mingw-w64-crt/math/rint.c

/**
 * This file has no copyright assigned and is placed in the Public Domain.
 * This file is part of the mingw-w64 runtime package.
 * No warranty is given; refer to the file DISCLAIMER.PD within this package.
 */
#include <math.h>
double rint (double x) {
  double retval = 0.0;
  __asm__ __volatile__ ("frndint;" : "=t" (retval) : "0" (x));
  return retval;
}