Re: [ft-devel] Experimental: v38 interpreter with minimal backwards compatibility mode and linear advance widths

[Nikolaus Waxweiler]

> Mhmm.  This is too hars harsh.  I would rather simply stop
> interpretation of delta instructions but let everything else work.
> For example, IUP[xy] could be called within conditionals, and it would
> be bad if the following `EIF' doesn't get interpreted, causing
> unwarranted execution failures.

Or, how about doing

  if ( exc->backwards_compatibility && exc->iupx_called && 
exc->iupy_called )
    goto LNo_Error_;

at the top of the instruction execution loop? Just pretend everything is 
okay?

I mean, is there any point in continuing if DELTAP/SHPIXes are denied 
anyway? That would also save a few backwards-compatibility-ifs and 
probably yield a tiny performance boost on core web fonts, a nice 
selling point for a Phoronix article ;)

Or is there anything else that can cause execution failures? Any 
clean-up that would need to be done?