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Re: [PATCH 05/26] arm: Introduce thumb helpers s and pc_ofs
On Tue, 26 Feb 2013, Richard Henderson wrote:
> * sysdeps/arm/sysdep.h (s, pc_ofs): New macros.
Other assembler syntax macros have names in uppercase, and a single
character seems too short for a macro name to me.
> +/* This number is the offset from the pc at the current location. */
> +#ifdef __thumb__
> +# define pc_ofs 4
> +# define pc_ofs 8
As noted, I don't think this can have a conditional definition like this
until .S files are actually built as Thumb.
However, there are existing cases in asm statements with conditionals for
this (sysdeps/unix/sysv/linux/arm/nptl/unwind-resume.c and
sysdeps/unix/sysv/linux/arm/nptl/unwind-forcedunwind.c). So what I'd
actually suggest is defining such a macro for both C and .S code, but
always defining it to 8 for __ASSEMBLER__ at this point and only
conditioning on __thumb__ for C, and making those two C files use the
result of stringizing the macro. Then, when .S files are built as Thumb
the __ASSEMBLER__ conditionals on how to define this macro can be removed.
Joseph S. Myers