starbot: so close

graphics/gr/starfield/Makefile

@@ -12,13 +12,16 @@ all:	starfield.dsk
 $(DOS33):	
 	cd ../../../utils/dos33fs-utils && make
 
-starfield.dsk:	$(DOS33) HELLO STARFIELD_DEMO STARFIELD_1K STARFIELD.BAS STARSMALL
+starfield.dsk:	$(DOS33) HELLO STARFIELD_DEMO STARFIELD_1K STARFIELD.BAS \
+	STARSMALL STARBOT STARBOT_LOOKUP
 	cp $(EMPTY_DISK)/empty.dsk starfield.dsk
 	$(DOS33) -y starfield.dsk SAVE A HELLO
 	$(DOS33) -y starfield.dsk SAVE A STARFIELD.BAS
 	$(DOS33) -y starfield.dsk BSAVE -a 0x1000 STARFIELD_DEMO
 	$(DOS33) -y starfield.dsk BSAVE -a 0x1000 STARFIELD_1K
 	$(DOS33) -y starfield.dsk BSAVE -a 0xc00 STARSMALL
+	$(DOS33) -y starfield.dsk BSAVE -a 0xc00 STARBOT_LOOKUP
+	$(DOS33) -y starfield.dsk BSAVE -a 0xc00 STARBOT
 
 ###
 
@@ -63,6 +66,22 @@ STARSMALL:   starsmall.o
 starsmall.o: starsmall.s
 	ca65 -o starsmall.o starsmall.s -l starsmall.lst
 
+###
+
+STARBOT:   starbot.o
+	ld65 -o STARBOT starbot.o -C $(LINKERSCRIPTS)/apple2_c00.inc
+
+starbot.o: starbot.s
+	ca65 -o starbot.o starbot.s -l starbot.lst
+
+###
+
+STARBOT_LOOKUP:   starbot_lookup.o
+	ld65 -o STARBOT_LOOKUP starbot_lookup.o -C $(LINKERSCRIPTS)/apple2_c00.inc
+
+starbot_lookup.o: starbot_lookup.s
+	ca65 -o starbot_lookup.o starbot_lookup.s -l starbot_lookup.lst
+
 
 ###
 

graphics/gr/starfield/starbot.s

@@ -11,9 +11,14 @@
 ; 170 bytes - can do sty zp,x
 ; 163 bytes - lose the cool HGR intro
 ; 161 bytes - re-arrange RNG location
+; 158 bytes - ra-arrange a lot to remove need for XX
+; 133 bytes -- undo opt, no lookup table, just raw divide
+; 145 bytes -- init stars at beginning, so don't initially run bacward if Z=FF
+; 135 bytes -- optimize divide some more
 
 COLOR		= $30
 
+NEGATIVE	= $F9
 QUOTIENT	= $FA
 DIVISOR		= $FB
 DIVIDEND	= $FC
@@ -21,11 +26,12 @@ XX		= $FD
 YY		= $FE
 FRAME		= $FF
 
-oldx		= $80
+star_z		= $60
-oldy		= $90
+oldx		= $70
-star_x		= $A0
+oldy		= $80
-star_y		= $B0
+star_x		= $90
-star_z		= $C0
+star_y		= $A0
+
 
 ;oldx		= $1000
 ;oldy		= $1040
@@ -39,6 +45,8 @@ LORES		= $C056		; Enable LORES graphics
 HGR2		= $F3D8
 HGR		= $F3E2
 PLOT		= $F800		; PLOT AT Y,A (A colors output, Y preserved)
+NEXTCOL		= $F85F
+SETCOL		= $F864		; COLOR=A
 SETGR		= $FB40
 WAIT		= $FCA8		; delay 1/2(26+27A+5A^2) us
 
@@ -46,59 +54,7 @@ small_starfield:
 
 	;0GR:DIMV(64,48):FORZ=1TO48:FORX=0TO64:V(X,Z)=(X*4-128)/Z+20:NEXTX,Z
 
-	jsr	SETGR
+	jsr	SETGR		; A is D0 after?
-
-	; init the X/Z tables
-
-	ldy	#63	; Y==z	 for(z=1;z<64;z++) {
-xloop:
-	ldx	#0	; X==x
-zloop:
-	lda	#$ff
-	sta	QUOTIENT
-;	stx	DIVIDEND
-	sty	DIVISOR
-	txa		; DIVIDEND
-div_loop:
-	inc	QUOTIENT
-	sec
-;	lda	DIVIDEND
-	sbc	DIVISOR
-;	sta	DIVIDEND
-	bpl	div_loop
-
-	; write out quotient
-
-	lda	QUOTIENT
-	pha
-	clc
-	adc	#20
-to_smc:
-	sta	$5F80,X
-
-	inx
-	bpl	zloop	; loop until 128
-
-
-	; reverse and write out negative parts
-
-	ldx	#0
-negative_loop:
-	pla
-	eor	#$ff
-	sec
-	adc	#20
-to2_smc:
-	sta	$5F00,X
-	inx
-	bpl	negative_loop
-
-	dec	to_smc+2
-	dec	to2_smc+2
-
-	dey
-	bne	xloop
-
 
 	;===================================
 	; draw the stars
@@ -107,6 +63,14 @@ to2_smc:
 ;	bit	LORES
 ;	jsr	SETGR
 
+;	tax
+
+	ldx	#15
+make_orig_stars:
+	jsr	make_new_star
+	dex
+	bpl	make_orig_stars
+
 	;===================================
 	; starloop
 
@@ -115,49 +79,8 @@ big_loop:
 	ldx	#15
 star_loop:
 
-	;==============================
+	;===================
-	; get X/Z
+	; erase old
-	;	X=V(A(P),Z(P))
-
-	; position Z
-	lda	star_z,X
-	clc
-	adc	#$20		; tables in $20-$5F
-	sta	xload_smc+2
-	sta	xload2_smc+2
-
-	; get XX
-	ldy	star_x,X
-xload_smc:
-	lda	$5F00,Y
-	sta	XX
-
-	bmi	new_star	; if <0
-	cmp	#40
-	bcs	new_star	; bge >40
-
-	;==============================
-	; get Y/Z
-	;	Y=V(B(P),Z(P))
-
-	; get YY
-
-	ldy	star_y,X
-xload2_smc:
-	lda	$5F00,Y
-	sta	YY
-
-	bmi	new_star	; if <0
-	cmp	#40
-	bcs	new_star	; bge >39
-
-	;Z(P)=Z(P)-1
-	dec	star_z,X
-	beq	new_star	; if Z=0 new star
-
-	; draw the star
-
-draw_star:
 
 	;4 COLOR=0
 	lda	#$00
@@ -169,23 +92,107 @@ draw_star:
 	lda	oldy,X
 	jsr	PLOT		; PLOT AT Y,A
 
+	;===========================
+	; position Z
+
+;	lda	star_z,X
+;	beq	new_star	; should never happen
+;	sta	DIVISOR
+
+	; DIVISOR always star_z,X
+
+	;==============================
+	; get Y/Z
+	;	Y=V(B(P),Z(P))
+
+	; get YY
+
+	lda	star_y,X	; get Y of star
+
+	jsr	do_divide
+
+	sta	YY		; YY
+
+	bmi	new_star	; if <0
+	cmp	#40
+	bcs	new_star	; bge >39
+
+
+	;==============================
+	; get X/Z
+	;	X=V(A(P),Z(P))
+
+	; get XX
+
+	lda	star_x,X	; get X of start
+
+	jsr	do_divide
+
+;	sta	XX
+	tay
+
+	bmi	new_star	; if <0
+	cpy	#40
+	bcs	new_star	; bge >40
+
+	;========================
+	; adjust Z
+
+	;Z(P)=Z(P)-1
+	dec	star_z,X
+	beq	new_star	; if Z=0 new star
+
+	; draw the star
+
+draw_star:
+
 	; COLOR=15
-	dec	COLOR
+	dec	COLOR		; color from $00 (black) to $ff (white)
+	txa
+	ror
+	bcs	not_far
+	jsr	NEXTCOL
+
+;	ror
+;	jsr	NEXTCOL
+;	lda	#$55
+;	sta	COLOR		; FF -> 7F
+not_far:
 
 	;PLOT X,Y
 	; O(P)=X:Q(P)=Y
 
-	ldy	XX
+;	ldy	XX		; XX already in Y
-	sty	oldx,X
+	sty	oldx,X		; save for next time to erase
 
-	lda	YY
+	lda	YY		; YY
-	sta	oldy,X
+	sta	oldy,X		; ;save for next time to erase
 	jsr	PLOT		; PLOT AT Y,A
 
-				; a should be F0 or 0F here?
+				; a should be F0/20 or 0F/02 here?
-	bne	done_star
+	bne	done_star	; bra
 
 new_star:
+	jsr	make_new_star	;
+
+done_star:
+	;7NEXT
+
+	dex
+	bpl	star_loop
+
+	lda	#120
+	jsr	WAIT		; A is 0 after
+
+	; GOTO2
+	beq	big_loop	; bra
+
+
+	;===========================
+	; NEW STAR
+	;===========================
+
+make_new_star:
 	;IFX<0ORX>39ORY<0ORY>39ORZ(P)<1THEN
 	;	A(P)=RND(1)*64
 	;	B(P)=RND(1)*64
@@ -195,7 +202,8 @@ new_star:
 	lda	$F000,Y
 	sta	star_x,X	; random XX
 
-	lda	$F001,Y
+color_lookup:
+	lda	$F100,Y
 	sta	star_y,X	; random YY
 
 	lda	$F002,Y
@@ -205,21 +213,53 @@ new_star:
 
 	inc	FRAME
 
+	rts
 
-done_star:
+	;=============================
-	;7NEXT
+	; do divide
+	;=============================
+	; Z is in divisor
+	; x/y is in A
 
-	dex
+do_divide:
-	bpl	star_loop
+	; A was just loaded so flags still valid
+	php
+	bpl	not_negative
 
-	lda	#100
+	eor	#$ff
-	jsr	WAIT		; A is 0 after
+	clc
+	adc	#1	; invert
+
+not_negative:
+
+	ldy	#$ff		; QUOTIENT
+div_loop:
+	iny			;	inc	QUOTIENT
+	sec
+	sbc	star_z,X	; DIVIDEND=DIVIDEND-DIVISOR
+	bpl	div_loop
+
+	; write out quotient
+	tya			; lda	QUOTIENT
+
+	plp
+	bpl	pos_add
+
+	eor	#$ff
+	sec
+	bcs	do_add
+
+pos_add:
+	clc
+do_add:
+	adc	#20
+
+early_out:
+	rts
 
-	; GOTO2
-	beq	big_loop	; bra
 
 	; for BASIC bot load
 
 	; need this to be at $3F5
-
+	; it's at 8A, so 6B
 	jmp	small_starfield

graphics/gr/starfield/starbot_lookup.s

@@ -0,0 +1,235 @@
+; starfield tiny -- Apple II Lores
+
+; by Vince `deater` Weaver
+
+; actually too fast
+
+; 189 bytes - original
+; 184 bytes - move DIVIDEND to A
+; 173 bytes - move variables to 0 page. limits to 16 stars but that's fine?
+; 171 bytes - adjust random # generator
+; 170 bytes - can do sty zp,x
+; 163 bytes - lose the cool HGR intro
+; 161 bytes - re-arrange RNG location
+; 158 bytes - ra-arrange a lot to remove need for XX
+
+COLOR		= $30
+
+QUOTIENT	= $FA
+DIVISOR		= $FB
+DIVIDEND	= $FC
+XX		= $FD
+YY		= $FE
+FRAME		= $FF
+
+oldx		= $80
+oldy		= $90
+star_x		= $A0
+star_y		= $B0
+star_z		= $C0
+
+;oldx		= $1000
+;oldy		= $1040
+;star_x		= $2000	; should be 0, not used as we never /0
+;star_y		= $2040
+;star_z		= $2080
+
+
+LORES		= $C056		; Enable LORES graphics
+
+HGR2		= $F3D8
+HGR		= $F3E2
+PLOT		= $F800		; PLOT AT Y,A (A colors output, Y preserved)
+SETGR		= $FB40
+WAIT		= $FCA8		; delay 1/2(26+27A+5A^2) us
+
+small_starfield:
+
+	;0GR:DIMV(64,48):FORZ=1TO48:FORX=0TO64:V(X,Z)=(X*4-128)/Z+20:NEXTX,Z
+
+	jsr	SETGR
+
+	; init the X/Z tables
+
+	ldy	#63	; Y==z	 for(z=1;z<64;z++) {
+xloop:
+	ldx	#0	; X==x
+zloop:
+	lda	#$ff
+	sta	QUOTIENT
+;	stx	DIVIDEND
+	sty	DIVISOR
+	txa		; DIVIDEND
+div_loop:
+	inc	QUOTIENT
+	sec
+;	lda	DIVIDEND
+	sbc	DIVISOR
+;	sta	DIVIDEND
+	bpl	div_loop
+
+	; write out quotient
+
+	lda	QUOTIENT
+	pha
+	clc
+	adc	#20
+to_smc:
+	sta	$5F80,X
+
+	inx
+	bpl	zloop	; loop until 128
+
+
+	; reverse and write out negative parts
+
+	ldx	#0
+negative_loop:
+	pla
+	eor	#$ff
+	sec
+	adc	#20
+to2_smc:
+	sta	$5F00,X
+	inx
+	bpl	negative_loop
+
+	dec	to_smc+2
+	dec	to2_smc+2
+
+	dey
+	bne	xloop
+
+
+	;===================================
+	; draw the stars
+	;===================================
+
+;	bit	LORES
+;	jsr	SETGR
+
+	;===================================
+	; starloop
+
+	;2FORP=0TO5
+big_loop:
+	ldx	#15
+star_loop:
+
+	;===================
+	; erase old
+
+	;4 COLOR=0
+	lda	#$00
+	sta	COLOR
+
+	;PLOT O(P),Q(P)
+
+	ldy	oldx,X
+	lda	oldy,X
+	jsr	PLOT		; PLOT AT Y,A
+
+	;===========================
+	; position Z
+
+	lda	star_z,X
+	clc
+	adc	#$20		; tables in $20-$5F
+	sta	xload_smc+2
+	sta	xload2_smc+2
+
+	;==============================
+	; get Y/Z
+	;	Y=V(B(P),Z(P))
+
+	; get YY
+
+	ldy	star_y,X	; get Y of star
+xload2_smc:
+	lda	$5F00,Y		; lookup Y/Z
+	sta	YY		; YY
+
+	bmi	new_star	; if <0
+	cmp	#40
+	bcs	new_star	; bge >39
+
+
+	;==============================
+	; get X/Z
+	;	X=V(A(P),Z(P))
+
+	; get XX
+	ldy	star_x,X	; get X of start
+xload_smc:
+	lda	$5F00,Y		; lookup X/Z
+	tay			; XX
+
+	bmi	new_star	; if <0
+	cpy	#40
+	bcs	new_star	; bge >40
+
+	;========================
+	; adjust Z
+
+	;Z(P)=Z(P)-1
+	dec	star_z,X
+	beq	new_star	; if Z=0 new star
+
+	; draw the star
+
+draw_star:
+
+	; COLOR=15
+	dec	COLOR		; color from $00 (black) to $ff (white)
+
+	;PLOT X,Y
+	; O(P)=X:Q(P)=Y
+
+;	ldy	XX		; XX already in Y
+	sty	oldx,X		; save for next time to erase
+
+	lda	YY		; YY
+	sta	oldy,X		; ;save for next time to erase
+	jsr	PLOT		; PLOT AT Y,A
+
+				; a should be F0 or 0F here?
+	bne	done_star	; bra
+
+new_star:
+	;IFX<0ORX>39ORY<0ORY>39ORZ(P)<1THEN
+	;	A(P)=RND(1)*64
+	;	B(P)=RND(1)*64
+	;	Z(P)=RND(1)*48+1:GOTO7
+
+	ldy	FRAME
+	lda	$F000,Y
+	sta	star_x,X	; random XX
+
+	lda	$F001,Y
+	sta	star_y,X	; random YY
+
+	lda	$F002,Y
+	and	#$3f		; random ZZ 0..63
+	ora	#$1		; avoid 0
+	sta	star_z,X
+
+	inc	FRAME
+
+
+done_star:
+	;7NEXT
+
+	dex
+	bpl	star_loop
+
+	lda	#100
+	jsr	WAIT		; A is 0 after
+
+	; GOTO2
+	beq	big_loop	; bra
+
+	; for BASIC bot load
+
+	; need this to be at $3F5
+
+	jmp	small_starfield