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HP Forum Archive 17

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HP50G Memory
Message #1 Posted by Chan Tran on 13 Aug 2007, 10:12 a.m.

Just got a 50G. Found out that the memory that matter most is limited to 240kB. I have the 48GX and with an expansion card I have a max of 256kB. So I can't create nor transfer a larger GROB on the 50G than on the 48GX no matter what I do.

      
Re: HP50G Memory
Message #2 Posted by hugh steers on 13 Aug 2007, 10:20 a.m.,
in response to message #1 by Chan Tran

is this some saturn architectural weirdness? i'm seeing 400k free under hpgcc.

            
Re: HP50G Memory
Message #3 Posted by Tim Wessman on 13 Aug 2007, 12:38 p.m.,
in response to message #2 by hugh steers

Yes, it is some saturn architectural weirdness. Saturn only has 5 nibble addressing, so it can only address 512k at once. Main RAM (HOME) is 256k, but part is used for stack, hidden directory, etc.

In HPGCC you are seeing main RAM, hidden ram (~90K - the leftover from the 128k bankj reserved for the ARM OS) and IRAM (port 1) turned into one contiguous block. It is a 512k RAM chip, but part is reserved for the ARM emulator so you never have the full 512.

TW

Edited: 13 Aug 2007, 12:43 p.m.


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