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AW: AW: [avr-gcc-list] Double desirability

From: Haase Bjoern (PT-BEU/EMT) *
Subject: AW: AW: [avr-gcc-list] Double desirability
Date: Fri, 8 Apr 2005 11:15:13 +0200

Joerg Wunsch wrote
>>The FP basics are already implemented inside GCC right now.  I didn't
>>look how it's done, I assume it's just compiled into libgcc.a, using
>>GCC's generic code (which is IMHO semi-automatically generated C
>The fplib part of avr-libc only affects standard functions (like the
>trigonometrical functions etc).

I just had a look at the 3.4.3 sources: Not even fp-add and fp-multiply are 
defined in gcc's own stdlib. Ist all in avr-libc's libm. It might be that gcc 
itself has a FP emulation library in libgcc2 written in plain C but probably 
this one is really inefficient since it needs to be target-independent.

>> This would also resolve the bug, that
>> fp support is broken when forgetting to link with -lm.
>We (the avr-libc developers) already basically agreed that libm.a is
>scheduled to disappear in the long run.  The division into libc.a and
>libm.a probably made some sense on the PDP-11, but it makes no sense
>at all in avr-libc, in particular given that some functions declared
>in <stdlib.h> are actually being implemented in libm.a.
>In order to not break old Makefiles, we'll probably ship a dummy
>libm.a then.

I thinkt that this is a good idea.

>My intention is to make this move when we finally adopted a scheme to
>go for per-device libraries.

Would be *much* appreciated  :-).



J"org Wunsch                                           Unix support engineer
address@hidden        http://www.interface-systems.de/~j/

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