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ARM r12 usage
- To: gcc at gcc dot gnu dot org
- Subject: ARM r12 usage
- From: "Andre" <armcc at lycos dot com>
- Date: Fri, 09 Mar 2001 07:51:58 -0800
- Organization: Lycos Mail (http://mail.lycos.com:80)
- Reply-To: armcc at lycos dot com
The Description of the ARM Procedure Call Standard in "ARM System Architecture" by Steve Furber, seems to say that r12 can be used as a scratch register within a function without preserving the callers contents.
However, a few brief tests with arm-linux-gcc v2.95.2 seem to save show that the callers r12 is saved on the stack before the register is used.
Which is correct ??
Is it safe to write assembler functions which don't save r12 (and call them from C compiled with both gcc and armcc) ?? Or will things eventually all go horribly wrong if I don't save r12 ?? :-)
Thanks
Andre
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