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author | Romain Forlot <romain.forlot@iot.bzh> | 2017-05-19 16:20:02 +0200 |
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committer | Romain Forlot <romain.forlot@iot.bzh> | 2017-05-19 16:20:02 +0200 |
commit | 2d574dc77f68ecb5150016989900860e8b74be50 (patch) | |
tree | d691a8345a58dcd080131c58d028f77df51a45ed /CAN-binder/libs/nanopb/examples/using_double_on_avr/double_conversion.h | |
parent | 48a2605965af1f05ba7f01f6e8c1758a4c9b0522 (diff) | |
parent | 278ffb890e3d8722e4c7d824baaf221a1e375fc4 (diff) |
Add 'CAN-binder/libs/nanopb/' from commit '278ffb890e3d8722e4c7d824baaf221a1e375fc4'
git-subtree-dir: CAN-binder/libs/nanopb
git-subtree-mainline: 48a2605965af1f05ba7f01f6e8c1758a4c9b0522
git-subtree-split: 278ffb890e3d8722e4c7d824baaf221a1e375fc4
Diffstat (limited to 'CAN-binder/libs/nanopb/examples/using_double_on_avr/double_conversion.h')
-rw-r--r-- | CAN-binder/libs/nanopb/examples/using_double_on_avr/double_conversion.h | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/CAN-binder/libs/nanopb/examples/using_double_on_avr/double_conversion.h b/CAN-binder/libs/nanopb/examples/using_double_on_avr/double_conversion.h new file mode 100644 index 00000000..62b6a8ae --- /dev/null +++ b/CAN-binder/libs/nanopb/examples/using_double_on_avr/double_conversion.h @@ -0,0 +1,26 @@ +/* AVR-GCC does not have real double datatype. Instead its double + * is equal to float, i.e. 32 bit value. If you need to communicate + * with other systems that use double in their .proto files, you + * need to do some conversion. + * + * These functions use bitwise operations to mangle floats into doubles + * and then store them in uint64_t datatype. + */ + +#ifndef DOUBLE_CONVERSION +#define DOUBLE_CONVERSION + +#include <stdint.h> + +/* Convert native 4-byte float into a 8-byte double. */ +extern uint64_t float_to_double(float value); + +/* Convert 8-byte double into native 4-byte float. + * Values are rounded to nearest, 0.5 away from zero. + * Overflowing values are converted to Inf or -Inf. + */ +extern float double_to_float(uint64_t value); + + +#endif + |