Anyone know how to cure the message:
/usr/src/linux-2.3.47/include/linux/fs.h:769: warning: implicit declaration of function `abs'
in the 2.3.47 build?
abs is #defined in stdlib.h but I'm not sure that's used in the kernel builds.
(did I miss some patches?)
-brad
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On Sat, 26 Feb 2000, Brad Parker wrote:
Anyone know how to cure the message:
/usr/src/linux-2.3.47/include/linux/fs.h:769: warning: implicit declaration of function `abs'
in the 2.3.47 build?
abs is #defined in stdlib.h but I'm not sure that's used in the kernel builds.
Personnaly I have since long appended -Dabs=__builtin_abs to the compiler
flags parameter in arch/ppc/Makefile and removed it the ppc_ksyms.c and
the corresponding assembly code. There may be broken builtins in the
compiler (I did not try to remove the -fno-builtins) but the abs builtin
certainly works and is much better when inlined and scheduled by the
compiler. Calling a subroutine for such a simple function is ridiculous
and expensive especially from a module where you go through an indirect
jump in the procedure linkage table. Besides the compiler's implementation
is smarter and does not even require a conditional branch.
Gabriel.
(did I miss some patches?)
-brad
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