Well, they would still need the raw buffer for every shot, no?
According to the specs, my A570 IS has 1.5 FPS burst mode (I never tried it though). Since people can use slower SD cards, it is reasonable to assume that there is such buffer.
Now, if this buffer can be found, and it is accessible by the ARM core, I think a lot of cool stuff can be done. For example, moving all the ROM in there, to be able to hook functions directly from the ROM.
If they skip lines they don't need all of it, do they? Similarly to video mode... speed up readout by reading less. But maybe someone who has one of these cameras (S series? Others?) tell us how they work.
Since many of the cameras have some sort of burst mode, where you can take pictures at a faster speed than you can write on the SD card,
I would guess that there is some buffer where this information is stored while it awaits for the SD card (different from the jpg/raw data buffer).Do you happen to know if this memory can be directly accessed by the ARM core?
Well, I am a total newbie at ARM and especially at how the Canon cameras work,
but would it be possible to have a program that scans all the address ranges to try to find r/w memory? What happens if you read or write to an invalid location? Do you get an exception?
Which specific camera do you have in mind ? Most recent (digic-II and later) canon P&S cameras will shoot continuously at the same rate until the card is full. Some do use multiple raw buffers, but the reason for this isn't clear. Perhaps it lets them do shooting and jpeg encoding in parallel.
The existence of additional memory is unwarranted speculation on your part. My guess is that it wouldn't be additional memory, it would be multiple locations for of the normal buffers (like the dynamic raw buffer). If this was not the case, a copy would be required, which would be counter productive. Thus it would be in the same 32-128 meg region of memory already known. There may well be more memory we can use, but finding it will require actual reverse engineering, not guessing.
I'd suggest that speculation is pointless until you fix that.
I answered this question for you before. http://chdk.setepontos.com/index.php/topic,3360.msg30999.html#msg30999If you aren't willing to do the basic work required to answer your question, there's little point in speculating.
There is a VERY good reason why there might be extra memory, and the reason is that memory chips usually come in sizes that are powers of 2. If you take the jpeg buffer and the raw buffer, which are the biggest buffers, you will see that there is quite a bit of memory left, especially for cameras with less than 8MP.
No, you did not answer me that at all. You just told me your way of doing it.
Huh ? We already know the size of the various memory regions (including the one that corresponds to main memory), and they are significantly larger than the portions whose purpose we know. Figuring out what parts we can re-use requires actually digging in to the disassembly.
If you are unwilling to take the short amount of time required to get the full answer, it's extremely unlikely you will expend the much greater effort to do something useful with it. Of course, if you'd actually read the link I'd provided, you would have seen detailed information about the memory layout and protection regions of several cameras.
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