sysdeps/i386/fpu/e_acosl.c

   1 /*
   2  * Written by J.T. Conklin <jtc@netbsd.org>.
   3  * Public domain.
   4  *
   5  * Adapted for `long double' by Ulrich Drepper <drepper@cygnus.com>.
   6  */
   7
   8 #include <math_private.h>
   9
  10 long double
  11 __ieee754_acosl (long double x)
  12 {
  13   long double res;
  14
  15   /* acosl = atanl (sqrtl(1 - x^2) / x) */
  16   asm ( "fld    %%st\n"
  17         "fmul   %%st(0)\n"              /* x^2 */
  18         "fld1\n"
  19         "fsubp\n"                       /* 1 - x^2 */
  20         "fsqrt\n"                       /* sqrtl (1 - x^2) */
  21         "fxch   %%st(1)\n"
  22         "fpatan"
  23         : "=t" (res) : "0" (x) : "st(1)");
  24   return res;
  25 }