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11210 libm should be cstyle(1ONBLD) clean
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--- old/usr/src/lib/libm/common/C/log2.c
+++ new/usr/src/lib/libm/common/C/log2.c
1 1 /*
2 2 * CDDL HEADER START
3 3 *
4 4 * The contents of this file are subject to the terms of the
5 5 * Common Development and Distribution License (the "License").
6 6 * You may not use this file except in compliance with the License.
7 7 *
8 8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 9 * or http://www.opensolaris.org/os/licensing.
10 10 * See the License for the specific language governing permissions
11 11 * and limitations under the License.
12 12 *
13 13 * When distributing Covered Code, include this CDDL HEADER in each
14 14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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15 15 * If applicable, add the following below this CDDL HEADER, with the
16 16 * fields enclosed by brackets "[]" replaced with your own identifying
17 17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 18 *
19 19 * CDDL HEADER END
20 20 */
21 21
22 22 /*
23 23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
24 24 */
25 +
25 26 /*
26 27 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
27 28 * Use is subject to license terms.
28 29 */
29 30
30 31 #pragma weak __log2 = log2
31 32
32 -/* INDENT OFF */
33 +
33 34 /*
34 35 * log2(x) = log(x)/log2
35 36 *
36 37 * Base on Table look-up algorithm with product polynomial
37 38 * approximation for log(x).
38 39 *
39 40 * By K.C. Ng, Nov 29, 2004
40 41 *
41 42 * (a). For x in [1-0.125, 1+0.125], from log.c we have
42 43 * log(x) = f + ((a1*f^2) *
43 44 * ((a2 + (a3*f)*(a4+f)) + (f^3)*(a5+f))) *
44 45 * (((a6 + f*(a7+f)) + (f^3)*(a8+f)) *
45 46 * ((a9 + (a10*f)*(a11+f)) + (f^3)*(a12+f)))
46 47 * where f = x - 1.
47 48 * (i) modify a1 <- a1 / log2
48 49 * (ii) 1/log2 = 1.4426950408889634...
49 50 * = 1.5 - 0.057304959... (4 bit shift)
50 51 * Let lv = 1.5 - 1/log2, then
51 52 * lv = 0.057304959111036592640075318998107956665325,
52 53 * (iii) f*1.5 is exact because f has 3 trailing zero.
53 54 * (iv) Thus, log2(x) = f*1.5 - (lv*f - PPoly)
54 55 *
55 56 * (b). For 0.09375 <= x < 24
56 57 * Let j = (ix - 0x3fb80000) >> 15. Look up Y[j], 1/Y[j], and log(Y[j])
57 58 * from _TBL_log.c. Then
58 59 * log2(x) = log2(Y[j]) + log2(1 + (x-Y[j])*(1/Y[j]))
59 60 * = log(Y[j])(1/log2) + log2(1 + s)
60 61 * where
61 62 * s = (x-Y[j])*(1/Y[j])
62 63 * From log.c, we have log(1+s) =
63 64 * 2 2 2
64 65 * (b s) (b + b s + s ) [b + b s + s (b + s)] (b + b s + s )
65 66 * 1 2 3 4 5 6 7 8
66 67 *
67 68 * By setting b1 <- b1/log2, we have
68 69 * log2(x) = 1.5 * T - (lv * T - POLY(s))
69 70 *
70 71 * (c). Otherwise, get "n", the exponent of x, and then normalize x to
71 72 * z in [1,2). Then similar to (b) find a Y[i] that matches z to 5.5
72 73 * significant bits. Then
73 74 * log2(x) = n + log2(z).
74 75 *
75 76 * Special cases:
76 77 * log2(x) is NaN with signal if x < 0 (including -INF) ;
77 78 * log2(+INF) is +INF; log2(0) is -INF with signal;
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78 79 * log2(NaN) is that NaN with no signal.
79 80 *
80 81 * Maximum error observed: less than 0.84 ulp
81 82 *
82 83 * Constants:
83 84 * The hexadecimal values are the intended ones for the following constants.
84 85 * The decimal values may be used, provided that the compiler will convert
85 86 * from decimal to binary accurately enough to produce the hexadecimal values
86 87 * shown.
87 88 */
88 -/* INDENT ON */
89 89
90 90 #include "libm.h"
91 91 #include "libm_protos.h"
92 92
93 93 extern const double _TBL_log[];
94 94
95 95 static const double P[] = {
96 -/* ONE */ 1.0,
97 -/* TWO52 */ 4503599627370496.0,
98 -/* LN10V */ 1.4426950408889634073599246810018920433347, /* 1/log10 */
99 -/* ZERO */ 0.0,
96 +/* ONE */
97 + 1.0,
98 +/* TWO52 */ 4503599627370496.0,
99 +/* LN10V */ 1.4426950408889634073599246810018920433347, /* 1/log10 */
100 +/* ZERO */ 0.0,
100 101 /* A1 */ -9.6809362455249638217841932228967194640116e-02,
101 -/* A2 */ 1.99628461483039965074226529395673424005508422852e+0000,
102 -/* A3 */ 2.26812367662950720159642514772713184356689453125e+0000,
102 +/* A2 */ 1.99628461483039965074226529395673424005508422852e+0000,
103 +/* A3 */ 2.26812367662950720159642514772713184356689453125e+0000,
103 104 /* A4 */ -9.05030639084976384900471657601883634924888610840e-0001,
104 105 /* A5 */ -1.48275767132434044270894446526654064655303955078e+0000,
105 -/* A6 */ 1.88158320939722756293122074566781520843505859375e+0000,
106 -/* A7 */ 1.83309386046986411145098827546462416648864746094e+0000,
107 -/* A8 */ 1.24847063988317086291601754055591300129890441895e+0000,
108 -/* A9 */ 1.98372421445537705508854742220137268304824829102e+0000,
106 +/* A6 */ 1.88158320939722756293122074566781520843505859375e+0000,
107 +/* A7 */ 1.83309386046986411145098827546462416648864746094e+0000,
108 +/* A8 */ 1.24847063988317086291601754055591300129890441895e+0000,
109 +/* A9 */ 1.98372421445537705508854742220137268304824829102e+0000,
109 110 /* A10 */ -3.94711735767898475035764249696512706577777862549e-0001,
110 -/* A11 */ 3.07890395362954372160402272129431366920471191406e+0000,
111 +/* A11 */ 3.07890395362954372160402272129431366920471191406e+0000,
111 112 /* A12 */ -9.60099585275022149311041630426188930869102478027e-0001,
112 113 /* B1 */ -1.8039695622547469514898963204616532885451e-01,
113 -/* B2 */ 1.87161713283355151891381127914642725337613123482e+0000,
114 +/* B2 */ 1.87161713283355151891381127914642725337613123482e+0000,
114 115 /* B3 */ -1.89082956295731507978530316904652863740921020508e+0000,
115 116 /* B4 */ -2.50562891673640253387134180229622870683670043945e+0000,
116 -/* B5 */ 1.64822828085258366037635369139024987816810607910e+0000,
117 +/* B5 */ 1.64822828085258366037635369139024987816810607910e+0000,
117 118 /* B6 */ -1.24409107065868340669112512841820716857910156250e+0000,
118 -/* B7 */ 1.70534231658220414296067701798165217041969299316e+0000,
119 -/* B8 */ 1.99196833784655646937267192697618156671524047852e+0000,
120 -/* LGH */ 1.5,
121 -/* LGL */ 0.057304959111036592640075318998107956665325,
119 +/* B7 */ 1.70534231658220414296067701798165217041969299316e+0000,
120 +/* B8 */ 1.99196833784655646937267192697618156671524047852e+0000,
121 +/* LGH */ 1.5,
122 +/* LGL */ 0.057304959111036592640075318998107956665325,
122 123 };
123 124
124 -#define ONE P[0]
125 -#define TWO52 P[1]
126 -#define LN10V P[2]
127 -#define ZERO P[3]
128 -#define A1 P[4]
129 -#define A2 P[5]
130 -#define A3 P[6]
131 -#define A4 P[7]
132 -#define A5 P[8]
133 -#define A6 P[9]
134 -#define A7 P[10]
135 -#define A8 P[11]
136 -#define A9 P[12]
137 -#define A10 P[13]
138 -#define A11 P[14]
139 -#define A12 P[15]
140 -#define B1 P[16]
141 -#define B2 P[17]
142 -#define B3 P[18]
143 -#define B4 P[19]
144 -#define B5 P[20]
145 -#define B6 P[21]
146 -#define B7 P[22]
147 -#define B8 P[23]
148 -#define LGH P[24]
149 -#define LGL P[25]
125 +#define ONE P[0]
126 +#define TWO52 P[1]
127 +#define LN10V P[2]
128 +#define ZERO P[3]
129 +#define A1 P[4]
130 +#define A2 P[5]
131 +#define A3 P[6]
132 +#define A4 P[7]
133 +#define A5 P[8]
134 +#define A6 P[9]
135 +#define A7 P[10]
136 +#define A8 P[11]
137 +#define A9 P[12]
138 +#define A10 P[13]
139 +#define A11 P[14]
140 +#define A12 P[15]
141 +#define B1 P[16]
142 +#define B2 P[17]
143 +#define B3 P[18]
144 +#define B4 P[19]
145 +#define B5 P[20]
146 +#define B6 P[21]
147 +#define B7 P[22]
148 +#define B8 P[23]
149 +#define LGH P[24]
150 +#define LGL P[25]
150 151
151 152 double
152 -log2(double x) {
153 +log2(double x)
154 +{
153 155 int i, hx, ix, n, lx;
154 156
155 157 n = 0;
156 - hx = ((int *) &x)[HIWORD]; ix = hx & 0x7fffffff;
157 - lx = ((int *) &x)[LOWORD];
158 + hx = ((int *)&x)[HIWORD];
159 + ix = hx & 0x7fffffff;
160 + lx = ((int *)&x)[LOWORD];
158 161
159 162 /* subnormal,0,negative,inf,nan */
160 163 if ((hx + 0x100000) < 0x200000) {
161 164 #if defined(FPADD_TRAPS_INCOMPLETE_ON_NAN)
162 - if (ix >= 0x7ff80000) /* assumes sparc-like QNaN */
163 - return (x); /* for Cheetah when x is QNaN */
165 + if (ix >= 0x7ff80000) /* assumes sparc-like QNaN */
166 + return (x); /* for Cheetah when x is QNaN */
164 167 #endif
165 - if (((hx << 1) | lx) == 0) /* log(0.0) = -inf */
168 +
169 + if (((hx << 1) | lx) == 0) /* log(0.0) = -inf */
166 170 return (A5 / fabs(x));
167 - if (hx < 0) { /* x < 0 */
171 +
172 + if (hx < 0) { /* x < 0 */
168 173 if (ix >= 0x7ff00000)
169 - return (x - x); /* x is -inf or NaN */
174 + return (x - x); /* x is -inf or NaN */
170 175 else
171 176 return (ZERO / (x - x));
172 177 }
178 +
173 179 if (((hx - 0x7ff00000) | lx) == 0) /* log(inf) = inf */
174 180 return (x);
175 - if (ix >= 0x7ff00000) /* log(NaN) = NaN */
181 +
182 + if (ix >= 0x7ff00000) /* log(NaN) = NaN */
176 183 return (x - x);
184 +
177 185 x *= TWO52;
178 186 n = -52;
179 - hx = ((int *) &x)[HIWORD]; ix = hx & 0x7fffffff;
180 - lx = ((int *) &x)[LOWORD];
187 + hx = ((int *)&x)[HIWORD];
188 + ix = hx & 0x7fffffff;
189 + lx = ((int *)&x)[LOWORD];
181 190 }
182 191
183 192 /* 0.09375 (0x3fb80000) <= x < 24 (0x40380000) */
184 193 i = ix >> 19;
194 +
185 195 if (i >= 0x7f7 && i <= 0x806) {
186 196 /* 0.875 <= x < 1.125 */
187 197 if (ix >= 0x3fec0000 && ix < 0x3ff20000) {
188 198 double s, z, r, w;
189 - s = x - ONE; z = s * s; r = (A10 * s) * (A11 + s);
199 +
200 + s = x - ONE;
201 + z = s * s;
202 + r = (A10 * s) * (A11 + s);
190 203 w = z * s;
191 - if (((ix << 12) | lx) == 0)
204 +
205 + if (((ix << 12) | lx) == 0) {
192 206 return (z);
193 - else
194 - return (LGH * s - (LGL * s - ((A1 * z) *
195 - ((A2 + (A3 * s) * (A4 + s)) + w * (A5 + s))) *
196 - (((A6 + s * (A7 + s)) + w * (A8 + s)) *
197 - ((A9 + r) + w * (A12 + s)))));
207 + } else {
208 + return (LGH * s - (LGL * s - ((A1 * z) * ((A2 +
209 + (A3 * s) * (A4 + s)) + w * (A5 + s))) *
210 + (((A6 + s * (A7 + s)) + w * (A8 + s)) *
211 + ((A9 + r) + w * (A12 + s)))));
212 + }
198 213 } else {
199 214 double *tb, s;
215 +
200 216 i = (ix - 0x3fb80000) >> 15;
201 - tb = (double *) _TBL_log + (i + i + i);
217 + tb = (double *)_TBL_log + (i + i + i);
218 +
202 219 if (((ix << 12) | lx) == 0) /* 2's power */
203 - return ((double) ((ix >> 20) - 0x3ff));
220 + return ((double)((ix >> 20) - 0x3ff));
221 +
204 222 s = (x - tb[0]) * tb[1];
205 223 return (LGH * tb[2] - (LGL * tb[2] - ((B1 * s) *
206 - (B2 + s * (B3 + s))) *
207 - (((B4 + s * B5) + (s * s) * (B6 + s)) *
208 - (B7 + s * (B8 + s)))));
224 + (B2 + s * (B3 + s))) * (((B4 + s * B5) + (s * s) *
225 + (B6 + s)) * (B7 + s * (B8 + s)))));
209 226 }
210 227 } else {
211 228 double *tb, dn, s;
212 - dn = (double) (n + ((ix >> 20) - 0x3ff));
229 +
230 + dn = (double)(n + ((ix >> 20) - 0x3ff));
213 231 ix <<= 12;
232 +
214 233 if ((ix | lx) == 0)
215 234 return (dn);
216 - i = ((unsigned) ix >> 12) | 0x3ff00000; /* scale x to [1,2) */
217 - ((int *) &x)[HIWORD] = i;
235 +
236 + i = ((unsigned)ix >> 12) | 0x3ff00000; /* scale x to [1,2) */
237 + ((int *)&x)[HIWORD] = i;
218 238 i = (i - 0x3fb80000) >> 15;
219 - tb = (double *) _TBL_log + (i + i + i);
239 + tb = (double *)_TBL_log + (i + i + i);
220 240 s = (x - tb[0]) * tb[1];
221 - return (dn + (tb[2] * LN10V + ((B1 * s) *
222 - (B2 + s * (B3 + s))) *
223 - (((B4 + s * B5) + (s * s) * (B6 + s)) *
224 - (B7 + s * (B8 + s)))));
241 + return (dn + (tb[2] * LN10V + ((B1 * s) * (B2 + s * (B3 + s))) *
242 + (((B4 + s * B5) + (s * s) * (B6 + s)) *
243 + (B7 + s * (B8 + s)))));
225 244 }
226 245 }
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