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Re: [DOC PATCH] Rewrite docs for inline asm


On 29/04/14 11:47, dw wrote:
> While I'm waiting to hear back from Gerald about my responses to his 
> other corrections, I have answered one question:
> 
>> How does the user know what is dialect #0?  Same for the others?
>>
>> When I originally wrote that section, I didn't know the answer (which 
>> is why I left it vague).  Now I think I do, but I'd like someone to 
>> confirm.  On my builds of gcc, the dialects are listed (in dialect 
>> order) under "Known assembler dialects" in "gcc --target-help".  Can I 
>> rely on this enough to put it in the docs? Is there some better source?
> 
> First of all, -masm is (currently) only supported on i386: 
> http://gcc.gnu.org/onlinedocs/gcc/Option-Summary.html
> 
> Second, i386 -masm only supports two options: 
> http://gcc.gnu.org/onlinedocs/gcc/i386-and-x86-64-Options.html
> 
> So, the inline asm docs could just say "att" and "intel."  However, 
> there's a difference between using "intel" and "att" as examples of how 
> dialects work, and "hard coding" these names into this section as the 
> list of available options.  I'm not keen on putting machine-specific 
> info like this into an otherwise machine-neutral section.
> 
> Such being the case, I replaced the previously vague paragraph with:
> 
> GCC may support multiple assembler dialects (such as "att" or "intel") for

It's generally wise to avoid 'may' in documentation; in this case I
think 'can' is acceptable.

Also, you should be clear at the time you introduce att and intel that
you are referring to the i386 compiler.  Something like: "(for example,
GCC for i386 supports "att" and "intel" dialects)".

R.

> inline assembler. In builds that support this capability, the 
> @option{-masm}
> option controls which dialect GCC uses as its default. The 
> hardware-specific
> documentation for the @option{-masm} option contains the list of supported
> dialects, as well as the default dialect if the option is not specified. 
> This
> information may be important to understand, since assembler code that works
> correctly when compiled using one dialect will likely fail if compiled 
> using
> another.
> 
> This keeps the machine-specific details with the already 
> machine-specific compile options.  While this option only applies to 
> i386 currently, this text leaves the option open should some other 
> platform make use of it in the future.
> 
> Unless someone says otherwise, I'm calling this question resolved.
> 
> dw
> 



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