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Conference vaxaxp::vmsnotes

Title:	VAX and Alpha VMS
Notice:	This is a new VMSnotes, please read note 2.1
Moderator:	VAXAXP::BERNARDO

Created:	Wed Jan 22 1997
Last Modified:	Fri Jun 06 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	703
Total number of notes:	3722

457.0. "Counting procedure parameters" by SAONE::POMMIER_JC () Mon Apr 14 1997 04:27

   Hi ,

        I have a customer which is using the following 
        macro procedure ( on VAX ) to count the number of
        parameters given to a procedure ( written in fortran,
        basic,C ):

               MOVL 8(FP),R0

         As this structure doesn't exist any more on Alpha,
         is there any way to do it on an Alpha system ?

         Many thanks in advance for any help

            Jean-Claude

T.R	Title	User	Personal Name	Date	Lines
457.1		AUSS::GARSON	DECcharity Program Office	`Mon Apr 14 1997 04:31`	7
	re .0 That approach simply won't work on Alpha. You should use the built-in function appropriate to the language you are using. FORTRAN and C both have one. I don't know about BASIC. Try the BASIC conference. Note that obtaining the argument count is probably non-standard and non-portable in most languages.
457.2	IARGCOUNT ?	MUCTEC::BECKER	Hartmut B., VMS & Languages, Munich	`Mon Apr 14 1997 08:47`	6
	Looks like IARGCOUNT can do the job. Help Fortran Intrinsic Iargcount explains: A function that returns the count of actual arguments passed to the current routine. Hth, Hartmut
457.3	Pointers...	XDELTA::HOFFMAN	Steve, OpenVMS Engineering	`Mon Apr 14 1997 10:28`	16
	There is a Macro32 (VAX Aseembler, Alpha Compiler) conference at TURRIS::MACRO. You will want to point the customer at the Porting Macro32 documentation in the OpenVMS documentation set, as well. You will also want to point your customer at the LIB$ routines that look at the "invocation" construct. And you will want to point your customer -- in addition to the Fortran keyword in a previous reply -- at the C variable-length argument processing, which also includes a mechanism by which the argument count can be retrieved. (Donno about BASIC, ask the folks over in the BASIC conference.)
457.4	GET_INVO_XXX not useful for this stuff	WIBBIN::NOYCE	Pulling weeds, pickin' stones	`Mon Apr 14 1997 10:51`	7
	> You will also want to point your customer at the LIB$ routines > that look at the "invocation" construct. No, that won't be useful for finding the number of arguments a caller received. The only reliable method on Alpha is to use the language's builtin argument-count operator or function. If BASIC doesn't have one, then there's no reliable method for BASIC.
457.5	It's The Alpha "Call-Frame Traversal" Code...	XDELTA::HOFFMAN	Steve, OpenVMS Engineering	`Mon Apr 14 1997 12:06`	8
	:> You will also want to point your customer at the LIB$ routines :> that look at the "invocation" construct. : :No, that won't be useful for finding the number of arguments a caller :received. But it is the closest Alpha mechanism available "comparable" to the VAX call-frame traversal scheme...
457.6		TLE::REAGAN	All of this chaos makes perfect sense	`Mon Apr 14 1997 13:52`	6
	Yes you can find the caller's frame. But since the compiler is at liberty to move the argument count to anywhere (or throw it away altogether if it doesn't appear to be needed), you can't reliably find the argument count even if you have the frame pointer. -John