[OpenBIOS] patch that causes a regression with Mac OS X booting

Segher Boessenkool segher at kernel.crashing.org
Mon Dec 14 05:17:55 CET 2015

On Fri, Dec 11, 2015 at 10:31:03AM -0500, Programmingkid wrote:
> > The reason it can't be applied is a little complicated. The MacOS 9
> > bootloader alters the call stack using >r and r> which is illegal
> > outside of a word in Forth - it's like a function changing it's stack
> > pointing and hoping the caller can cope upon return.
> Apple really made something that does that? What were they thinking?
> I can only guess that they didn't like Forth.

It is an extension: they have a separate return stack in interpret mode
(access to this cannot be mixed with R accesses from compiled code).
This is well in line with DO LOOP and other structure words in interpret
mode, which is an OF requirement.

> The <DESCRIPTION> tag looks like this in yaboot (Used by Linux): 
> PowerPC GNU/Linux First Stage Bootstrap

Yaboot does not necessarily use CHRP boot scripts, fwiw.


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