Subject: Re: RFC: Change SWI number base?
To: None <port-arm@netbsd.org>
From: John Tytgat <John.Tytgat@barco.com>
List: port-arm
Date: 01/04/2002 13:18:36
Ben Harris wrote:
>Why? What's wrong with keeping the ARM veneers as they are, and just
>making the Thumb veneers indirect through SYS_syscall when they need to
>(or even all the time, which would make SYS.h easier to write).
>
>Remember, using SYS_syscall all the time will change a typical veneer
>from:
>
> swi SYS_foo
> bcs __cerror
> mov pc, lr
>
>to:
>
> str r3, [sp, #-4]!
> mov r3, r2
> mov r2, r1
> mov r1, r0
> mov r0, #SYS_foo
> swi SYS_syscall
> bcs __cerror
> mov pc, lr
>
It's even worse, you need to restore the sp stack on exit too.
John.
--
John Tytgat f u cn rd ths,
John.Tytgat@barco.com u cn gt a gd jb n cmptr prgrmmng !