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| author | Vladimir Azarov <avm@intermediate-node.net> | 2024-10-01 15:47:05 +0200 |
|---|---|---|
| committer | Vladimir Azarov <avm@intermediate-node.net> | 2024-10-01 15:47:05 +0200 |
| commit | 4abab5ad6c8465a7528ccdd5f49367da05f78bbd (patch) | |
| tree | ebf009bf1376a5a223a915bc27cbbd791a1316bc /src/math/rint.c | |
Initial version
Diffstat (limited to 'src/math/rint.c')
| -rw-r--r-- | src/math/rint.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/src/math/rint.c b/src/math/rint.c new file mode 100644 index 0000000..fbba390 --- /dev/null +++ b/src/math/rint.c @@ -0,0 +1,28 @@ +#include <float.h> +#include <math.h> +#include <stdint.h> + +#if FLT_EVAL_METHOD==0 || FLT_EVAL_METHOD==1 +#define EPS DBL_EPSILON +#elif FLT_EVAL_METHOD==2 +#define EPS LDBL_EPSILON +#endif +static const double_t toint = 1/EPS; + +double rint(double x) +{ + union {double f; uint64_t i;} u = {x}; + int e = u.i>>52 & 0x7ff; + int s = u.i>>63; + double_t y; + + if (e >= 0x3ff+52) + return x; + if (s) + y = x - toint + toint; + else + y = x + toint - toint; + if (y == 0) + return s ? -0.0 : 0; + return y; +} |