instruction

The bug report describes an issue related to how branch instructions and Protection Assist (PAC) behavior are handled in QEMU when `SCTLR_EL1.BT0` is set incorrectly in user mode. The focus on the incorrect handling of a specific instruction (`paciasp`) and its interaction with the Branch Target Identification (BTI) mechanism indicates that this is primarily an issue involving instructions rather than syscalls or runtime errors unrelated to specific instructions.