Advanced Micro Devices Inc (AMD)

[dacaw]

Saving SSE registers.

It has done since Win 98.

Just because there's no push/pop instructions doesn't mean you can't save them. They can always be mov'd to memory. Its just that he doesn't see a push xmm0 as he expected.

OTOH the MMX & FPU state does not seem to be saved under a LONG MODE context switch with WinXP64 and that's why x87, MMX and 3DNow are not available - a reasonable tradeoff given the enhanced SSE under x86-64, the ease of moving xmm values to and from 64-bit registers.

Its worth noting that LONG MODE SSE & SSE2 is much better than SSE & SSE2 under 32-bit since AMD64 enhances the interface between the SSE regs and the 64-bit GP regs.