OpenCores
URL https://opencores.org/ocsvn/openrisc_me/openrisc_me/trunk

Subversion Repositories openrisc_me

[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [newlib/] [libc/] [machine/] [i386/] [f_powf.c] - Blame information for rev 207

Details | Compare with Previous | View Log

Line No. Rev Author Line
1 207 jeremybenn
/*
2
 * ====================================================
3
 * Copyright (C) 1998, 2002 by Red Hat Inc. All rights reserved.
4
 *
5
 * Permission to use, copy, modify, and distribute this
6
 * software is freely granted, provided that this notice
7
 * is preserved.
8
 * ====================================================
9
 */
10
 
11
#if !defined(_SOFT_FLOAT)
12
 
13
/*
14
Fast version of pow using Intel float instructions.
15
 
16
   float _f_powf (float x, float y);
17
 
18
Function calculates x to power of y.
19
The function optimizes the case where x is >0.0 and y is finite.
20
In such a case, there is no error checking or setting of errno.
21
All other cases defer to normal powf() function which will
22
set errno as normal.
23
*/
24
 
25
#include <math.h>
26
#include <ieeefp.h>
27
#include "f_math.h"
28
 
29
float _f_powf (float x, float y)
30
{
31
  /* following sequence handles the majority of cases for pow() */
32
  if (x > 0.0 && check_finitef(y))
33
    {
34
      float result;
35
      /* calculate x ** y as 2 ** (y log2(x)).  On Intel, can only
36
         raise 2 to an integer or a small fraction, thus, we have
37
         to perform two steps 2**integer portion * 2**fraction. */
38
      asm ("flds 8(%%ebp); fyl2x; fld %%st; frndint; fsub %%st,%%st(1);" \
39
           "fxch; fchs; f2xm1; fld1; faddp; fxch; fld1; fscale; fstp %%st(1);"\
40
           "fmulp" : "=t" (result) : "0" (y));
41
      return result;
42
    }
43
  else /* all other strange cases, defer to normal pow() */
44
    return powf (x,y);
45
}
46
 
47
#endif

powered by: WebSVN 2.1.0

© copyright 1999-2024 OpenCores.org, equivalent to Oliscience, all rights reserved. OpenCores®, registered trademark.