Okay, let's see. The user is working with QEMU and added a new syscall (436) but is getting ENOSYS from the MIPS application. They modified the mips/cpu_loop.c by adding an entry to mips_syscall_args. The issue seems to be that the syscall number is being calculated as env->active_tc.gpr[2] - 4000, and if that number is beyond the size of mips_syscall_args, it returns ENOSYS. Wait, the user mentioned that the ARM version has its own ARM_NR_BASE, which probably adjusts the syscall numbers correctly. The MIPS code might not be accounting for the correct base value, leading to the syscall_num being out of bounds. For example, if the actual syscall number is 436, but the base is 4000 (as in ARM's case), subtracting 4000 would give a negative number, which would definitely be beyond the array size, hence ENOSYS. So the problem is that the MIPS code isn't using a base value like ARM does. The user wants to refactor MIPS's cpu_loop.c to handle syscalls similarly to ARM. The root cause is that the syscall number calculation isn't correct for MIPS, leading to the wrong index in the syscall_args array. This is a syscall handling issue because the syscall number isn't being adjusted properly, causing it to fall into the ENOSYS case. The classification options are instruction, syscall, or runtime. Since the problem is about the syscall number not being handled correctly, the category should be "syscall". syscall