#113 Add support for binary constants v2
Hello everybody,
the attached is my new attempt to bring binary constants to sdcc. Not that this single feature deserves all this work, but since I started...
The series is compound by 4 patches, plus the documentation updates. A brief description follows.
*** 1-use-correct-std-making-lib.patch
This is a bugfix patch. Some device libraries were built with --std-c89, but the code included c++ comments (//). Moreover, CFLAGS got lost for PIC14 when building libdev. This patch ensures that libraries using C99 features are actually built using --std-c99, and fixes the PIC14 issue.
*** 2-sdcpp-implement-sdcc-extensions-framework.patch
This patch makes the preprocessor accept -std=sdcc89 and -std=sdcc99. The effect is limited to enabling the GNU extensions.
Note that to retain some backwards compatibility we should at least enable c++ comments with --std-sdcc89, otherwise a lot of user code will be suddendly broken.
*** 3-sdcc-call-sdcpp-with-correct-std.patch
This patch makes sure sdcpp gets called with the correct -sdc=xxx switch
*** 4-sdcc-implement-binary-constants.patch
This patch finally implements binary constants. Now these are enabled only with -std-sdccxx and I also propagated the changes to the preprocessor.
One note on this: apparently I'm too dumb to understand why the preprocessor cares about constant parsing, and I haven't been able to actually test the code. Note also that even before this patch the preprocessor parsed binary constants in #if tests, regardless of the -std switch.
For what relates the documentation, the source document was written with a relatively old LyX version (1.4.5). Editing it with the latest version (1.5.6) generates a huge diff, and is probably unwanted anyway due to the bump in the required LyX version.
Since I found that the modifications required by this patch series are small, it's probably more efficient to simply ask somebody else using LyX 1.4 to apply them for me ;-)
The changes are:
In section 1.4, add the following to the list:
* in older versions, the preprocessor was always called with -std=c99 regardless of the --std-xxx setting. This is no longer true, and can cause compilation failures on code built with --std-c89 but using c99 preprocessor features, such as one-line (//) comments.
Insert a new section between 3.4 and 3.5, containing the following:
3.5 Other SDCC language extensions
3.5.1 Binary constants
SDCC supports the use of binary constants, such as 0b01100010. This feature is only enabled when the compiler is invoked using --std-sdccxx.
3.5.2 Preprocessor
When invoked with --std-sdccxx, the preprocessor uses the GNU cpp extensions.
This series applies to revision 5202. Please review this carefully before applying since I touched so many parts of the compiler I could very well have done some mistakes.
Mauro
Patch series implementing binary constants
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Mauro,
is it really necessary to introduce -std=sdccXX options to sdcpp? Aren't they equal to GNUC extensions, so that in case of --std-sdccXX sdcc would call sdcpp without -std=XXXX option?
And I think that binary_constants is not needed:
if (CLK_GNUC89 == CPP_OPTION (pfile, lang) || CLK_GNUC99 == CPP_OPTION (pfile, lang))
could be used instead. This is actually a bug in the current sdcpp implementation, since the binary constants are not accepted if -pedantic-parse-number is defined and gcc extensions are enabled.
If I'm right then we have just to fix a bug in sdcpp and nothing more, since sdcpp already supports binary constants.
I already prepared the patched version. Just let me know if I missed something...
> One note on this: apparently I'm too dumb to understand why the
> preprocessor cares about constant parsing
see http://sourceforge.net/tracker/index.php?func=detail&aid=982435&group_id=599&atid=100599
Borut
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Hello Borut,
thank you for taking the time for reviewing that mess.
> is it really necessary to introduce -std=sdccXX options to sdcpp? Aren't
> they equal to GNUC extensions, so that in case of --std-sdccXX sdcc would
> call sdcpp without -std=XXXX option?
I don't know what's the sdcpp's behavior when called without -std. Well, I haven't looked. My fault.
Nevertheless I thought that having some sort of parallelism between sdcc's --std-xxxx and sdcpp's -std=xxxx would be a good idea anyway.
If you tell me that sdcpp's behavior without -std is a superset of C99, then I'm fine about omitting -std when the compiler is called with --std-sdccxx, and only specifying it as c89 or c99 when the compiler is called with --std-cx9.
> And I think that binary_constants is not needed:
>
> if (CLK_GNUC89 == CPP_OPTION (pfile, lang) || CLK_GNUC99 == CPP_OPTION
> (pfile, lang))
>
> could be used instead. This is actually a bug in the current sdcpp
> implementation, since the binary constants are not accepted if
> -pedantic-parse-number is defined and gcc extensions are enabled.
That's fine. Some part of my brain hadn't realized that binary constants are part of the GCC extensions.
> I already prepared the patched version. Just let me know if I missed
> something...
I didn't see your modified patches anywhere, so I'm going to guess.
We're talking about modifying the patches 2, 3 and 4 this way:
- patch 2 is removed;
- in patch 3 {cppstd} now includes "-std=", and is set only when options.std_sdcc is not
set;
- in patch 4, binary_constants and all its management are removed, and the condition in
lex.c@662 becomes the one you proposed (quoted ~17 lines above).
Well, that's far smaller than my version ;-).
Your proposal works fine as far as I can tell, so you have my approval.
Also, thank you for the link. I was dumb, indeed.
> Borut
Mauro
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Hi Mauro,
> I don't know what's the sdcpp's behavior when called without -std.
Is the same as gcc cpp's: gcc extensions are enabled by default.
> Nevertheless I thought that having some sort of parallelism between sdcc's
> --std-xxxx and sdcpp's -std=xxxx would be a good idea anyway.
I try to keep sdcc specifics in sdcpp (gcc cpp) as low as possible. Since binary constants are already supported, there is no need to introduce -sdcc=sdccXX options.
>> if (CLK_GNUC89 == CPP_OPTION (pfile, lang) || CLK_GNUC99 == CPP_OPTION
>> (pfile, lang))
Even better solution:
if (!CPP_OPTION (pfile, std))
> I didn't see your modified patches anywhere, so I'm going to guess.
They are on may local svn snapshot and you guess is correct.
> Also, thank you for the link. I was dumb, indeed.
In contrary: I would think that you are a genius if you wold foreseen the problem mentioned in the link ;-)
Modified patch applied in svn revision #5205.
Borut