ColdFire/68K Microcontrollers and ProcessorsのトピックRe: Need help with square root function (sqrt) on MCF52211

Need help with square root function (sqrt) on MCF52211

jayteemo — Thu, 08 May 2008 23:24:55 GMT

I'm having problems getting the sqrt (or sqrtf) function to work properly.
My targer processor is MCF52211. CodeWarrior version 5.7.0.

When I run using sqrt, the result is always 20.0 and and the exception handler is entered, resulting in the error: "Access Error: Error on operand write".

When I run using sqrtf, the result is a very large, incorrect number.

I've tried using different msl libraries.
Is there a specific library I should be using or a setting somewhere that I am missing?

Thanks.

Re: Need help with square root function (sqrt) on MCF52211

admin — Sun, 11 May 2008 19:17:54 GMT

It would probably be easier to include the source code of the sqrt() function into your program and compile it along with other sources. I suggest you use Cephes Math Library:
http://www.netlib.org/cephes/
Each function in this library is contained in a single source file. You can simply drop it into your sources folder and compile it with your project. Some minor modifications might be necessary.