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Re: [again] switch() statements on ARM/Thumb
- From: Philip Blundell <pb at nexus dot co dot uk>
- To: Richard dot Earnshaw at arm dot com
- Cc: Adrian von Bidder <avbidder at acter dot ch>, gcc-patches <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 10 Jan 2002 15:55:23 +0000
- Subject: Re: [again] switch() statements on ARM/Thumb
- References: <200201101523.PAA12580@cam-mail2.cambridge.arm.com>
>Does linux support using swi 0 in thumb code as meaning something like
>- SWI code is now in r0
>- Other arguments are shuffled down one register.
Linux never looks at the SWI comment field in thumb code. It expects the
system call number in R7 or some similarly high register, and args in R0
upwards as normal.
Adrian is targeting ucLinux, though, which may not be able to cope with
syscalls in Thumb mode at all. I dunno exactly what the current state of
the art is there.
p.