sysexit
sysenter assembly
asm sysenter
sysenter vs int 0x80
sysenter vs syscall
syscall instruction
syscall/sysretsysenter linux

Executes a fast call to a level 0 system procedure or routine. SYSENTER is a companion instruction to SYSEXIT. The instruction is optimized to provide the Executes a fast call to a level 0 system procedure or routine. SYSENTER is a companion instruction to SYSEXIT. The instruction is optimized to provide theThe SYSENTER instruction is part of the "Fast System Call" facility introduced on the Pentium(R) II processor. The SYSENTER instruction is optimized to The SYSENTER instruction is part of the "Fast System Call" facility introduced on the Pentium® II processor. The SYSENTER instruction is optimized to Windows XP introduced support for the SYSENTER instruction as a fast way to ring 0 and SYSEXIT as a fast way back to ring 3.