The CCES run-time libraries contain high-level support for converting between fractional and floating-point values. The include file fract2float_conv.h defines functions which perform conversions between fract16, fract32, and float types.
We recommend to refer the below cces help path for more details: CrossCore® Embedded Studio 2.9.2 > Blackfin® Development Tools Documentation > C/C++ Compiler and Library Manual for Blackfin® Processors > Compiler > C/C++ Compiler Language Extensions > Compiler Built-In Functions > Converting Between Fractional and Floating-Point Values
Unfortunately, there are no library functions/ command to handle "float" type to double“ conversion.
Also, you can refer the below cces help path to know details about the available command-line switches: CrossCore® Embedded Studio 2.9.2 > Blackfin® Development Tools Documentation > C/C++ Compiler and Library Manual for Blackfin® Processors > Compiler > Compiler Command-Line Interface > C/C++ Compiler Command-Line Switches
