Re: New SYSCALL instruction (was: Re: Call Gates)

Alan Cox (
Fri, 20 Jun 1997 23:29:56 +0100 (BST)

> All newer pentiums & pro's, and the K5 and K6 have the newer SYSCALL/SYSRET
> instructions: 2 byte opcode, and upon entry to the system only cs and the stack
> are reloaded. This is very fast :-) Anyone looking into implementing this as
> an alternative to int $80 in the linux kernel? A lot of syscalls can do without
> to much protection :-)
> btw, this instructions are described in detail in the K6 databook...

Interesting to note they dont appear in the Intel PPro databook. So either
its an AMD special or Intel are pulling appendix-H type games again