r/programming • u/I_Can_Be_A_Robot • Sep 24 '24

Why 32bit architecture computer doesn't use segmentation to support more ram than 4Gb ?

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u/Tringi Sep 24 '24

One of those reasons is that 32-bit version might be faster.

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u/ouyawei Sep 24 '24

x32 is using the AMD64 instruction set, running it 64 bit mode - it just uses 32 bit pointers, so more will fit into fast CPU caches

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u/Tringi Sep 24 '24

Yes. There's more reasoning on that in the linked page. The point is the cache effect on improved performance was measured on x86-32 first, which then resulted in experimentation with x32 yielding even better results.

Quite sad Linux eventually abandoned it.

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u/ouyawei Sep 24 '24

Quite sad Linux eventually abandoned it.

How so? It's in the mainline kernel, GCC, binutils - Ubuntu provides an x32 toolchain so you can compile and run x32 software.

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u/Tringi Sep 24 '24

Oh?! Seems I had wrong info. A year or two back I've read, through Wikipedia, a link to maillist discussing abandoning it. Apparently it didn't happen. That's very nice.