From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jan Hubicka <jh@suse.cz>
To: Joern Rennecke <amylaar@cygnus.co.uk>
Cc: gcc@gcc.gnu.org
Subject: Re: SUBREGs and modes
Date: Wed, 02 Aug 2000 08:49:00 -0000
Message-id: <20000802174932.A20604@atrey.karlin.mff.cuni.cz>
References: <20000802144916.L22797@atrey.karlin.mff.cuni.cz> <200008021539.QAA25092@phal.cygnus.co.uk>
X-SW-Source: 2000-08/msg00028.html

> > weird usage of SUBREGs. According to my uderstanding the docs, when
> > WORDNUM is nonzero, the  innermode must be greater than word and
> > the outer mode must be word.
> 
> Where does it say that the outer mode must be word?
The other use of @code{subreg} is to extract the individual registers of
a multi-register value.  Machine modes such as @code{DImode} and
@code{TImode} can indicate values longer than a word, values which
usually require two or more consecutive registers.  To access one of the
registers, use a @code{subreg} with mode @code{SImode} and a
@var{wordnum} that says which register. 

Actually speaks about SImode, but is interpreted in the code as
word.

Honza