mingw-w64-crt/math/atan2f.c

/*
 * Written by J.T. Conklin <jtc@netbsd.org>.
 * Public domain.
 *
 */

#include <math.h>

float
atan2f (float y, float x)
{
  float res;
  asm ("fpatan" : "=t" (res) : "u" (y), "0" (x) : "st(1)");
  return res;
}