start documenting functions in the MathSpecial namespace

src/math_special.cpp

@@ -706,6 +706,7 @@ static const double fm_exp2_p[] = {
 
 double MathSpecial::exp2_x86(double x)
 {
+#if defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
     double   ipart, fpart, px, qx;
     udi_t    epart;
 
@@ -726,6 +727,9 @@ double MathSpecial::exp2_x86(double x)
 
     x = 1.0 + 2.0*(px/(qx-px));
     return epart.f*x;
+#else
+    return pow(2.0, x);
+#endif
 }
 
 double MathSpecial::fm_exp(double x)