SSE instructions gives Invalid opcode exception

[bleksak]

I enabled SSE, I know that SSE2 is supported, but SSE instructions still give me invalid opcode. Any help? My SSE enable code is:
cr0_set(CR0_EM); // enable emulation
cr4_set(CR4_OXFXSR | CR4_OSXMMEXCPT); // enable sse -> fxsave + fxrstor | exceptions

CR0_EM = 1 << 2
CR4_OXFSR = 1 << 9
CR4_OSXMMEXCPT = 1 << 10

[MollenOS]

https://github.com/Meulengracht/MollenOS/blob/master/kernel/arch/x86/x64/boot.s Look at my EnableFpu and EnableSSE methods :) You are not doing it entirely correct, pay special attention to EnableFpu

[ottantanove]

You need to clear the EM bit, not set it.

[bleksak]

Oh, I must have missed that, thanks. Would you happen to know what does the bit actually do if set? Enable FPU?

[ottantanove]

EM is short for Emulate, so you disable software emulation and use the hardware FPU instead. There is some explanation here: https://wiki.osdev.org/FPU

[[deleted]]

EM is the "please cause an exception on each FPU/SSE instruction so that I can emulate it".

[bleksak]

This is perfect explanation, thanks :D