diff options
| -rw-r--r-- | lib/libm_dbl/round.c | 35 | ||||
| -rw-r--r-- | ports/stm32/Makefile | 1 |
2 files changed, 36 insertions, 0 deletions
diff --git a/lib/libm_dbl/round.c b/lib/libm_dbl/round.c new file mode 100644 index 000000000..130d58d25 --- /dev/null +++ b/lib/libm_dbl/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; +} diff --git a/ports/stm32/Makefile b/ports/stm32/Makefile index fe8f0b871..e7d2e2abc 100644 --- a/ports/stm32/Makefile +++ b/ports/stm32/Makefile @@ -191,6 +191,7 @@ LIBM_SRC_C = $(addprefix lib/libm_dbl/,\ nearbyint.c \ pow.c \ rint.c \ + round.c \ scalbn.c \ sin.c \ sinh.c \ |