Because of peculiarities in how system calls are returned from, single stepping executes some system calls and the instruction following them in a single step. Statetrace now patches the executable image when it detects a system call to force "correct" behavior, aka the appearance of stepping one instruction every single time.
--HG--
extra : convert_revision : ac6243a2e00ff98f827b005efd27b4dc5be4f774
The address of the stackpointer proceeding the vector minus 8 should be minus 16.
--HG--
extra : convert_revision : 648f01e9753e28391fc8d282bd9fe2bd47a0193f