Altivec 'bug' or limitation?
Altivec 'bug' or limitation?
- Subject: Altivec 'bug' or limitation?
- From: Scott Horn <email@hidden>
- Date: Sat, 29 Jan 2005 14:16:24 -0800
This is a curiosity question. I've no experience in distributed or high-precision software development. I just noticed a funny thing when playing around with xgrid at home.
In Xgrid Preview 2, with two CPUs, a 800mhz G3 and a 1.25ghz G4. Running mandelbrot, manual zoom, the following coords:
X: -0.7499982136839042
Y: -0.008411978256855454
Width: 4.903769581863252e-07
With 'Use Altivec if available' is checked I get 7 squares with horizontal colored lines, and two squares with the (apparently) correct rendering. I surmise that the two correct squares were calculated by the G3 and the seven incorrect ones by the G4.
To test this I turn off Altivec and run 'Show Image' again. This time all nine squares return apparently correct results.
Question: Is this possibly a bug in the altivec libraries or hardware, or in the mandelbrot app, or is it simply a mathematical precision limitation of altivec?
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Xcode-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden