On Thu, 7 May 1998 kim@pvv.ntnu.no wrote:

> > If you mean `modify the linker so it _does_ page align everything', that would 
> > cause tremendous code bloat.  For example, the GNU C library contains 1076 
> > object files.  Assuming that, on average, you'd waste half a page per object 
> > by aligning them, that would cost you a total of over 2MB.  In fact it's even 
> > worse than that because a significant number of them are much smaller than a 
> > single page - they only contain a few hundred bytes of code.  So again, it's 
> > possible, but you have to weigh up whether it's actually worth the cost.  If 
> > you _did_ do this, you would either have to maintain two versions of 
> > everything, or foist this wastage of space onto everybody who uses NetBSD, the 
> > majority of whom probably don't have CPUs with this problem.
> 
> Then don't page align the code. Just let the linker put a NOP at the
> end of each page.
> 
> This of course puts NOPs in the middle of the code, but the linker should
> be able to handle that, since it must contain references to branches
> and indexes. I don't know how this apply to PIC code though.
> 
> Km0
> 

Erm, the linker doesn't page align, so it cant put a nop at the end of the
page.  If the extra nops are in the middle of the pages, then it doesn't
stop STM^ ' s from ending up on page boundries.

Oli

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