25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/*
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * CDDL HEADER START
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis *
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * The contents of this file are subject to the terms of the
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Common Development and Distribution License (the "License").
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * You may not use this file except in compliance with the License.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis *
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * or http://www.opensolaris.org/os/licensing.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * See the License for the specific language governing permissions
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * and limitations under the License.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis *
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * When distributing Covered Code, include this CDDL HEADER in each
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * If applicable, add the following below this CDDL HEADER, with the
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * fields enclosed by brackets "[]" replaced with your own identifying
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * information: Portions Copyright [yyyy] [name of copyright owner]
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis *
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * CDDL HEADER END
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/*
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/*
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Use is subject to license terms.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
ddc0e0b53c661f6e439e3b7072b3ef353eadb4afRichard Lowe#pragma weak __scalbn = scalbn
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#include "libm.h"
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtisstatic const double
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis one = 1.0,
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis huge = 1.0e300,
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis tiny = 1.0e-300,
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis twom54 = 5.5511151231257827021181583404541015625e-17;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
1ec68d336ba97cd53f46053ac10401d16014d075Richard Lowe#if defined(__x86)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtisstatic const double two52 = 4503599627370496.0;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#else
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/*
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Normalize non-zero subnormal x and return biased exponent of x in [-51,0]
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtisstatic int
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtisilogb_biased(unsigned *px) {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis int s = 52;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis unsigned v = px[HIWORD] & ~0x80000000, w = px[LOWORD], t = v;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis if (t)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis s -= 32;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis else
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis t = w;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis if (t & 0xffff0000)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis s -= 16, t >>= 16;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis if (t & 0xff00)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis s -= 8, t >>= 8;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis if (t & 0xf0)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis s -= 4, t >>= 4;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis t <<= 1;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis s -= (0xffffaa50 >> t) & 0x3;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis if (s < 32) {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis v = (v << s) | w >> (32 - s);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis w <<= s;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis } else {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis v = w << (s - 32);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis w = 0;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis }
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis px[HIWORD] = (px[HIWORD] & 0x80000000) | v;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis px[LOWORD] = w;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis return (1 - s);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis}
1ec68d336ba97cd53f46053ac10401d16014d075Richard Lowe#endif /* defined(__x86) */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtisdouble
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtisscalbn(double x, int n) {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis int *px, ix, hx, k;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis px = (int *)&x;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis ix = px[HIWORD];
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis hx = ix & ~0x80000000;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis k = hx >> 20;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis if (k == 0x7ff) /* x is inf or NaN */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis return (x * one);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis if (k == 0) {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis if ((hx | px[LOWORD]) == 0 || n == 0)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis return (x);
1ec68d336ba97cd53f46053ac10401d16014d075Richard Lowe#if defined(__x86)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis x *= two52;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis ix = px[HIWORD];
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis k = ((ix & ~0x80000000) >> 20) - 52;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#else
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis k = ilogb_biased((unsigned *)px);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis ix = px[HIWORD];
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#endif
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis /* now k is in the range -51..0 */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis k += n;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis if (k > n) /* integer overflow occurred */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis k = -100;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis } else {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis /* k is in the range 1..1023 */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis k += n;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis if (k < n) /* integer overflow occurred */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis k = 0x7ff;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis }
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis if (k > 0x7fe)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis return (huge * ((ix < 0)? -huge : huge));
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis if (k < 1) {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis if (k <= -54)
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis return (tiny * ((ix < 0)? -tiny : tiny));
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis k += 54;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis px[HIWORD] = (ix & ~0x7ff00000) | (k << 20);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis return (x * twom54);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis }
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis px[HIWORD] = (ix & ~0x7ff00000) | (k << 20);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis return (x);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis}