-/* Math functions for i387.
- Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
- This file is part of the GNU C Library.
- Contributed by John C. Bowman <bowman@ipp-garching.mpg.de>, 1995.
-
- The GNU C Library is free software; you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public
- License as published by the Free Software Foundation; either
- version 2.1 of the License, or (at your option) any later version.
-
- The GNU C Library is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public
- License along with the GNU C Library; if not, write to the Free
- Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
- Boston, MA 02110-1301, USA.
-*/
-
-#include <math.h>
-
-double exp (double __x);
-
-double exp (double __x)
-{
-#ifdef __GNUC__
- register double __value, __exponent;
- __asm __volatile__
- ("fldl2e # e^x = 2^(x * log2(e))\n\t"
- "fmul %%st(1) # x * log2(e)\n\t"
- "fst %%st(1)\n\t"
- "frndint # int(x * log2(e))\n\t"
- "fxch\n\t"
- "fsub %%st(1) # fract(x * log2(e))\n\t"
- "f2xm1 # 2^(fract(x * log2(e))) - 1\n\t"
- : "=t" (__value), "=u" (__exponent) : "0" (__x));
- __value += 1.0;
- __asm __volatile__
- ("fscale"
- : "=t" (__value) : "0" (__value), "u" (__exponent));
-
- return __value;
-#else
- register double __val;
- __asm
- {
- fld1 // store 1.0 for later use
- fld __x
- fldl2e // e^x = 2^(x * log2(e))
- fmul st,st(1) // x * log2(e)
- fld st(0)
- frndint // int(x * log2(e))
- fsub st,st(1) // fract(x * log2(e))
- fxch
- f2xm1 // 2^(fract(x * log2(e))) - 1
- fadd st,st(3) // + 1.0
- fscale
- fstp __val
- }
- return __val;
-#endif /*__GNUC__*/
-}