[OpenBIOS] Current finding on booting Mac OS 9.2

[Programmingkid]

On Apr 21, 2016, at 1:17 PM, Segher Boessenkool wrote:

> On Thu, Apr 21, 2016 at 12:26:06PM -0400, Programmingkid wrote:
>> As Segher had suggested, I executed the boot script one line at a time. This enabled me to see what line failed. The line that is failing is this:
>> 
>> r> here - allot
>> 
>> The message printed after this line is executed is:
>> 
>> "Dictionary space overflow: dicthead=000c3fe4 dictlimit=00080000"
>> 
>> So I decide to find out what value was being allot'ed. Using this code:
>> 
>> r> here - dup ." Calling allot with " . cr allot
>> 
>> The value that is being allocated is 0xa43ef or 672,751. Just for a comparison, I tried my code on Apple's Open Firmware. The value it allocates is 0xffffffd7. So I think the solution might be to increase available memory to OpenBIOS's dictionary.
> 
> [ L O O O O N G  L I N E S ]
> 
> No, the solution is to make R> work in interpret mode.  Properly.

Wouldn't we be better off avoiding using R> and >R? Apple's code
looks like it only cares about using the return stack as a
placeholder for data (correct me if I am wrong on this point).
Tarl said if the parsing code uses the return stack, then this
boot script would mess it up. So it seems avoiding using the
return stack is a logical course of action.

I did try your version of r> and >r. The end result was pretty
much the same as my patch. The "Dictionary Space overflow"
error message is still printed. This doesn't mean you are wrong,
it just means maybe there is more that needs fixing.

> And you'll need structure words to work as well.  Piling workarounds
> on top of workarounds won't get you far.

I remember your list of words that you thought had problems:

AHEAD IF THEN  BEGIN AGAIN UNTIL  CASE ENDCASE  DO ?DO LOOP +LOOP

What makes you so sure it is these words that are the problem?

My test for BEGIN AGAIN in interpret mode:
begin
." hello world"
again

The result was "hello world" being printed over and over
again. It seems to work in interpret mode. 

The IF tests:

0 if ." false" else ." true" then

1 if ." true" else ." false" then

Both these tests print "true" like they are suppose to.

The do loop test:

decimal
100 0 do
    ." number: " i . cr
loop

The output is the expected list of numbers.
number 0 
number 1 
number 2 
...
number 99 


BEGIN ... UNTIL tests:

begin
    ." hello world "
0
until

The output is the expected "hello world" text repeated over and over.

5
begin
    cr ." hello world "
    1 -
    dup
    0=
until
cr ." end of loop" cr

The output is the expected "hello world repeated
five times with the "end of loop" text at the end.

I ran these tests with just this command line:
qemu-system-ppc -nographic

It allows me to copy and paste my code into QEMU.