diff options
| author | Ian Moffett <ian@osmora.org> | 2025-07-14 22:39:34 -0400 |
|---|---|---|
| committer | Ian Moffett <ian@osmora.org> | 2025-07-14 23:27:58 -0400 |
| commit | 30634165980deaeead9f4e71e0ff6a5c9d897776 (patch) | |
| tree | 18546a9d493a699eb3ea23ab5cc792d40cf82d7d /lib/libc/src/musl-math/round.c | |
| parent | 83acdbef7ae961c2ae296835df3f368573c89eeb (diff) | |
usr: libc: Add math.h + musl math impl portexpt
Signed-off-by: Ian Moffett <ian@osmora.org>
Diffstat (limited to 'lib/libc/src/musl-math/round.c')
| -rw-r--r-- | lib/libc/src/musl-math/round.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/lib/libc/src/musl-math/round.c b/lib/libc/src/musl-math/round.c new file mode 100644 index 0000000..130d58d --- /dev/null +++ b/lib/libc/src/musl-math/round.c @@ -0,0 +1,35 @@ +#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 round(double x) +{ + union {double f; uint64_t i;} u = {x}; + int e = u.i >> 52 & 0x7ff; + double_t y; + + if (e >= 0x3ff+52) + return x; + if (u.i >> 63) + x = -x; + if (e < 0x3ff-1) { + /* raise inexact if x!=0 */ + FORCE_EVAL(x + toint); + return 0*u.f; + } + y = x + toint - toint - x; + if (y > 0.5) + y = y + x - 1; + else if (y <= -0.5) + y = y + x + 1; + else + y = y + x; + if (u.i >> 63) + y = -y; + return y; +} |