Libfixmath
libfixmath is a platform-independent fixed-point math library aimed at developers wanting to perform fast non-integer math on platforms lacking a FPU. It offers developers a similar interface to the standard math.h functions for use on Q16.16 fixed-point numbers. libfixmath has no external dependencies other than stdint.h and a compiler which supports 64-bit integer arithmetic.
Conditional compilation options exist to remove the requirement for a 64-bit capable compiler as many compilers for microcontrollers and DSPs do not support 64-bit arithmetic.
History
libfixmath was developed by Ben Brewer and first released publicly as part of the Dingoo SDK. It has since been used to implement a software 3D graphics library called FGL.Performance
For the most intensive function benchmark results show the following results:| Name | Time Compared to Float |
| ARM Cortex-M0 | 26.3% |
| Marvell PXA270 @ 312 MHz | 58.45% |
| Intel T5500 | 120% |
| Intel Atom N280 | 141% |
Note: These results were calculated using fixtest with caching optimizations turned off.