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Re: [avr-gcc-list] Using X and Z register in global variables
From: |
Joerg Wunsch |
Subject: |
Re: [avr-gcc-list] Using X and Z register in global variables |
Date: |
Sun, 4 Sep 2005 21:00:39 +0200 |
User-agent: |
Mutt/1.4.2.1i |
As User Tomdean wrote:
> This is warning about using Z and X, but, not Y.
Maybe you could really use Y as a global reg variable, but I'd rather
avoid that. It severely restricts the compilers freedom of choice to
generate decent code for the remaining program. If you're linking
against avr-libc, you're also *heavily* at risk that some library code
(not knowing about your choice of a global register variable) clobbers
it.
> But, I could not get gcc to use Z+.
I think nobody taught GCC to use it, except perhaps in a few
fixed-pattern situations.
--
cheers, J"org .-.-. --... ...-- -.. . DL8DTL
http://www.sax.de/~joerg/ NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)