1  /*
       2   * Public domain.
       3   *
       4   */
       5  
       6  #include <math_private.h>
       7  #include <libm-alias-finite.h>
       8  
       9  long double
      10  __ieee754_acosl (long double x)
      11  {
      12    long double res;
      13  
      14    /* acosl = atanl (sqrtl((1-x) (1+x)) / x) */
      15    asm (	"fld	%%st\n"
      16  	"fld1\n"
      17  	"fsubp\n"
      18  	"fld1\n"
      19  	"fadd	%%st(2)\n"
      20  	"fmulp\n"			/* 1 - x^2 */
      21  	"fsqrt\n"			/* sqrtl (1 - x^2) */
      22  	"fabs\n"
      23  	"fxch	%%st(1)\n"
      24  	"fpatan"
      25  	: "=t" (res) : "0" (x) : "st(1)");
      26    return res;
      27  }
      28  libm_alias_finite (__ieee754_acosl, __acosl)