sysin code | name

The specified system call has just been initiated and the process has entered kernel mode.

The concept of system call supported by dbx is that provided by procfs(4). These are traps into the kernel as enumerated in /usr/include/sys/syscall.h.

This is not the same as the ABI notion of system calls. Some ABI system calls are partially implemented in user mode and use non-ABI kernel traps. However, most of the generic system calls (the main exception being signal handling) are the same between syscall.h and the ABI.