mirror of
https://github.com/autc04/Retro68.git
synced 2024-12-01 11:52:47 +00:00
102 lines
2.2 KiB
C
102 lines
2.2 KiB
C
|
|
/* @(#)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) */
|