mirror of https://git.musl-libc.org/git/musl
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
83 lines
1.7 KiB
83 lines
1.7 KiB
/* origin: FreeBSD /usr/src/lib/msun/src/s_ceil.c */
|
|
/*
|
|
* ====================================================
|
|
* 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.
|
|
* ====================================================
|
|
*/
|
|
/*
|
|
* ceil(x)
|
|
* Return x rounded toward -inf to integral value
|
|
* Method:
|
|
* Bit twiddling.
|
|
* Exception:
|
|
* Inexact flag raised if x not equal to ceil(x).
|
|
*/
|
|
|
|
#include "libm.h"
|
|
|
|
static const double huge = 1.0e300;
|
|
|
|
double ceil(double x)
|
|
{
|
|
int32_t i0,i1,j0;
|
|
uint32_t i,j;
|
|
|
|
EXTRACT_WORDS(i0, i1, x);
|
|
// FIXME signed shift
|
|
j0 = ((i0>>20)&0x7ff) - 0x3ff;
|
|
if (j0 < 20) {
|
|
if (j0 < 0) {
|
|
/* raise inexact if x != 0 */
|
|
if (huge+x > 0.0) {
|
|
/* return 0*sign(x) if |x|<1 */
|
|
if (i0 < 0) {
|
|
i0 = 0x80000000;
|
|
i1=0;
|
|
} else if ((i0|i1) != 0) {
|
|
i0=0x3ff00000;
|
|
i1=0;
|
|
}
|
|
}
|
|
} else {
|
|
i = (0x000fffff)>>j0;
|
|
if (((i0&i)|i1) == 0) /* x is integral */
|
|
return x;
|
|
/* raise inexact flag */
|
|
if (huge+x > 0.0) {
|
|
if (i0 > 0)
|
|
i0 += 0x00100000>>j0;
|
|
i0 &= ~i;
|
|
i1 = 0;
|
|
}
|
|
}
|
|
} else if (j0 > 51) {
|
|
if (j0 == 0x400) /* inf or NaN */
|
|
return x+x;
|
|
return x; /* x is integral */
|
|
} else {
|
|
i = (uint32_t)0xffffffff>>(j0-20);
|
|
if ((i1&i) == 0)
|
|
return x; /* x is integral */
|
|
/* raise inexact flag */
|
|
if (huge+x > 0.0) {
|
|
if (i0 > 0) {
|
|
if (j0 == 20)
|
|
i0 += 1;
|
|
else {
|
|
j = i1 + (1<<(52-j0));
|
|
if (j < i1) /* got a carry */
|
|
i0 += 1;
|
|
i1 = j;
|
|
}
|
|
}
|
|
i1 &= ~i;
|
|
}
|
|
}
|
|
INSERT_WORDS(x, i0, i1);
|
|
return x;
|
|
}
|
|
|