SYSCALL invokes an OS system-call handler at privilege level 0. It does so by ***loading RIP from the IA32_LSTAR MSR*** (after saving the address of the instruction following SYSCALL into RCX). (The WRMSR instruction ensures that the IA32_LSTAR MSR always contain a canonical address.)
SYSCALL invokes an OS system-call handler at privilege level 0. It does so by ***loading RIP from the IA32_LSTAR MSR*** (after saving the address of the instruction following SYSCALL into RCX). (The WRMSR instruction ensures that the IA32_LSTAR MSR always contain a canonical address.)