My middle paragraph up-thread proposes that you can emulate it much faster than we're doing now, at full precision with integer SIMD and a specialized JIT. I'll

My middle paragraph up-thread proposes that you can emulate it much faster than we're doing now, at full precision with integer SIMD and a specialized JIT. I'll reiterate the 80-bit softfloat stuff I've seen in use now is not really optimized. I suspect that beating the performance of a cpu on x87 from the era where x87 was relevant is somewhere between realistic and trivial. Beating a modern cpu on x87 from another architecture still feels possible (but it's a less useful thing to spend time on). > Even lowering the precision of the x87 unit isn’t sufficient as that only reduces the precision of the mantissa not the exponent. I don't know what you mean by "isn't sufficient". To be clear, I'm speaking from experience emulating x86 games on low resource arm devices, where I had success emulating x87 in lower precision. For QEMU, IMO the bigger performance issue is that it doesn't natively JIT _any_ FPU or vector instructions, and the indirect memory mapping hurts general performance quite a bit too.