Lerking/micropython
1
0
Fork 0
mirror of https://github.com/micropython/micropython.git synced 2026-01-04 19:20:22 +01:00
Code Issues Actions 52 Packages Projects Releases Wiki Activity

lib/libm_dbl: Add round.c source code.

Browse Source 
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 c5cc64175b,
allows round() to be used by user C modules or board extensions.
This commit is contained in:
Zoltán Vörös
2020-02-15 19:28:56 +01:00
committed by Damien George
parent a853fff838
commit 27767aafa2
2 changed files with 36 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

35
lib/libm_dbl/round.c Normal file
View File

@@ -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;
}