First, my UNDYING GRATITUDE for porting a recent version of the GNU ARM toolchain to OS X. The holy grail of being able to compile on my primary machine without emulating anything or running a remote desktop is finally within reach! Second, my apologies for asking what must be a stupid question, but I cannot figure out what the line-comment character is in arm-elf-as. The assembler respects # if it occurs BEFORE any source text on a line. It also respects anything enclosed in /* */. But the other typical line-comment characters -- !, ;, |, // -- trigger errors, and even # doesn't work if it occurs after the source content has begin on that line. Not a showstopper of course, but mighty peculiar...? I'm using the toolchain under OS X 10.4.5. Sorry if it's obvious -- I tried changing line-endings to DOS/CRLF & back to UNIX/LF with no difference. Are line comments no longer considered good things? Thanks, --Bill
Found it -- it's the @ character. Though I'm new to the GNU assembler I've used a few others, as well as several macro and scripting languages, and this is the first time I can remember seeing @ used as a line-comment char. I'm curious if there was any rationale for choosing @ over !, #, ;, or //. But not THAT curious. Thanks for reading!
Doh! # is used for immediate operands. Maybe it's time for a vacation.
Bill Burgess wrote: > Found it -- it's the @ character. > > Though I'm new to the GNU assembler I've used a few others, as well as > several macro and scripting languages, and this is the first time I can > remember seeing @ used as a line-comment char. I'm curious if there was > any rationale for choosing @ over !, #, ;, or //. But not THAT curious. > It seems that the delimiter is target specific, presumably in order to conform to the chip manufacturers syntax. However @ is not specified in the manual! The as manual has this to say: http://www.gnu.org/software/binutils/manual/gas-2.9.1/html_mono/as.html#SEC28, it mentions nothing about ARM or @, but under Machine Dependencies, (http://www.gnu.org/software/binutils/manual/gas-2.9.1/html_mono/as.html#SEC155), says that ; is the comment delimiter. Confused? Clifford
Clifford Slocombe wrote: > ...However @ is not specified in the manual! ... Confused? Even more confused than that. The "@" comment delimiter is indeed specified for the ARM architecture in a GNU assembler manual -- but in a version of the manual on Red Hat's web site, not FSF's. From the link, scroll down to section 8.3.2.1 "Special Characters": http://sources.redhat.com/binutils/docs-2.10/as_8.html#SEC163 The Red Hat-hosted manual also lists -marm arguments going up to the 920, while the GNU site's manual only goes up to 8. Evidently the gas manual forked while FSF wasn't looking...?
More time tracking this down...the most recent version of the binutils documentation, last updated in May 2005, appears to be at http://sourceware.org/binutils/docs-2.16/ How do we tell the folks at FSF to quit hosting their obsolete 1994 literature? It's causing more harm than good.
Bill Burgess wrote: > More time tracking this down...the most recent version of the binutils > documentation, last updated in May 2005, appears to be at > > http://sourceware.org/binutils/docs-2.16/ > > How do we tell the folks at FSF to quit hosting their obsolete 1994 > literature? It's causing more harm than good. Thanks for that. I'll update by documentation immediately. Clifford
Bill Burgess wrote:
> http://sourceware.org/binutils/docs-2.16/
Is there a postscript or PDF of this version (or even an HTML tar-ball)
I wonder? - I'd like to have the documentation locally or printable.
Clifford
Clifford Slocombe wrote: > Is there a postscript or PDF of this version ... ? A quick Google for binutils 2.16 texinfo pdf led me here: http://www.delorie.com/djgpp/dl/ofc/current/v2gnu/bnu2161d.zip/ A nice collection of up-to-date PDF, HTML, DVI, and PS-formatted documentation. --Bill
In the WinARM20070505 examples for LPS2378 (maybe others too), Martin Thomas refers to GNU-as manual from binutils V 2.17 (in file crt0.s) for the character @ for the assembler line comments. The same time his old files still use the more common C++ like comments // and it really works with the last version of the Gnu. For me and, maybe many others, the // looks much usual and preferred, than @. Does anybody know why in the referenced manual the // is not mentioned and is it reliable from the future upgrading point of view to use // ? Great thanks in advance, Varuzhan
Varuzhan wrote: > In the WinARM20070505 examples for LPS2378 (maybe others too), Martin > Thomas refers > to GNU-as manual from binutils V 2.17 (in file crt0.s) for the character > @ for the > assembler line comments. > The same time his old files still use the more common C++ like comments > // and it > really works with the last version of the Gnu. > For me and, maybe many others, the // looks much usual and preferred, > than @. Does > anybody know why in the referenced manual the // is not mentioned and is > it reliable from the future upgrading point of view to use // ? The @ is the comment character for the arm-elf-as assembler as already pointed you in the previous messages in this forum-thread. If you'd like to use // and /* */ the C-preprocessor has to parse the source first. Using the preprocessor also offers a lot more options (#if/#ifdef/#include etc.). An assembler source-code gets automatically parsed by the preprocessor if it has the files-extension .S (uppercase S) instead of .s (lowercase s). Also see the documentation on the option -x assembler-with-cpp. There is not special reason why I used the "@-comment" in the LPC2378 examples. As you can see the file extension for the assembler-sources is an uppercase S so // and /* */ can be used too. I just did a "search in replace" to replace the comment-character used in the original NXP example-code with @ (replace by // could have been done too). I don't think there will be any problems with future versions of the toolchain in this field. If you prefer the C-style comments just use them and make sure the preprocessor parses the assembler-source first. Hope this helps, Martin Thomas
Martin Thomas wrote: > Varuzhan wrote: >> In the WinARM20070505 examples for LPS2378 (maybe others too), Martin >> Thomas refers >> to GNU-as manual from binutils V 2.17 (in file crt0.s) for the character >> @ for the >> assembler line comments. >> The same time his old files still use the more common C++ like comments >> // and it >> really works with the last version of the Gnu. >> For me and, maybe many others, the // looks much usual and preferred, >> than @. Does >> anybody know why in the referenced manual the // is not mentioned and is >> it reliable from the future upgrading point of view to use // ? > > The @ is the comment character for the arm-elf-as assembler as already > pointed you in the previous messages in this forum-thread. If you'd like > to use // and /* */ the C-preprocessor has to parse the source first. > Using the preprocessor also offers a lot more options > (#if/#ifdef/#include etc.). An assembler source-code gets automatically > parsed by the preprocessor if it has the files-extension .S (uppercase > S) instead of .s (lowercase s). Also see the documentation on the option > -x assembler-with-cpp. > > There is not special reason why I used the "@-comment" in the LPC2378 > examples. As you can see the file extension for the assembler-sources is > an uppercase S so // and /* */ can be used too. I just did a "search in > replace" to replace the comment-character used in the original NXP > example-code with @ (replace by // could have been done too). > > I don't think there will be any problems with future versions of the > toolchain in this field. If you prefer the C-style comments just use > them and make sure the preprocessor parses the assembler-source first. > > Hope this helps, > Martin Thomas Dear Thomas, Thank you very much, you make a really great work with the WinARM and great support, much better than commercial. Varuzhan
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