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/* @(#)sf_lrint.c 5.1 93/09/24 */
/*
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunPro, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 */
 
/*
 * lrintf(x)
 * Return x rounded to integral value according to the prevailing
 * rounding mode.
 * Method:
 *      Using floating addition.
 * Exception:
 *      Inexact flag raised if x not equal to lrintf(x).
 */
 
#include "fdlibm.h"
 
#ifdef __STDC__
static const float
#else
static float
#endif
/* Adding a float, x, to 2^23 will cause the result to be rounded based on
   the fractional part of x, according to the implementation's current rounding
   mode.  2^23 is the smallest float that can be represented using all 23 significant
   digits. */
TWO23[2]={
  8.3886080000e+06, /* 0x4b000000 */
 -8.3886080000e+06, /* 0xcb000000 */
};
 
#ifdef __STDC__
        long int lrintf(float x)
#else
        long int lrintf(x)
        float x;
#endif
{
  __int32_t j0,sx;
  __uint32_t i0;
  float t;
  volatile float w;
  long int result;
 
  GET_FLOAT_WORD(i0,x);
 
  /* Extract sign bit. */
  sx = (i0 >> 31);
 
  /* Extract exponent field. */
  j0 = ((i0 & 0x7f800000) >> 23) - 127;
 
  if (j0 < (int)(sizeof (long int) * 8) - 1)
    {
      if (j0 < -1)
        return 0;
      else if (j0 >= 23)
        result = (long int) ((i0 & 0x7fffff) | 0x800000) << (j0 - 23);
      else
        {
          w = TWO23[sx] + x;
          t = w - TWO23[sx];
          GET_FLOAT_WORD (i0, t);
          /* Detect the all-zeros representation of plus and
             minus zero, which fails the calculation below. */
          if ((i0 & ~(1L << 31)) == 0)
              return 0;
          j0 = ((i0 >> 23) & 0xff) - 0x7f;
          i0 &= 0x7fffff;
          i0 |= 0x800000;
          result = i0 >> (23 - j0);
        }
    }
  else
    {
      return (long int) x;
    }
  return sx ? -result : result;
}
 
#ifdef _DOUBLE_IS_32BITS
 
#ifdef __STDC__
        long int lrint(double x)
#else
        long int lrint(x)
        double x;
#endif
{
  return lrintf((float) x);
}
 
#endif /* defined(_DOUBLE_IS_32BITS) */

Line No.	Rev	Author	Line
1	207	jeremybenn
2			`/* @(#)sf_lrint.c 5.1 93/09/24 */`
3			`/*`
4			`* ====================================================`
5			`* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.`
6			`*`
7			`* Developed at SunPro, a Sun Microsystems, Inc. business.`
8			`* Permission to use, copy, modify, and distribute this`
9			`* software is freely granted, provided that this notice`
10			`* is preserved.`
11			`* ====================================================`
12			`*/`
13
14			`/*`
15			`* lrintf(x)`
16			`* Return x rounded to integral value according to the prevailing`
17			`* rounding mode.`
18			`* Method:`
19			`* Using floating addition.`
20			`* Exception:`
21			`* Inexact flag raised if x not equal to lrintf(x).`
22			`*/`
23
24			`#include "fdlibm.h"`
25
26			`#ifdef __STDC__`
27			`static const float`
28			`#else`
29			`static float`
30			`#endif`
31			`/* Adding a float, x, to 2^23 will cause the result to be rounded based on`
32			`the fractional part of x, according to the implementation's current rounding`
33			`mode. 2^23 is the smallest float that can be represented using all 23 significant`
34			`digits. */`
35			`TWO23[2]={`
36			`8.3886080000e+06, /* 0x4b000000 */`
37			`-8.3886080000e+06, /* 0xcb000000 */`
38			`};`
39
40			`#ifdef __STDC__`
41			`long int lrintf(float x)`
42			`#else`
43			`long int lrintf(x)`
44			`float x;`
45			`#endif`
46			`{`
47			`__int32_t j0,sx;`
48			`__uint32_t i0;`
49			`float t;`
50			`volatile float w;`
51			`long int result;`
52
53			`GET_FLOAT_WORD(i0,x);`
54
55			`/* Extract sign bit. */`
56			`sx = (i0 >> 31);`
57
58			`/* Extract exponent field. */`
59			`j0 = ((i0 & 0x7f800000) >> 23) - 127;`
60
61			`if (j0 < (int)(sizeof (long int) * 8) - 1)`
62			`{`
63			`if (j0 < -1)`
64			`return 0;`
65			`else if (j0 >= 23)`
66			`result = (long int) ((i0 & 0x7fffff) \| 0x800000) << (j0 - 23);`
67			`else`
68			`{`
69			`w = TWO23[sx] + x;`
70			`t = w - TWO23[sx];`
71			`GET_FLOAT_WORD (i0, t);`
72			`/* Detect the all-zeros representation of plus and`
73			`minus zero, which fails the calculation below. */`
74			`if ((i0 & ~(1L << 31)) == 0)`
75			`return 0;`
76			`j0 = ((i0 >> 23) & 0xff) - 0x7f;`
77			`i0 &= 0x7fffff;`
78			`i0 \|= 0x800000;`
79			`result = i0 >> (23 - j0);`
80			`}`
81			`}`
82			`else`
83			`{`
84			`return (long int) x;`
85			`}`
86			`return sx ? -result : result;`
87			`}`
88
89			`#ifdef _DOUBLE_IS_32BITS`
90
91			`#ifdef __STDC__`
92			`long int lrint(double x)`
93			`#else`
94			`long int lrint(x)`
95			`double x;`
96			`#endif`
97			`{`
98			`return lrintf((float) x);`
99			`}`
100
101			`#endif /* defined(_DOUBLE_IS_32BITS) */`

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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [newlib/] [libm/] [common/] [sf_lrint.c] - Blame information for rev 207