user-level: 0.665 permissions: 0.640 PID: 0.606 register: 0.575 risc-v: 0.571 semantic: 0.571 debug: 0.562 hypervisor: 0.549 TCG: 0.532 boot: 0.527 network: 0.513 arm: 0.512 VMM: 0.503 assembly: 0.493 device: 0.482 performance: 0.481 ppc: 0.469 files: 0.445 virtual: 0.429 peripherals: 0.429 vnc: 0.410 mistranslation: 0.406 KVM: 0.404 x86: 0.395 socket: 0.392 architecture: 0.382 kernel: 0.346 graphic: 0.291 i386: 0.213 FPU incorrect on Mac OS X I am using the 0.13.0 release version of QEMU on Mac OS X 10.6.4. I work for a university and the affected guest OS is our own research OS. I believe I found a bug in QEMU's FPU emulation, which only triggers on the Mac. You can reproduce the problem by booting the attached ISO image. Investigating the problem, I found that the lua interpreter in our loader component (called "ned") internally uses doubles to represent all lua-numbers. These doubles are showing completely wrong values on QEMU/Mac, resulting in the lua code not processing properly. I also attached a patch which fixes the problem for me. The attached ZIP-file also contains "before" and "after" screenshots. Note that booting the ISO on a real machine or on a Linux-QEMU always shows the correct "after" behavior. Only QEMU on the Mac exhibits the wrong "before" behavior without my patch. The patch might break other systems setting the CONFIG_BSD flag, so maybe the preprocessor should check for __APPLE__ instead to make the fix Mac-only. Looks like the ISO from comment #4 (thanks for attaching that one!) shows the correct behavior with up to date QEMU 2.7. Also, the affected softfloat code has been completely reworked in between (e.g. with commit cf67c6bad56d43e6d60), so I assume this has been fixed sometimes in the past years. I can confirm that recent QEMU works fine. Sorry, I forgot about this bug and did not update it. On Sep 12, 2016, at 5:03 PM,