[OpenBIOS] Even more findings to report about booting Mac OS 9

[Programmingkid]

On Apr 16, 2016, at 9:52 PM, Segher Boessenkool wrote:

> On Sat, Apr 16, 2016 at 09:40:04PM -0400, Tarl Neustaedter wrote:
>> On 2016-Apr-16 21:14 , Segher Boessenkool wrote:
>>>>> One possible solution; take the boot-script code, and rather than
>>>>> interpret it directly, try compiling it.
>>> That does not work.  The OS9 bootscript contains many definitions as well.
>>> Not just colon definitions.
>> 
>> I thought the other definitions should work inside a colon definition.
>> Unfortunately, I no longer have access to an openboot to test against (I
>> retired late last year).
> 
> A trivial example is
> 
> 1000 constant pagesz
> pagesz 1- constant pagesz-1
> 
> If you put that inside a colon def, the second pagesz will error when
> the colon def is compiled (the word hasn't been defined yet).
> 
>>> In summary, the two things you need:
>>> 
>>> -- Parse the bootscript line by line.
>>> -- Have a separate interpretation mode R stack.
>>> 
>> 
>> The separate R stack is probably the harder issue.
> 
> It isn't hard to implement /an sich/.  Both Apple OF and OFW (and thus,
> openboot) already have it.  It will however uncover shortcomings in
> your text interpreter :-/

Apple already has this? Would you have an example program that would work in Apple's OF that would not work in OpenBIOS when using the return stack?