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| author | Vinod Polimera <quic_vpolimer@quicinc.com> | 2022-07-20 17:25:44 +0530 |
|---|---|---|
| committer | Shelley Chen <shchen@google.com> | 2022-08-03 03:26:13 +0000 |
| commit | 75283119296e5d6ce3a1c6d857a92a43ff0afec0 (patch) | |
| tree | 37fa1a7d7d853859e3c2e0a412a580912d90c33f /src/commonlib/include/commonlib/rational.h | |
| parent | 65377eba7fa0c7d46e5e88a92f667ae40ea08ef2 (diff) | |
| download | coreboot-75283119296e5d6ce3a1c6d857a92a43ff0afec0.tar.gz coreboot-75283119296e5d6ce3a1c6d857a92a43ff0afec0.tar.bz2 coreboot-75283119296e5d6ce3a1c6d857a92a43ff0afec0.zip | |
commonlib: Add support for rational number approximation
This patch adds a function to calculate best rational approximation
for a given fraction and unit tests for it.
Change-Id: I2272d9bb31cde54e65721f95662b80754eee50c2
Signed-off-by: Vinod Polimera <quic_vpolimer@quicinc.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/66010
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Diffstat (limited to 'src/commonlib/include/commonlib/rational.h')
| -rw-r--r-- | src/commonlib/include/commonlib/rational.h | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/src/commonlib/include/commonlib/rational.h b/src/commonlib/include/commonlib/rational.h new file mode 100644 index 000000000000..f172e0b191ec --- /dev/null +++ b/src/commonlib/include/commonlib/rational.h @@ -0,0 +1,22 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef _COMMONLIB_RATIONAL_H_ +#define _COMMONLIB_RATIONAL_H_ + +#include <stddef.h> + +/* + * Calculate the best rational approximation for a given fraction, + * with the restriction of maximum numerator and denominator. + * For example, to find the approximation of 3.1415 with 5 bit denominator + * and 8 bit numerator fields: + * + * rational_best_approximation(31415, 10000, + * (1 << 8) - 1, (1 << 5) - 1, &n, &d); + */ +void rational_best_approximation( + unsigned long numerator, unsigned long denominator, + unsigned long max_numerator, unsigned long max_denominator, + unsigned long *best_numerator, unsigned long *best_denominator); + +#endif /* _COMMONLIB_RATIONAL_H_ */ |