[SeaBIOS] [PATCH 1/2] vgabios: Add config option for assembler fixups

[Peter Stuge]

Kevin O'Connor wrote:
> > > +++ b/vgasrc/vgaentry.S
> > > @@ -64,6 +64,7 @@ x86emu_fault:
> > >          // This macro implements a call while avoiding instructions
> > >          // that old versions of x86emu have problems with.
> > >          .macro VGA_CALLL cfunc
> > > +#if CONFIG_VGA_FIXUP_ASM
> > >          // Make sure leal instruction works.
> > 
> > Isn't the logic backwards here?
> 
> Are you pointing out the trap only being enabled when
> CONFIG_VGA_FIXUP_ASM is on?

Right.


> The trap is only useful if doing asm fixups

Isn't that backwards? The trap is most important if *not* doing fixups?

(Because then the generated binary may have known problems. Trapping
them in that case would be nice.)


> as some x86emu versions do support leal, but will silently
> crash on other instructions (such as calll).

In case the trap is important also when doing fixups, why not just
always enable it?


> I only expect CONFIG_VGA_FIXUP_ASM to be off for those debugging
> something.

If you say so.. But the always-on trap was helpful in this case.


//Peter