Okay, I'm trying to classify this bug report as either 'user-mode' or 'system-mode'. Let's see what the report says. The issue is that certain programs cause QEMU to crash with a "tcg fatal error" and an assertion failure. The code provided seems to be executing some assembly instructions via a buffer. It compiles to an executable and runs under QEMU using both -user and -system modes. In user-mode, QEMU typically emulates a CPU in a way that's similar to running native code but with some modifications for performance. System-mode involves more hardware emulation, like devices and peripherals. Looking at the provided assembly snippets, they don't seem to interact with any system-level components or devices. Instead, they're using various x86 instructions, including AVX and other CPU-specific operations. The crash happens when these instructions are executed, which suggests it's a problem in how QEMU's TCG (Translation-Block based CPU emulator) handles certain machine code sequences. Since the issue occurs in both user and system modes but doesn't involve any device-level interactions or higher privileges beyond what an application might use, I think this is more related to user-mode. It seems like it's a problem with how QEMU translates or executes these specific instructions rather than anything related to system hardware emulation. user