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Large ram allocation

Discuss issues related to the fx-9860G Software Development Kit
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Calculators: Casio Cfx Series, Casio fx-9860 GII

Large ram allocation

Postby Jsec42 » Fri Sep 11, 2015 12:02 pm

Alright, I am going to be making an emulator for the ti-84+(and others) to run on the Casio fx-9860gii-2. However, I am running into a bit of a problem. In order to achieve optimal emulation speed, I need to A. Hold the 64kb physical address space of the Z80 in ram(I don't need the ROM file in ram, because I can just seek in/out 16kb pages when the Virtual ASIC is instructed to swap pages ;)), and B. Hold the 128kb of ram available to the Calculator in a separate buffer. This would be trivial on a PC, but it poses a bit of a challenge on the Calculator. This being caused by the 32kb work ram limitation, and the 48kb restriction on heap ram <_< . However, if I am correct, the program itself is copied into a buffer that is 512kb large. Would it be possible to allocate some space in this "program heap"? If not, is there a place where I can allocate the amount of ram I need? Thanks in advance :)

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Re: Large ram allocation

Postby SimonLothar » Fri Sep 11, 2015 4:29 pm

Hi,

the GII-calculators possess 512 KiB RAM. The upper 256 KiB of which - starting at physical address 0x88040000 - is not used, as I understand it.
I filled this area with 0xAAAAAAAA and played around with some build-ins - including a storage mem optimization, which should be a RAM consuming one - and the area has not been touched by the system.
Perhaps this could come in handy.
I'll be back!

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Posts: 24
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Calculators: Casio Cfx Series, Casio fx-9860 GII

Re: Large ram allocation

Postby Jsec42 » Sun Sep 13, 2015 3:29 am

That is PERFECT! Turns out I am (very) good at manually allocating ram to my programs(I'm used to the ti-83+ series free ram buffers) so that will take care of my ram needs(and then some). Now I just need to figure out how the save states will work.

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Posts: 24
Joined: Sun Aug 31, 2014 4:48 pm
Calculators: Casio Cfx Series, Casio fx-9860 GII

Re: Large ram allocation

Postby Jsec42 » Sun Sep 13, 2015 3:31 am

It is fun to have so much ram to work with :P

PostThis post was deleted by SimonLothar on Wed Sep 16, 2015 3:39 pm.
Reason: erroneous post

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