Subject: Re: IIvx booting problems
To: None <nigel@ind.tansu.com.au>
From: Hauke Fath <hauke@Espresso.Rhein-Neckar.DE>
List: port-mac68k
Date: 07/28/1997 20:22:58
At 3:38 Uhr +0200 28.07.1997, nigel@ind.tansu.com.au wrote:
>* I discovered that one Booter "environment variable" was different;
> TIMEDBRA = 5217 (0x1461) with Booter 1.9.4,
> TIMEDBRA = 5221 (ox1465) with Booter 1.9.5.
TIMEDBRA is the number of times that the processor runs a
loop: dbra d0,loop
per second. As an indicator of CPU speed it is mainly used for short
delays. You are talking about a 1000 ppm difference - not really a big
deal. ;)
>Looking through the code, this value is set differently by the
>two compilers. MetroWerks calls a function LMGetTimeDBRA(), while Symantec
>dereferences a Low Memory address constant.
Apple's Universal Headers wrap accesses to low memory globals into inline
functions to be more portable; lomem globals are said to go away,
eventually.
>I am searching through some of
>the MacOs developer sites now, looking for an explaination of the
>LMGetTimeDBRA() routine.
No need to. Look for <LowMem.h> in "Universal Headers".
> I am at a loss to explain why this would _only_ affect booting on
>the IIvx models, but assuming that this is the problem, we may have a new
>Booter ready this weekend for testing.
Seems to me you're somewhat on the wrong track?
hauke
--
"It's never straight up and down" (DEVO)