The problem arises during the execution of RISC-V RVV instructions when using `vmv.v.x` with `e64`, where the vector length (`vl`) equals `vl_max`. The assertion failure occurs because the code attempts to use a 32-bit operation for a 64-bit context, leading to an incorrect instruction generation. This issue is related to handling specific vector operations and their corresponding data types within the QEMU emulator.

**Answer:** runtime