Re: [bcc patch] Fix variable offset macros for #asm (was: Re: ELKS memcpy_fromfs() failing. Wrong variable offsets)

[Miguel Bolanos <mike@linuxlabs.com>]

I can't apply this patch either because is for dev86, so will forward it
to Bruce Evans.

thanks

Mike

On Wed, 2004-06-02 at 10:10, Eduardo Pereira Habkost wrote:
> On Wed, Jun 02, 2004 at 09:47:25AM +0100, Robert de Bath wrote:
> <snip>
> > 
> > You have highlighted a bug though, the definition some of the 'set'
> > variables is actually wrong, they should have memcpy_fromfs.off added
> > when it might be non-zero.
> 
> I am sending a fix to this bug. I hope that I didn't anything wrong,
> as I am not familiar with bcc code.
> 
> I guess that creating an outoffset(variable) function that uses
> <function>.off when needed would be better, but that was just a quick fix.
> 
> > 
> > BTW: You should really be using those variables to access C arguments
> > and locals, the '_memcpy_fromfs.ds' is for stack pointer relative the
> > '.memcpy_fromfs.ds' is for 'bp' relative.
> 
> As we have a fix for bcc >= 0.16.8, I will send a fix for ELKS code,
> for using .<function>.<variable>, now.  :)
> 
> > 
> > I can fix the bug in one of two ways; either actually add the
> > 'memcpy_fromfs.off' variable to the 'set' variables or simply
> > have the compiler assume that any '#asm' will use si and di.
> > (The asm("...") function will not however.)
> > 
> > Actually I think assuming that #asm uses si/di is best because as this
> > example has shown it is quite likely to be true, plus, it's the failsafe
> > option.
> 
> I prefer the code as it is now: if some #asm will use some register,
> then it should save it. Or maybe a better one (IMO): having a way to
> tell the compiler which registers will be used.
> 
> And even if assuming that all #asm will use SI and DI, it is a little
> safer fixing the offsets, too. Just in case someone make more changes
> to the code, try to optmize #asm, and break things because there are
> implict things (like: dumplocs() only work because when using #asm,
> <function>.off is zero) they didn't see.
> 
> Which fix do you plan to include on the next releases of bcc?
> 
> (BTW, I really missed a BCC_VERSION macro or equivalent. It would be
> very useful in cases like this one)
> 
> --
> Eduardo
> 
> 
> --- dev86-0.16.15/bcc/codefrag.c	2002-08-03 13:38:27.000000000 -0300
> +++ dev86-current/bcc/codefrag.c	2004-06-02 12:38:28.233060704 -0300
> @@ -105,7 +105,6 @@
>  # define outlswitch() (outload(), outstr(ireg0str), outncregname(DREG))
>  # define outnc1() outnstr(",*1")
>  # define outsbc() outop3str("sbb\t")
> -# define outset() outstr ("\tset\t")
>  # define outsl() outop2str("shl\t")
>  # define outsr() outop2str("sar\t")
>  # define outtransfer() outload()
> @@ -134,6 +133,10 @@
>      outstr(acclostr);
>      outncregname(BREG);
>  }
> +PUBLIC void outset()
> +{
> +    outstr ("\tset\t");
> +}
>  PUBLIC void comment()
>  {
>      outstr("! ");
> @@ -417,7 +420,6 @@
>  # define outpil2switch() outnop2str("LDD\tD,X")
>  # define outrolhi() outnop1str("ROLA");
>  # define outsbc() outop2str("SBC")
> -# define outset() outstr ("\tSET\t")
>  # define outsl() outop1str("LSL")
>  # define outtransfer() outop2str("TFR\t")
>  # define reclaimfactor() outnstr ("++")	/* discard factor from stack */
> @@ -434,6 +436,10 @@
>  # define tfrhilo() outnop2str("TFR\tA,B")
>  # define tfrlohi() outnop2str("TFR\tB,A")
>  # define usr1() (outnop1str("LSRA"), outnop1str("RORB"))
> +PUBLIC void outset()
> +{
> +    outstr ("\tSET\t");
> +}
>  PUBLIC void clrBreg()
>  {
>      outnop1str("CLRB");
> --- dev86-0.16.15/bcc/table.c	2002-07-28 04:43:13.000000000 -0300
> +++ dev86-current/bcc/table.c	2004-06-02 12:48:12.176287840 -0300
> @@ -402,8 +402,38 @@
>  
>      for (i = 0; i < HASHTABSIZE; ++i)
>  	for (symptr = hashtab[i]; symptr != NULL; symptr = symptr->next)
> -	    if (symptr->storage == LOCAL)
> -		set(symptr->name.namea, symptr->offset.offi - sp);
> +	    if (symptr->storage == LOCAL) {
> +		/* Variable offset relative to sp */
> +		outccname(funcname);
> +		outbyte(LOCALSTARTCHAR);
> +		outstr(symptr->name.namea);
> +		outset();
> +		outshex(symptr->offset.offi - sp);
> +		outnl();
> +
> +#ifdef FRAMEPOINTER
> +		/* Variable offset relative to bp */
> +		if (framep) 
> +		{
> +		    outbyte(LOCALSTARTCHAR);
> +		    outstr(funcname);
> +		    outbyte(LOCALSTARTCHAR);
> +		    outstr(symptr->name.namea);
> +		    outset();
> +		    outshex(symptr->offset.offi - framep);
> +#ifdef I8088
> +#ifndef NO_DEL_PUSH
> +		    if (optimise && !callersaves && symptr->offset.offi < framep) {
> +			outbyte('+');
> +			outstr(funcname);
> +			outstr(".off");
> +		    }
> +#endif
> +#endif
> +		    outnl();
> +		}
> +#endif
> +	    }
>  }
>  
>  #ifdef HOLDSTRINGS
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