Comments for Michael Justin's Weblog http://mikejustin.wordpress.com Fun with Software Development Wed, 06 May 2009 08:04:25 +0000 http://wordpress.com/ hourly 1 Comment on Why 1.99 suddenly no longer equals 1.99 by Delphi - Michael Justin had strange floating point results when his 8087 FPU Control Word got hosed « The Wiert Corner http://mikejustin.wordpress.com/2009/05/04/why-is-199-199/#comment-6 Delphi - Michael Justin had strange floating point results when his 8087 FPU Control Word got hosed « The Wiert Corner Wed, 06 May 2009 08:04:25 +0000 http://mikejustin.wordpress.com/?p=139#comment-6 [...] 1.7 of the Habari Active MQ Client components) posted a blog entry about a strange circumstance when 1.99 would not compare equally to 1.99. He tracked it down to the 8087 (more formally: Intel FPU) Control Word being hosed on his [...] [...] 1.7 of the Habari Active MQ Client components) posted a blog entry about a strange circumstance when 1.99 would not compare equally to 1.99. He tracked it down to the 8087 (more formally: Intel FPU) Control Word being hosed on his [...]

]]> Comment on Why 1.99 suddenly no longer equals 1.99 by jpluimers http://mikejustin.wordpress.com/2009/05/04/why-is-199-199/#comment-5 jpluimers Tue, 05 May 2009 22:50:50 +0000 http://mikejustin.wordpress.com/?p=139#comment-5 I did some more checks with Delphi 2007 and InterBase 2007: the failure does not occur. But: if I manually call Set8087CW with the values you mention, I can reproduce. The difference between $1372 (default) and $1272 (failure) is the internal mantissa precision. It changes from 64 bits to 53 bits, which is enough to make 1.99 not equal to 1.99. I have seen behaviour like this in the past with some networking stacks in the Turbo Pascal 7 era, with some C++ DLL's in the Delphi 1-3 era, and some printer drivers in the Delphi 5-7 era. What kind of system are you using? (Processor, OS, 32-bit/64-bit, drivers, etc)? --jeroen I did some more checks with Delphi 2007 and InterBase 2007: the failure does not occur.

But: if I manually call Set8087CW with the values you mention, I can reproduce.

The difference between $1372 (default) and $1272 (failure) is the internal mantissa precision. It changes from 64 bits to 53 bits, which is enough to make 1.99 not equal to 1.99.

I have seen behaviour like this in the past with some networking stacks in the Turbo Pascal 7 era, with some C++ DLL’s in the Delphi 1-3 era, and some printer drivers in the Delphi 5-7 era.

What kind of system are you using? (Processor, OS, 32-bit/64-bit, drivers, etc)?

–jeroen

]]> Comment on SourceForge.net hosted apps by zaien http://mikejustin.wordpress.com/2009/01/31/sourceforgenet-hosted-apps/#comment-3 zaien Tue, 03 Feb 2009 05:25:47 +0000 http://mikejustin.wordpress.com/2009/01/31/sourceforgenet-hosted-apps/#comment-3 yup, dotProject is the most leading project management application (PMA). as project management software, dotproject also have really intuitive user interface, including to do list, project list, and project report. you can also read my letter about dotProject in Indonesia by visit <a href="http://zaienopensource.wordpress.com" rel="nofollow">my open source blog</a> yup, dotProject is the most leading project management application (PMA). as project management software, dotproject also have really intuitive user interface, including to do list, project list, and project report.
you can also read my letter about dotProject in Indonesia by visit my open source blog

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