winsup/cygwin/math/asinl.c

   1 /**
   2  * This file has no copyright assigned and is placed in the Public Domain.
   3  * This file is part of the mingw-w64 runtime package.
   4  * No warranty is given; refer to the file DISCLAIMER.PD within this package.
   5  */
   6 /*
   7  * Written by J.T. Conklin <jtc@netbsd.org>.
   8  * Public domain.
   9  * Adapted for long double type by Danny Smith <dannysmith@users.sourceforge.net>.
  10  */
  11
  12 /* asin = atan (x / sqrt(1 - x^2)) */
  13 long double asinl (long double x);
  14
  15 long double asinl (long double x)
  16 {
  17   long double res = 0.0L;
  18
  19   asm volatile (
  20         "fld    %%st\n\t"
  21         "fmul   %%st(0)\n\t"                    /* x^2 */
  22         "fld1\n\t"
  23         "fsubp\n\t"                             /* 1 - x^2 */
  24         "fsqrt\n\t"                             /* sqrt (1 - x^2) */
  25         "fpatan"
  26         : "=t" (res) : "0" (x) : "st(1)");
  27   return res;
  28 }