;; boundary, but with all graphics in each group on one page.
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.advance $FF01
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pf0_left:
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.byte $e0,$20,$20,$20,$e0
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pf1_left:
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.byte $77,$54,$54,$54,$74
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pf2_left:
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.byte $ae,$6a,$ea,$aa,$ee
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pf0_right:
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.byte $00,$00,$00,$00,$00
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pf1_right:
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.byte $4e,$48,$4c,$48,$ee
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pf2_right:
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.byte $27,$24,$27,$21,$77
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;; We don't need a digits_high. It's always $FF!
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digits_low:
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.byte <digit_0, <digit_1, <digit_2, <digit_3
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.byte <digit_4, <digit_5, <digit_6, <digit_7
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.byte <digit_8, <digit_9, <digit_a, <digit_b
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.byte <digit_c, <digit_d, <digit_e, <digit_f
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digit_0:
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.byte $3c,$66,$66,$76,$6e,$66,$3c
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digit_1:
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.byte $7e,$18,$18,$18,$38,$18,$18
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digit_2:
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.byte $7e,$60,$30,$0c,$06,$66,$3c
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digit_3:
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.byte $3c,$66,$06,$1c,$06,$66,$3c
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digit_4:
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.byte $06,$06,$7f,$66,$1e,$0e,$06
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digit_5:
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.byte $3c,$66,$06,$06,$7c,$60,$7e
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digit_6:
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.byte $3c,$66,$66,$7c,$60,$66,$3c
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digit_7:
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.byte $18,$18,$18,$18,$0c,$66,$7e
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digit_8:
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.byte $3c,$66,$66,$3c,$66,$66,$3c
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digit_9:
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.byte $3c,$66,$06,$3e,$66,$66,$3c
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digit_a:
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.byte $66,$66,$66,$7e,$66,$3c,$18
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digit_b:
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.byte $7c,$66,$66,$7c,$66,$66,$7c
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digit_c:
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.byte $3c,$66,$60,$60,$60,$66,$3c
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digit_d:
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.byte $78,$6c,$66,$66,$66,$6c,$78
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digit_e:
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.byte $7e,$60,$60,$78,$60,$60,$7e
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digit_f:
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.byte $60,$60,$60,$78,$60,$60,$7e
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;;; Interrupt vectors.
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.advance $FFFA
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.word reset, reset, reset
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@ -9,37 +9,42 @@
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.space counter 1
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.text
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.org $FF00
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.org $F800
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reset: `clean'start
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; Initialize the player sprites.
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; We're going to use quad-sized players for our
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; letters. With 160 color clocks, and letters
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; twenty clocks wide, and a 68 color clock HBLANK,
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; we want to place the two letters at color clock
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; 68+80-20-2 = 126 and 68+80+2 = 150. Those
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; translate to cycle counts 42 and 50.
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; letters, and each one is 5 notional pixels wide.
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; When we write RESP*, the start cycle after WSYNC
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; determines the pixel it appears at with the
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; formula 3N - 54 (minimum 1). Cycles 36 and 44
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; get us close. We end up 4 pixels too far left.
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; While we wait, we set up our sprites to be
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; quad-sized and initialize the independent
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; color-counters for each sprite.
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sta WSYNC ; 3
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lda #$07 ; 5
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sta NUSIZ0 ; 7
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sta NUSIZ1 ; 10
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lda #$20 ; 13
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ldy #5 ; 15
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sta WSYNC
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lda #$07 ; +2= 2
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sta NUSIZ0 ; +3= 5
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sta NUSIZ1 ; +3= 8
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lda #$20 ; +2=10
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ldy #5 ; +2=12
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* dey
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bne - ; 20-25-30-35-39
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sta RESP0 ; 42 - color clock 126
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sta col'0 ; 45
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eor #$80 ; 47
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sta RESP1 ; 50 - color clock 150
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bne - ; 17-22-27-32-36
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sta RESP0 ; +3=39 (P0 at pixel 54)
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sta col'0 ; +3=42
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eor #$80 ; +2=44
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sta RESP1 ; (P1 at pixel 78)
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sta col'1
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sta temp
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lda #$C0 ; HMOVE us 4 right
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sta HMP0
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sta HMP1
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sta WSYNC
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sta HMOVE
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frame: `vertical'sync
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lda #43
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@ -117,7 +122,7 @@ frame: `vertical'sync
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dey ; loop.
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bne -
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; Clear out the player graphics,,,
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; Clear out the player graphics...
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lda #$00
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sta GRP0
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sta GRP1
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@ -86,9 +86,14 @@ Section "Ophis" SEC01
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File "..\..\examples\structuredemo.oph"
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File "..\..\examples\fibonacci.oph"
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File "..\..\examples\kinematics.oph"
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SetOutPath "$INSTDIR\examples\hi_stella"
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File "..\..\examples\hi_stella\hi_stella.oph"
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File "..\..\examples\hi_stella\README.txt"
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# Remove the older copies of hi_stella if needed
|
||||
Delete "$INSTDIR\examples\hi_stella\hi_stella.oph"
|
||||
Delete "$INSTDIR\examples\hi_stella\README.txt"
|
||||
RMDir "$INSTDIR\examples\hi_stella"
|
||||
SetOutPath "$INSTDIR\examples\stella"
|
||||
File "..\..\examples\stella\hi_stella.oph"
|
||||
File "..\..\examples\stella\colortest.oph"
|
||||
File "..\..\examples\stella\README.txt"
|
||||
SetOutPath "$INSTDIR\examples\hello_nes"
|
||||
File "..\..\examples\hello_nes\hello_prg.oph"
|
||||
File "..\..\examples\hello_nes\hello_chr.oph"
|
||||
|
|
@ -159,8 +164,9 @@ Section Uninstall
|
|||
Delete "$INSTDIR\ophis.exe"
|
||||
Delete "$INSTDIR\ophismanual.pdf"
|
||||
Delete "$INSTDIR\README.txt"
|
||||
Delete "$INSTDIR\examples\hi_stella\hi_stella.oph"
|
||||
Delete "$INSTDIR\examples\hi_stella\README.txt"
|
||||
Delete "$INSTDIR\examples\stella\hi_stella.oph"
|
||||
Delete "$INSTDIR\examples\stella\colortest.oph"
|
||||
Delete "$INSTDIR\examples\stella\README.txt"
|
||||
Delete "$INSTDIR\examples\hello_nes\hello_prg.oph"
|
||||
Delete "$INSTDIR\examples\hello_nes\hello_chr.oph"
|
||||
Delete "$INSTDIR\examples\hello_nes\hello_ines.oph"
|
||||
|
|
@ -180,7 +186,7 @@ Section Uninstall
|
|||
Delete "$STARTMENU\Manual.lnk"
|
||||
|
||||
RMDir "$SMPROGRAMS\$ICONS_GROUP"
|
||||
RMDir "$INSTDIR\examples\hi_stella"
|
||||
RMDir "$INSTDIR\examples\stella"
|
||||
RMDir "$INSTDIR\examples\hello_nes"
|
||||
RMDir "$INSTDIR\examples"
|
||||
RMDir "$INSTDIR\platform"
|
||||
|
|
|
|||
Loading…
Reference in New Issue