mirror of
https://github.com/autc04/Retro68.git
synced 2024-11-24 07:31:32 +00:00
60 lines
1.1 KiB
C
60 lines
1.1 KiB
C
|
|
/* @(#)z_frexpf.c 1.0 98/08/13 */
|
|
/******************************************************************
|
|
* frexp
|
|
*
|
|
* Input:
|
|
* d - floating point value
|
|
* exp - exponent value
|
|
*
|
|
* Output:
|
|
* A floating point value in the range [0.5, 1).
|
|
*
|
|
* Description:
|
|
* This routine breaks a floating point value into a number f and
|
|
* an exponent exp such that d = f * 2 ^ exp.
|
|
*
|
|
*****************************************************************/
|
|
|
|
#include "fdlibm.h"
|
|
#include "zmath.h"
|
|
|
|
float frexpf (float d, int *exp)
|
|
{
|
|
float f;
|
|
__int32_t wf, wd;
|
|
|
|
/* Check for special values. */
|
|
switch (numtestf (d))
|
|
{
|
|
case NAN:
|
|
case INF:
|
|
errno = EDOM;
|
|
case 0:
|
|
*exp = 0;
|
|
return (d);
|
|
}
|
|
|
|
GET_FLOAT_WORD (wd, d);
|
|
|
|
/* Get the exponent. */
|
|
*exp = ((wd & 0x7f800000) >> 23) - 126;
|
|
|
|
/* Get the mantissa. */
|
|
wf = wd & 0x7fffff;
|
|
wf |= 0x3f000000;
|
|
|
|
SET_FLOAT_WORD (f, wf);
|
|
|
|
return (f);
|
|
}
|
|
|
|
#ifdef _DOUBLE_IS_32BITS
|
|
|
|
double frexp (double x, int *exp)
|
|
{
|
|
return (double) frexpf ((float) x, exp);
|
|
}
|
|
|
|
#endif /* defined(_DOUBLE_IS_32BITS) */
|