[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [avr-gcc-list] __zero_reg__
From: |
Joerg Wunsch |
Subject: |
Re: [avr-gcc-list] __zero_reg__ |
Date: |
Sun, 22 Feb 2004 21:24:52 +0100 (MET) |
As Anich Gregor <address@hidden> wrote:
>When the program is interrupted it is absolutely possible that the
>zero-reg is not zero at this time because it is defined to be zero
>whenever a C function is called - you can do with it whatever you
>want to as long as you make sure that you set it to zero again before
>giving control back to compiler-generated code because it depends on
>that ;)
The biggest problem is that zero_reg as r0 is a poor choice because it
can be clobbered by the hardware multiplication result in the ATmega.
(IMHO, this detail has been unknown to the AVR-GCC developers by the
time they've chosen about zero_reg.)
--
J"org Wunsch Unix support engineer
address@hidden http://www.interface-systems.de/~j/
_______________________________________________
avr-gcc-list mailing list
address@hidden
http://www.avr1.org/mailman/listinfo/avr-gcc-list