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| author | Zoltán Vörös <zvoros@gmail.com> | 2020-02-15 19:28:56 +0100 |
|---|---|---|
| committer | Damien George <damien@micropython.org> | 2020-07-21 11:07:19 +1000 |
| commit | 27767aafa21754e6cdbf52a719e7ce395f0fe672 (patch) | |
| tree | fb77ed92b88db11877ad3e4f59c654cc1c76b618 | |
| parent | a853fff838c1f995b9eeb0ebef5f117cfa3d5f0a (diff) | |
lib/libm_dbl: Add round.c source code.
This code is imported from musl, to match existing code in libm_dbl.
The file is also added to the build in stm32/Makefile. It's not needed by
the core code but, similar to c5cc64175be32cb1e4f3f1a249667bc9f5a12613,
allows round() to be used by user C modules or board extensions.
| -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 \ |