scroll: work on smaller version

This commit is contained in:
Vince Weaver 2022-05-08 01:14:52 -04:00
parent 0d9db2963f
commit 4715dfaf85
2 changed files with 246 additions and 2 deletions

View File

@ -12,14 +12,14 @@ all: scroller.dsk
$(DOS33):
cd ../../../utils/dos33fs-utils && make
scroller.dsk: $(DOS33) HELLO DIAMOND DIAMOND_BOT RANDOM RANDOM_BOT
scroller.dsk: $(DOS33) HELLO DIAMOND DIAMOND_BOT RANDOM RANDOM_BOT RANDOM_128
cp $(EMPTY_DISK)/empty.dsk scroller.dsk
$(DOS33) -y scroller.dsk SAVE A HELLO
$(DOS33) -y scroller.dsk BSAVE -a 0xc00 DIAMOND
$(DOS33) -y scroller.dsk BSAVE -a 0x36B DIAMOND_BOT
$(DOS33) -y scroller.dsk BSAVE -a 0xc00 RANDOM
$(DOS33) -y scroller.dsk BSAVE -a 0x36B RANDOM_BOT
$(DOS33) -y scroller.dsk BSAVE -a 0x70 RANDOM_128
###
HELLO: hello.bas
@ -51,6 +51,14 @@ random.o: random.s
###
RANDOM_128: random_128.o
ld65 -o RANDOM_128 random_128.o -C $(LINKERSCRIPTS)/apple2_70_zp.inc
random_128.o: random_128.s
ca65 -o random_128.o random_128.s -l random_128.lst
###
RANDOM_BOT: random_bot.o
ld65 -o RANDOM_BOT random_bot.o -C $(LINKERSCRIPTS)/apple2_36b.inc

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@ -0,0 +1,236 @@
; random scroll bot 128
; 141 bytes -- bot version
; 138 bytes -- no need for back jump
; 140 bytes -- load at 0x70
; 134 bytes -- enforce ZP addresses
; 133 bytes -- convert JMP to BPL
; 131 bytes -- make OUTL live in program
; 130 bytes -- use EOR instead of ADD
; 127 bytes -- don't wrap pattern lookup at 8
; 126 bytes -- use X for loop
; ***** *****
; ***** *****
; ** ** @@ @@@@@@
; ** ** @@ @@
; ** ** @@@@@@ @@@@@@ @@@@@@
; ***** ***** @@ @@ @@ @@
; ***** ***** @@@@@@ @@@@@@ @@
; by Vince `deater` Weaver
SETTEXT = $C051
FULLGR = $C052
PAGE1 = $C054
PAGE2 = $C055
LORES = $C056 ; Enable LORES graphics
HGR2 = $F3D8
PLOT = $F800 ; PLOT AT Y,A (A colors output, Y preserved)
GBASCALC = $F847 ; Y in A, put addr in GBASL/GBASH
SETGR = $FB40
WAIT = $FCA8 ; delay 1/2(26+27A+5A^2) us
GBASL = $26
GBASH = $27
OUTL = $74
OUTH = $75
PAGE = $6E
LINE = $6F
pattern1 = $f000 ; location in memory
.zeropage
.globalzp pattern_smc
.globalzp bitmap
.globalzp bitmap2
random:
jsr SETGR ; set LORES ; 70 71 72
lda #0 ; also OUTL=0/OUTH ; 73 74
bit FULLGR ; set FULL 48x40 ; 75 76 77
; bit SETTEXT
main_loop:
sta PAGE ; start at page 1
asl ; make OUTH $4 or $8 depending on value in PAGE
; which we have in A above or at end of loop
asl ; C is 0
adc #4
sta OUTH
lda #200
jsr WAIT
;============================
; draw an interleaved line
full_loop:
ldx #3
line_loop:
ldy #119
screen_loop:
tya ; extrapolate X from Y
; and #$7 ; could be bigger?
; tax
pattern_smc:
lda pattern1,Y
inner_loop_smc:
sta (OUTL),Y
dey
bpl screen_loop
;=================================
; move to next pattern
scroll_pattern:
clc
lda pattern_smc+1
adc #8
and #$1f
sta pattern_smc+1
; move to next line by adding $80
; we save a byte by using EOR instead
lda OUTL
eor #$80 ; add $80
sta OUTL
bne line_loop
; we overflowed, so increment OUTH
inc OUTH
; lda OUTH ; check if at end
; and #$3
; bne line_loop
dex
bpl line_loop
done_bg:
;=======================================
; done drawing frame
;=======================================
;======================
; draw bitmap
ldx #7
boxloop:
txa
jsr GBASCALC ; calc address of X
; note we center to middle of screen
; by noting the middle 8 lines
; are offset by $28 from first 8 lines
; GBASL is in A at this point
clc
adc #12+$28
sta GBASL ; center x-coord and y-coord at same time
lda PAGE ; want to add 0 or 4 (not 0 or 1)
asl
asl ; this sets C to 0
adc GBASH
sta GBASH
ldy #15
draw_line_loop:
lda bitmap2,X ; get low bit of bitmap2 into carry
lsr
lda #$00 ; black is default color
ror bitmap,X ; 16-bit rotate (in memory)
ror bitmap2,X
bcc its_black
lda #$ff
its_black:
sta (GBASL),Y ; partway down screen
dey
bpl draw_line_loop
dex
bpl boxloop
;=========================
; scroll one line
; to scroll up need to add 8?
inc pattern_smc+1
; switch page
lda PAGE
tax
ldy PAGE1,X ; flip page
eor #$1
bpl main_loop ; bra
;01234567|01234567
;
; @@@@ @@@@
; @@ @@
; @@ @@
; @@ @@
; @@@@ @@@@
;
;@@@@@@@@@@@@@@@@
bitmap:
.byte $FF ;,$FF
.byte $E1 ;,$87
.byte $F9 ;,$9F
.byte $F9 ;,$9F
.byte $F9 ;,$9F
.byte $E1 ;,$87
.byte $FF ;,$FF
.byte $00 ;,$00
bitmap2:
.byte $FF
.byte $87
.byte $9F
.byte $9F
.byte $9F
.byte $87
.byte $FF
.byte $00