inline asm bug

[brodsom]

Simen Kjaeraas Wrote:

> Blas Rodriguez Somoza <blas at puertareal.com> wrote:
> 
> > Hello
> >
> > I've found something that seems to a bug working with the inline  
> > assembler, but I'm not sure if it is the expected behavoir.
> >
> > The reference to struct/unions don't work if there is nested  
> > structs/unions defined separately. Example:
> >
> > union test {
> > 	ulong var1;
> > 	struct var2 {
> > 		ubyte zz;
> > 	}
> > }
> >
> > union test2 {
> > 	ulong var1;
> > 	pp var2;	
> > }
> >
> > struct pp {
> > 	ubyte zz;
> > }
> >
> > ..
> > ..
> > asm{
> > 	..
> > 	movzx EAX, test.var2.zz[ESI];
> > 	movzx EAX, test2.var2.zz[ESI];
> > 	..
> > }
> >
> > The first line succeed but the second fails:
> >
> > Error: need 'this' for address of var2
> > Error: need 'this' for address of var2
> > bad type/size of operands '*(& var2)'
> >
> > When, by error, I change the second line to
> >
> > 	movzx EAX, test2.var2->zz[ESI];
> >
> > the compiler crash.
> >
> >
> > Regards
> > Blas Rodriguez Somoza
> 
> To me it seems you are referencing the struct definitions/prototypes, not  
> a struct instance. Try something like this:
> 
> 
> union test {
> 	ulong var1;
> 	struct var2 {
> 		ubyte zz;
> 	}
> }
> 
> union test2 {
> 	ulong var1;
> 	pp var2;	
> }
> 
> struct pp {
> 	ubyte zz;
> }
> 
> test foo; // new lines here
> test2 bar;
> 
> ..
> ..
> 
> asm{
> 	..
> 	movzx EAX, foo.var2.zz[ESI];
> 	movzx EAX, bar.var2.zz[ESI];
> 	..
> }
> 
> Simen Kjaeraas

In inline assembler this kind of reference must be to a struct/union definition. It means an offset from the address contained in the register.