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Index > Main > Extending my 32-bits to 64-bits...

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smiddy



Joined: 31 Oct 2004
Posts: 559
smiddy
Hi,

This is a general question but applies to OS programming as I am working on a way to make an ACPI compatible OS. To do so I need to be able to look at and extend 32-bit addition and subtraction (et al math functions). I intend to get to Long Mode eventually, but the first step in the OS Requirements is Query System Address Map, INT 15h, E820h, which has 64-bit numbers for addressable memory. In real mode when using that interrupt I am at a loss as to what to use in order to use 64-bit addition and subtraction so that I can make a memory map of my own, prior to getting to RAX (and the like) registers. I thought of MMX and XMM registers...but they appear to be setup in weird fashions and I am looking for something fairly straght forward like an EAX or RAX register...

Any thoughts or suggestions welcomed, thanks!
Post 06 Mar 2010, 23:02
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baldr



Joined: 19 Mar 2008
Posts: 1651
baldr
smiddy,

Look here.
Post 07 Mar 2010, 08:32
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smiddy



Joined: 31 Oct 2004
Posts: 559
smiddy
Thanks, that will do it! Smile
Post 07 Mar 2010, 12:46
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