[info-mcl] RMCL 5.2 on Snow Leopard: floating point issues

[Alexander Repenning]

Are you saying you are getting floating point problems after calling  
(choose-directory-dialog) with 10.5 or are you just saying you also  
get spinning beach ball kind of behaviors with 10.5?

I can certainly remember some cases in which (choose-directory-dialog)  
and similar functions would result in some sluggish and sometimes, but  
rarely, crashing type of situation but the floating point issue  
appears to be completely 10.6 specific and could likely be the result  
of the new implementation of Rosetta.

(choose-directory-dialog) and friends call navigation services  
functions including some somewhat tricky call back stuff. Getting  
memory corruption does not appear to be a likely cause for this  
systematic problem. After calling (choose-directory-dialog) RMCLs  
float functionality is completely and systematically broken. No  
function and expression of any kind or form can return any float value  
other than 0.0

Welcome to Macintosh Common Lisp Version 5.2!
? (choose-directory-dialog)
#P"Double Ristretto:ASI-Products:AgentCubes:AgentCubes RMCL  
5.2:binaries:"
? 3.3
0.0
? 1
1
? (+ 4 5)
9
? (+ 4 5.5)
0.0
? (read-from-string "3.3")
0.0
? (sin 3.0)
0.0

Things are not any better with doubles:

? (float 3 0.0d0)
1.060997897D-314


I tracked down the location of the problem a bit deeper. The float  
operations are still OK immediately before calling _NavDialogRun but  
are broken right after it. This is not terribly surprising. Still not  
clear if there is something wrong with the dialog setup or with the  
actual call to_NavDialogRun. There are many carbon app still using  
these navigation services. The answer must be more complex than that.


Navigation services in pre Snow Leopard may have caused some problems  
but AFAIK nothing that had anything to do with floats. What can cause  
this kind of behavior? How is it connected to Rosetta 10.6? Can it be  
fixed or do we need some work around such as perhaps calling the file  
chooser via Cocoa functions?

very puzzling,  Alex





On Oct 16, 2009, at 6:07 AM, Toomas Altosaar wrote:

> Exactly the same problem observed here with List
> view, MCL 5.1b4, all running on 10.5.8 on PPC!

Prof. Alexander Repenning

University of Colorado
Computer Science Department
Boulder, CO 80309-430

vCard: http://www.cs.colorado.edu/~ralex/AlexanderRepenning.vcf