[OpenBIOS] b?branch

[Jd Lyons]

> On Dec 21, 2017, at 9:59 AM, Programmingkid <programmingkidx at gmail.com> wrote:
> 
> 
>> On Dec 21, 2017, at 9:36 AM, Jd Lyons <lyons_dj at yahoo.com> wrote:
>> 
>> 
>> I don’t know, this maybe an issue with the way we have defined “us”.
>> 
>> Looking through the SLOF code it seems they call it like this in the timebase.fs:
>> 
>> : tb@  ( -- tb )
>>   BEGIN tbu@ tbl@ tbu@ rot over <> WHILE 2drop REPEAT
>>   20 lshift swap ffffffff and or
>> ;
>> 
>> : milliseconds ( -- ms ) tb@ d# 1000 * tb-frequency / ;
>> : microseconds ( -- us ) tb@ d# 1000000 * tb-frequency / ;
>> 
>> : ms ( ms-to-wait -- ) milliseconds + BEGIN milliseconds over >= UNTIL drop ;
>> : get-msecs ( -- n ) milliseconds ;
>> : us  ( us-to-wait -- )  microseconds +  BEGIN microseconds over >= UNTIL  drop ;
>> 
>> Not sure if I can port/hack this code over, the copier seems to have trouble with tbu@ tbl@?
>> 
> 
> The ms and get-msecs words don't appear to be implemented correctly on OpenBIOS. 10000 ms should pause OpenBIOS for 10 seconds. It does not. 
> 
> I did find a function called udelay() in the drivers/timer.c file. Maybe I can implement the word us using udelay(). Then the ms word could be implemented using the us word.


See what you can do about : us, but we maybe running into an issue with Qemu/mac99. Every version of the Mac OS reports a different bus and cpu speed, so we maybe having trouble with the way the timebase is calculated in Qemu. 

I imagine it is difficult to emulate a  fixed frequency isolator, or I’m way off base and people should just ignore me;-)

Just spitballing, really.