rintf.c revision 25c28e83beb90e7c80452a7c818c5e6f73a07dc8
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2011 Nexenta Systems, Inc. All rights reserved.
*/
/*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#if defined(ELFOBJ)
#pragma weak aintf = __aintf
#pragma weak anintf = __anintf
#pragma weak irintf = __irintf
#pragma weak nintf = __nintf
#pragma weak rintf = __rintf
#endif
/* INDENT OFF */
/*
* aintf(x) return x chopped to integral value
* anintf(x) return sign(x)*(|x|+0.5) chopped to integral value
* irintf(x) return rint(x) in integer format
* nintf(x) return anint(x) in integer format
* rintf(x) return x rounded to integral according to the rounding direction
*
* NOTE: rintf(x), aintf(x) and anintf(x) return results with the same sign as
* x's, including 0.0.
*/
#include "libm.h"
static const float xf[] = {
/* ZEROF */ 0.0f,
/* TWO_23F */ 8.3886080000e6f,
/* MTWO_23F */ -8.3886080000e6f,
/* ONEF */ 1.0f,
/* MONEF */ -1.0f,
/* HALFF */ 0.5f,
/* MHALFF */ -0.5f,
/* HUGEF */ 1.0e30f,
};
#define ZEROF xf[0]
#define TWO_23F xf[1]
#define MTWO_23F xf[2]
#define ONEF xf[3]
#define MONEF xf[4]
#define HALFF xf[5]
#define MHALFF xf[6]
#define HUGEF xf[7]
/* INDENT ON */
float
aintf(float x) {
int hx, k;
float y;
hx = *(int *) &x;
k = (hx & ~0x80000000) >> 23;
if (k < 150) {
y = (float) ((int) x);
/*
* make sure y has the same sign of x when |x|<0.5
* (i.e., y=0.0)
*/
return (((k - 127) & hx) < 0 ? -y : y);
} else
/* signal invalid if x is a SNaN */
return (x * ONEF); /* +0 -> *1 for Cheetah */
}
float
anintf(float x) {
volatile float dummy;
int hx, k, j, ix;
hx = *(int *) &x;
ix = hx & ~0x80000000;
k = ix >> 23;
if (((k - 127) ^ (k - 150)) < 0) {
j = 1 << (149 - k);
k = j + j - 1;
if ((k & hx) != 0)
dummy = HUGEF + x; /* raise inexact */
*(int *) &x = (hx + j) & ~k;
return (x);
} else if (k <= 126) {
dummy = HUGEF + x;
*(int *) &x = (0x3f800000 & ((125 - k) >> 31)) |
(0x80000000 & hx);
return (x);
} else
/* signal invalid if x is a SNaN */
return (x * ONEF); /* +0 -> *1 for Cheetah */
}
int
irintf(float x) {
float v;
int hx, k;
hx = *(int *) &x;
k = (hx & ~0x80000000) >> 23;
v = xf[((k - 150) >> 31) & (1 - (hx >> 31))];
return ((int) ((float) (x + v) - v));
}
int
nintf(float x) {
int hx, ix, k, j, m;
volatile float dummy;
hx = *(int *) &x;
k = (hx & ~0x80000000) >> 23;
if (((k - 126) ^ (k - 150)) < 0) {
ix = (hx & 0x00ffffff) | 0x800000;
m = 149 - k;
j = 1 << m;
if ((ix & (j + j - 1)) != 0)
dummy = HUGEF + x;
hx = hx >> 31;
return ((((ix + j) >> (m + 1)) ^ hx) - hx);
} else
return ((int) x);
}
float
rintf(float x) {
float w, v;
int hx, k;
hx = *(int *) &x;
k = (hx & ~0x80000000) >> 23;
#if defined(FPADD_TRAPS_INCOMPLETE_ON_NAN)
if (k >= 150)
return (x * ONEF);
v = xf[1 - (hx >> 31)];
#else
v = xf[((k - 150) >> 31) & (1 - (hx >> 31))];
#endif
w = (float) (x + v);
if (k < 127 && w == v)
return (ZEROF * x);
else
return (w - v);
}