| |
SIDWAVE
Account closed
Registered: Apr 2002
Posts: 2238 |
DE00-DFFF
I read just about everything I could find about this memory area, but I remembered something, perhaps from a chat on IRC or something..
This mem area contains the program-counter, the last accessed line nr, cycle-counter, well - just about everything the machine does.
Is this true ?
Who knows anything ?
I can dig that any expansions put into the machine must have some input data, so naturally there has to be some important info in this memblock - but which ones exactly ?
I also read that it don't nessecarily behave the same way on every C64.
So ?
Help!!
I am also looking for a way to read the read-only registers of the SID.
My friend Kaze/TST did it once, but that program is lost forever, and he didn't code since 1988 on C64. damn.
The program was running a modified KERNAL, and it enabled us to write the music while playing, out to disk as a D400+ dump - but it was way to slow and the disk just got filled up very fast.
But it worked!
|
|
... 23 posts hidden. Click here to view all posts....
|
| |
Hoogo
Registered: Jun 2002
Posts: 105 |
>about DE00+ i found i could fuck up things
>by poking values to it.
Then you might have inserted a cardridge? |
| |
WVL
Registered: Mar 2002
Posts: 902 |
groepaz : you can clear your dummy area every frame with $ea for example to see if something was written or not.
problem remains that then you cannot detect if $ea (or any other number was written at all :(()
solution :
3 dummy buffers :
1 filled with $00, the other with $80 for example. 1 filled with the last data that was written to the sid.
every frame you write $00 to buffer 1 and $80 to buffer 2. then you jsr to the tune, which you have to 'adapt' to write to both your buffers.
then you have to check if something was written to the dummy buffers.
a simple
lda buffer1,x
bne somethingwritten
lda buffer2,x
cmp #$80
bne somethingwritten
..-> register x was not written
somethingwritten :
jsr storewrite
sta sidbuffer,x
sta $d400,x
will do...
and why would rambones want to do this? to save cycles in a darn-hard-cycle-eating-mega part? :)
I've been thinking about this myself too a bit, there's one part where I could really use the extra cycles gained...
(which I always only need for a couple of frames.. so...)
rambones : good luck
|
| |
Hoogo
Registered: Jun 2002
Posts: 105 |
Well, yes, if you can change the music-routine then you can perfectly detect every write to the sid. But what if you want to examine a music done in an unknown, tricky music-routine? |
| |
WVL
Registered: Mar 2002
Posts: 902 |
in case of a tricky music routine...
well... :)
maybe the easiest thing would be to find the pointers, and calling it twice.. or something ;)
you could also just have 1 buffer to catch the writes in, just put a very unusual value in there, and you should be alright in 99% of the cases, i think..
|
| |
Graham
Account closed
Registered: Dec 2002
Posts: 990 |
99.609375 actually :D and even more if you take into account that some values are more likely than others. |
| |
SIDWAVE
Account closed
Registered: Apr 2002
Posts: 2238 |
Quote: @rambones: Could you care to explain why you want the data of a whole tune for a post processing scenario? Since, I guess you're aiming for the c64 as target machine of your idea? I'm just curious and if you don't want to reveal your secrets I can surely wait..
Well, I want to attempt to make a universal player.
Just convert any tune to this dumpformat (crunched), and then play it using a STA d400,x
If I can crunch it enough that is...
|
| |
iopop
Registered: Dec 2001
Posts: 317 |
Quote: Well, I want to attempt to make a universal player.
Just convert any tune to this dumpformat (crunched), and then play it using a STA d400,x
If I can crunch it enough that is...
Ok, I thoguht you wanted to do some kind of tool that could filter selected parts of the tune etc. Though, the sampled data is not the amplitude but parameters creating the amplitude. So, that might not have been possible anyhow. |
| |
chatGPZ
Registered: Dec 2001
Posts: 11386 |
uhmz like i mentioned before.... this kind of tool already exists :o) its called "music cruncher" and works exactly like you say. |
| |
Hoogo
Registered: Jun 2002
Posts: 105 |
I'm thinking about an assembler-interpreter for the music-routine. That will surely detect any access to the sid. I have done such an interpreter ages ago, maybe I'll have a look at it again. |
| |
Clarence
Registered: Mar 2004
Posts: 121 |
Quote: uhmz like i mentioned before.... this kind of tool already exists :o) its called "music cruncher" and works exactly like you say.
Can you tell me who made this tool and where can I find it? If you refer to the Spiders Crews 'Music Rastertime Cruncher', that doesn't crunch the dumped data at all. |
| Previous - 1 | 2 | 3 | 4 - Next |
