1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License (the "License"). 6 * You may not use this file except in compliance with the License. 7 * 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 9 * or http://www.opensolaris.org/os/licensing. 10 * See the License for the specific language governing permissions 11 * and limitations under the License. 12 * 13 * When distributing Covered Code, include this CDDL HEADER in each 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 15 * If applicable, add the following below this CDDL HEADER, with the 16 * fields enclosed by brackets "[]" replaced with your own identifying 17 * information: Portions Copyright [yyyy] [name of copyright owner] 18 * 19 * CDDL HEADER END 20 */ 21 22 /* 23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved. 24 */ 25 /* 26 * Copyright 2006 Sun Microsystems, Inc. All rights reserved. 27 * Use is subject to license terms. 28 */ 29 30 #if defined(ELFOBJ) 31 #pragma weak scalblnf = __scalblnf 32 #endif 33 34 #include "libm.h" 35 #include <float.h> /* FLT_MAX, FLT_MIN */ 36 37 static const float twom25f = 2.98023223876953125e-8F; 38 #if defined(USE_FPSCALE) || defined(__x86) 39 static const float two23f = 8388608.0F; 40 #else 41 /* 42 * v: a non-zero subnormal |x|; returns [-22, 0] 43 */ 44 static int 45 ilogbf_biased(unsigned v) { 46 int r = -22; 47 48 if (v & 0xffff0000) 49 r += 16, v >>= 16; 50 if (v & 0xff00) 51 r += 8, v >>= 8; 52 if (v & 0xf0) 53 r += 4, v >>= 4; 54 v <<= 1; 55 return (r + ((0xffffaa50 >> v) & 0x3)); 56 } 57 #endif /* defined(USE_FPSCALE) */ 58 59 float 60 scalblnf(float x, long n) { 61 int *px = (int *) &x, ix, k; 62 63 ix = *px & ~0x80000000; 64 k = ix >> 23; 65 if (k == 0xff) 66 #if defined(FPADD_TRAPS_INCOMPLETE_ON_NAN) 67 return (ix > 0x7f800000 ? x * x : x); 68 #else 69 return (x + x); 70 #endif 71 if (ix == 0 || n == 0) 72 return (x); 73 if (k == 0) { 74 #if defined(USE_FPSCALE) || defined(__x86) 75 x *= two23f; 76 k = ((*px & ~0x80000000) >> 23) - 23; 77 #else 78 k = ilogbf_biased(ix); 79 *px = (*px & 0x80000000) | (ix << (-k + 1)); 80 #endif 81 } 82 k += (int) n; 83 if (n > 5000 || k > 0xfe) 84 return (FLT_MAX * copysignf(FLT_MAX, x)); 85 if (n < -5000 || k <= -25) 86 return (FLT_MIN * copysignf(FLT_MIN, x)); 87 if (k > 0) { 88 *px = (*px & ~0x7f800000) | (k << 23); 89 return (x); 90 } 91 k += 25; 92 *px = (*px & ~0x7f800000) | (k << 23); 93 return (x * twom25f); 94 } 95