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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/ceil.c | |
Initial version
Diffstat (limited to 'src/math/ceil.c')
| -rw-r--r-- | src/math/ceil.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/src/math/ceil.c b/src/math/ceil.c new file mode 100644 index 0000000..b13e6f2 --- /dev/null +++ b/src/math/ceil.c @@ -0,0 +1,31 @@ +#include "libm.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 ceil(double x) +{ + union {double f; uint64_t i;} u = {x}; + int e = u.i >> 52 & 0x7ff; + double_t y; + + if (e >= 0x3ff+52 || x == 0) + return x; + /* y = int(x) - x, where int(x) is an integer neighbor of x */ + if (u.i >> 63) + y = x - toint + toint - x; + else + y = x + toint - toint - x; + /* special case because of non-nearest rounding modes */ + if (e <= 0x3ff-1) { + FORCE_EVAL(y); + return u.i >> 63 ? -0.0 : 1; + } + if (y < 0) + return x + y + 1; + return x + y; +} |