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Forums > C64 Coding > Show Koala Pic
2014-11-09 19:57
Ejner

Registered: Oct 2012
Posts: 43
Show Koala Pic

I'm sure noone here has any problems with showing a simple Koala picture, but I came across this piece of code on codebase64.org and wondered why this had to be done so complicated...?

http://codebase64.org/doku.php?id=base:calculate_vic_settings_f..

In TurboAssembler it's pretty simple to calculate the VIC settings, see my example below. Isn't something similar possible with KickAssembler? Just wondering...

Example in TurboAssembler:

;---------------------------------------
;        Show Koala
;---------------------------------------
koala    = $6000
screen   = $5c00
;---------------------------------------
bank     = koala/$4000

         *= $1000

         lda #$3b
         sta $d011
         lda #koala-($4000*bank)/1024
         ora #(screen-($4000*bank))/64
         sta $d018
         lda #$d8
         sta $d016
         lda $dd02
         ora #%00000011
         sta $dd02
         lda $dd00
         and #%11111100
         ora #3-bank
         sta $dd00

         ldx #0
copy     lda koala+$1f40,x
         sta screen,x
         lda koala+$2040,x
         sta screen+$0100,x
         lda koala+$2140,x
         sta screen+$0200,x
         lda koala+$2228,x
         sta screen+$02e8,x
         lda koala+$2328,x
         sta $d800,x
         lda koala+$2428,x
         sta $d900,x
         lda koala+$2528,x
         sta $da00,x
         lda koala+$2610,x
         sta $dae8,x
         inx
         bne copy
         lda koala+$2710
         sta $d021
         lsr a
         lsr a
         lsr a
         lsr a
         sta $d020

         lda #0
         cmp $0277     ;wait for key
         bne *-3

         lda $dd02
         ora #%00000011
         sta $dd02
         lda $dd00
         and #%11111100
         ora #%00000011
         sta $dd00
         lda #$1b
         sta $d011
         lda #$15
         sta $d018
         lda #$c8
         sta $d016

         jmp $9000
;---------------------------------------

Note: The result of "bank = koala/$4000" is an integer.
 
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2015-02-23 06:54
Oswald

Registered: Apr 2002
Posts: 5076
soci, thats a neat idea, tho I cant think of a scenario where it would be useful :) maybe some demo effect with lots of prepped csets.
2015-02-23 07:30
Dr.j

Registered: Feb 2003
Posts: 277
Soci , hehe i don't like to kill a fly with RPG but
what do you mean
by:
$0000 | bits(bitmap) where is the bits function? or i miss something.
and later:
and #~(screen[14:16] || []) hehe for not a C coders
could you make a friendly explain ? (you can do it on
private if you prefer)
2015-02-23 08:14
Flavioweb

Registered: Nov 2011
Posts: 463
I think Soci is talking about 64tass:
http://tass64.sourceforge.net/
2015-02-23 10:18
Dr.j

Registered: Feb 2003
Posts: 277
oh Flavioweb ok. i am kickass person so i leave it aside
for now hehe
2015-02-23 19:35
soci

Registered: Sep 2003
Posts: 479
Too much late coding yesterday ;) It would go even more off topic if I'd go into details in this thread.

The code fragment was only a demonstration about constructing $d018 values without using divisions and shifts.

Normally I use some variant of this:
lda #((font >> 10) & $0f) | ((screen >> 6) & $f0)
sta $d018
lda $dd00
ora #3
eor #font >> 14
sta $dd00
Even if this version is wasting 2 bytes half the time for the $dd00 calculation.
2015-02-23 19:38
chatGPZ

Registered: Dec 2001
Posts: 11293
why not just store a fixed value to $dd00 though? i dare to say that "properly" ORing the value is very rarely needed - certainly almost never in the usual setup code at the start of your intro/demo/whatever :)
2015-02-23 20:13
soci

Registered: Sep 2003
Posts: 479
Not sure why. I just checked and even my one filers are mostly doing the masking, where there's no chance of loader interference.

It must be tradition then.

So I now declare trademark rights on the ora/eor version. It may only identify genuine Singular productions ;)
2015-02-23 20:23
chatGPZ

Registered: Dec 2001
Posts: 11293
i see this often, also with eg $01 or $d011 .... people must have learned it somewhere :)
2015-08-31 14:57
The Phantom

Registered: Jan 2004
Posts: 360
Why not give an example of code? Unabridged CODE. No documentation per line of code, just CODE.

Screen Ram - $7f40-$8327 ?
Color Ram - $8338 (or is it $8328)-$8711?

My code, and it doesn't display proper at all.. Like missing lines...

Lda $dd02
and #$03
sta $dd02

lda $dd00
and #$fc
ora #$02
sta $dd00

And of course I follow with:
lda #$18
ldx #$f8
ldy #$3b
sta $d018
stx $d016
sty $d011

Not known if my image will show...
<a href="http://s48.photobucket.com/user/festeezio/media/koala_zpsxtctbx.." target="_blank"><img src="http://i48.photobucket.com/albums/f245/festeezio/koala_zpsxtctb.." border="0" alt=" photo koala_zpsxtctbxw4.png"/></a>

If it doesn't, here's a direct link..
http://i48.photobucket.com/albums/f245/festeezio/koala_zpsxtctb..

Any suggestions as to what I'm doing wrong?
Image is at $6000. The 2 RAMS mentioned are being read and plotted to the screen/color area.
2015-08-31 17:00
soci

Registered: Sep 2003
Posts: 479
                                                *= $6000
>6000                                   pic     .binary "a.kla",2

                                                *= $0801
>0801   0b 08 df 07                             .word +, 2015
>0805   9e 32 30 36 31 00                       .null $9e, ^start
>080b   00 00                           +       .word 0

.080d   a2 00           ldx #$00        start   ldx #0
.080f   a0 04           ldy #$04                ldy #4
.0811   bd 40 7f        lda $7f40,x     lp      lda pic+8000,x
.0814   9d 00 44        sta $4400,x             sta $4400,x
.0817   bd 28 83        lda $8328,x             lda pic+9000,x
.081a   9d 00 d8        sta $d800,x             sta $d800,x
.081d   e8              inx                     inx
.081e   d0 f1           bne $0811               bne lp
.0820   ee 13 08        inc $0813               inc lp+2+range(4)*3
.0823   ee 16 08        inc $0816
.0826   ee 19 08        inc $0819
.0829   ee 1c 08        inc $081c
.082c   88              dey                     dey
.082d   d0 e2           bne $0811               bne lp

.082f   8c 20 d0        sty $d020               sty $d020
.0832   ad 10 87        lda $8710               lda pic+10000
.0835   8d 21 d0        sta $d021               sta $d021

.0838   ad 00 dd        lda $dd00               lda $dd00
.083b   29 fc           and #$fc                and #$fc
.083d   09 02           ora #$02                ora #$02
.083f   8d 00 dd        sta $dd00               sta $dd00

.0842   a9 18           lda #$18                lda #$18
.0844   a2 f8           ldx #$f8                ldx #$f8
.0846   a0 3b           ldy #$3b                ldy #$3b
.0848   8d 18 d0        sta $d018               sta $d018
.084b   8e 16 d0        stx $d016               stx $d016
.084e   8c 11 d0        sty $d011               sty $d011
.0851   4c 51 08        jmp $0851               jmp *
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