Subject:
Re: some question about the directive GLOBAL in the source code.
From:
Tamas Rudnai ####@####.####
Date:
17 Aug 2012 07:12:09 -0000
Message-Id: <CAJLb5+R-ueNq4HXk0phGh1Ln2VM=xKe3uGXbbsSqEcW0+kK4vg@mail.gmail.com>
No worries with your English :-) So you mean must be processed by the
assembler (compiler), right?
I think I got you. Are you claiming that the compiler is not working
properly and when a 'global' directive is used before declaring the
variable, it should create the symbol in the symbol table as opposed to
return with 'no symbol' ? In this case I think you are right.
How it works in gpuitls -- I do not know, I have not looked at the source
code yet. Hope someone is seeing this who does and can help you with
debugging the compiler's source.
Tamas
On 16 August 2012 23:24, feqin fan ####@####.#### wrote:
> My english writing is poor, Maybe it misled you, Sorry , It’s my fault.
>
>
>
> I’m here discussing the assembler source code’s behavior, Not CPU’s
> behavior.
>
> the directive “global var” must be executed by assembler.
>
> and in line 5,the function maybe_evaluate_concat() does not to query symbol
> table, it just do some macro process, and must be return the string “var”.
>
>
> Thanks for you letter..
>
> :-)
>
>
>
> 2012/8/17 Tamas Rudnai ####@####.####
>
> > The "global var" will never be "executed" as that is not an instruction
> but
> > a directive. But that is not important right now.
> >
> > What is important that although I have never looked at the full source
> code
> > and therefore not sure what are those functions and macros doing there,
> but
> > following your logic in the comments, the "p will point to var" in line
> 5.
> > Now if var is unknown at that stage, then maybe p will be NULL, right? So
> > because of the condition at line 6, the compiler will never make it to
> the
> > line 7... Just my cents.
> >
> > Tamas
> >
> >
> >
> > On 15 August 2012 19:50, feqin fan ####@####.#### wrote:
> >
> > > because the symbol_table stTop have nothing about symbol "var", the
> > source
> > > line "global var" is first line executed by assembler.
> > >
> > > all of this are my inferences.
> > >
> > > :-)
> > >
> > > THX..
> > >
> > > 2012/8/16 Holger Oehm ####@####.####
> > >
> > > > -----BEGIN PGP SIGNED MESSAGE-----
> > > > Hash: SHA1
> > > >
> > > > On 14.08.2012 12:35, feqin fan wrote:
> > > > > Hello, everybody, I'm sorry to trouble you again.
> > > > > I have read most of the source code of gputils. I have a query
> > > about
> > > > > the implementation of the directive GLOBAL.
> > > > > for example, Have this code:
> > > > >
> > > > > global var
> > > > >
> > > > > udata
> > > > > var res 1
> > > > >
> > > > > the assembler deal with the first line "global var",
> > > > > the calling sequence is like this : yyparse() -
> > do_or_append_insn(char
> > > *,
> > > > > struct pnode *) - do_insn(char *, struct pnode *) - do_global()
> > > > > the function do_global() source code :
> > > > >
> > > > > 1, if (state.mode == absolute) {
> > > > > 2, gperror(GPE_OBJECT_ONLY, NULL);
> > > > > 3, } else {
> > > > > 4, for (; parms; parms = TAIL(parms)) {
> > > > > 5, p = maybe_evaluate_concat(HEAD(parms)); //p will
> > point
> > > > to
> > > > > "var".
> > > > > 6, if (p) {
> > > > > 7, s = get_symbol(state.stTop, p); //s will be NULL
> > > > > 8, if (s == NULL) {
> > > > > 9, snprintf(buf,
> > > > > 10, sizeof(buf),
> > > > > 11 "Symbol not previously defined (%s).",
> > > > > 12, p);
> > > > > 13, gperror(GPE_NOSYM, buf);
> > > > >
> > > > >
> > > > >
> > > > > the line 4 must be first executed, in line 5 the p will point to
> > "var".
> > > > and
> > > > > in line 7, because the source code "global var" is the first line
> of
> > > the
> > > > > being assembled code.
> > > > > So. in the function do_global() line 7, the s will be NULL,
> > > >
> > > > And why exactly should s be NULL after the assignment in line 7???
> > > > -----BEGIN PGP SIGNATURE-----
> > > > Version: GnuPG v1.4.11 (GNU/Linux)
> > > > Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/
> > > >
> > > > iEYEARECAAYFAlAr48sACgkQHdk+97UOUanAAgCfYSdqul+vqfA3ARzB38GScQGT
> > > > 8lUAoIVHttJ6BOx1WLJCph25B4ak3+dN
> > > > =N8FO
> > > > -----END PGP SIGNATURE-----
> > > >
> > > > ---------------------------------------------------------------------
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> > > >
> > > >
> > >
> >
> >
> >
> > --
> > int main() { char *a,*s,*q; printf(s="int main() { char *a,*s,*q;
> > printf(s=%s%s%s, q=%s%s%s%s,s,q,q,a=%s%s%s%s,q,q,q,a,a,q); }",
> > q="\"",s,q,q,a="\\",q,q,q,a,a,q); }
> >
>
--
int main() { char *a,*s,*q; printf(s="int main() { char *a,*s,*q;
printf(s=%s%s%s, q=%s%s%s%s,s,q,q,a=%s%s%s%s,q,q,q,a,a,q); }",
q="\"",s,q,q,a="\\",q,q,q,a,a,q); }
