Okay, I need to classify this bug report as either 'user-mode' or 'system-mode'. The user is talking about supporting the Geode LX CPU in QEMU for testing compatibility. They mention that it's an i686-compatible CPU but lacks the 'long-nop' instruction. Hmm, user-mode issues usually involve applications running on top of the OS, while system-mode involves lower-level stuff like hardware emulation or device drivers. Since this is about a CPU and its instructions, which are part of the system architecture, it's likely related to how QEMU emulates the CPU at a low level. Also, the user wants to test boundary compatibility cases using QEMU, which suggests they're dealing with system-level testing rather than application-specific issues. So, this seems more about system emulation and hardware support in QEMU. Therefore, I think it's a 'system-mode' issue. The problem involves CPU instruction support in QEMU's emulator, which is part of the system-level emulation. system