Disable softfloat FPU exceptions
lazarus / 43-Android

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meanderix · 2012-06-25 16:44

I was getting FPU underflow exceptions when using the software
emulated floats (I did not get this with an ordinary FPU.)

However, I figured out that everything worked fine if I added the
following line when starting my app:
Code: [Select]  softfloat_exception_mask := $ff;        // from Math
unit
Reposting here in case anyone else should come across this problem.

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meanderix · 2012-07-26 10:48

Ok, I found the source of my floating point errors:
Code: [Select]  function power(base,exponent : float) : float;
  begin
    if Exponent=0.0 then
      result:=1.0
    else if (base=0.0) and (exponent>0.0) then
      result:=0.0
    else if (abs(exponent)<=maxint) and (frac(exponent)=0.0) then
      result:=intpower(base,trunc(exponent))
    else if base>0.0 then
      result:=exp(exponent * ln (base))
    else
      InvalidArgument;
  end;
This function is not working correctly, but it works fine if I change
it like this:
Code: [Select]  function power(base,exponent : float) : float;
  begin
    if Exponent=0.0 then
      result:=1.0
    else if (base=0.0) and (exponent>0.0) then
      result:=0.0
    else if base>0.0 then
      result:=exp(exponent * ln (base))
    else
      InvalidArgument;
  end;
Should this be reported?