/[jscoverage]/trunk/js/jslong.cpp
ViewVC logotype

Contents of /trunk/js/jslong.cpp

Parent Directory Parent Directory | Revision Log Revision Log


Revision 332 - (show annotations)
Thu Oct 23 19:03:33 2008 UTC (10 years, 10 months ago) by siliconforks
File size: 7695 byte(s)
Add SpiderMonkey from Firefox 3.1b1.

The following directories and files were removed:
correct/, correct.js
liveconnect/
nanojit/
t/
v8/
vprof/
xpconnect/
all JavaScript files (Y.js, call.js, if.js, math-partial-sums.js, md5.js, perfect.js, trace-test.js, trace.js)


1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* ***** BEGIN LICENSE BLOCK *****
3 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
4 *
5 * The contents of this file are subject to the Mozilla Public License Version
6 * 1.1 (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 * http://www.mozilla.org/MPL/
9 *
10 * Software distributed under the License is distributed on an "AS IS" basis,
11 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
12 * for the specific language governing rights and limitations under the
13 * License.
14 *
15 * The Original Code is Mozilla Communicator client code, released
16 * March 31, 1998.
17 *
18 * The Initial Developer of the Original Code is
19 * Netscape Communications Corporation.
20 * Portions created by the Initial Developer are Copyright (C) 1998
21 * the Initial Developer. All Rights Reserved.
22 *
23 * Contributor(s):
24 *
25 * Alternatively, the contents of this file may be used under the terms of
26 * either of the GNU General Public License Version 2 or later (the "GPL"),
27 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
28 * in which case the provisions of the GPL or the LGPL are applicable instead
29 * of those above. If you wish to allow use of your version of this file only
30 * under the terms of either the GPL or the LGPL, and not to allow others to
31 * use your version of this file under the terms of the MPL, indicate your
32 * decision by deleting the provisions above and replace them with the notice
33 * and other provisions required by the GPL or the LGPL. If you do not delete
34 * the provisions above, a recipient may use your version of this file under
35 * the terms of any one of the MPL, the GPL or the LGPL.
36 *
37 * ***** END LICENSE BLOCK ***** */
38
39 #include "jsstddef.h"
40 #include "jstypes.h"
41 #include "jslong.h"
42
43 #ifndef JS_HAVE_LONG_LONG
44 /*
45 ** Divide 64-bit a by 32-bit b, which must be normalized so its high bit is 1.
46 */
47 static void norm_udivmod32(JSUint32 *qp, JSUint32 *rp, JSUint64 a, JSUint32 b)
48 {
49 JSUint32 d1, d0, q1, q0;
50 JSUint32 r1, r0, m;
51
52 d1 = jshi16(b);
53 d0 = jslo16(b);
54 r1 = a.hi % d1;
55 q1 = a.hi / d1;
56 m = q1 * d0;
57 r1 = (r1 << 16) | jshi16(a.lo);
58 if (r1 < m) {
59 q1--, r1 += b;
60 if (r1 >= b /* i.e., we didn't get a carry when adding to r1 */
61 && r1 < m) {
62 q1--, r1 += b;
63 }
64 }
65 r1 -= m;
66 r0 = r1 % d1;
67 q0 = r1 / d1;
68 m = q0 * d0;
69 r0 = (r0 << 16) | jslo16(a.lo);
70 if (r0 < m) {
71 q0--, r0 += b;
72 if (r0 >= b
73 && r0 < m) {
74 q0--, r0 += b;
75 }
76 }
77 *qp = (q1 << 16) | q0;
78 *rp = r0 - m;
79 }
80
81 static JSUint32 CountLeadingZeros(JSUint32 a)
82 {
83 JSUint32 t;
84 JSUint32 r = 32;
85
86 if ((t = a >> 16) != 0)
87 r -= 16, a = t;
88 if ((t = a >> 8) != 0)
89 r -= 8, a = t;
90 if ((t = a >> 4) != 0)
91 r -= 4, a = t;
92 if ((t = a >> 2) != 0)
93 r -= 2, a = t;
94 if ((t = a >> 1) != 0)
95 r -= 1, a = t;
96 if (a & 1)
97 r--;
98 return r;
99 }
100
101 JS_PUBLIC_API(void) jsll_udivmod(JSUint64 *qp, JSUint64 *rp, JSUint64 a, JSUint64 b)
102 {
103 JSUint32 n0, n1, n2;
104 JSUint32 q0, q1;
105 JSUint32 rsh, lsh;
106
107 n0 = a.lo;
108 n1 = a.hi;
109
110 if (b.hi == 0) {
111 if (b.lo > n1) {
112 /* (0 q0) = (n1 n0) / (0 D0) */
113
114 lsh = CountLeadingZeros(b.lo);
115
116 if (lsh) {
117 /*
118 * Normalize, i.e. make the most significant bit of the
119 * denominator be set.
120 */
121 b.lo = b.lo << lsh;
122 n1 = (n1 << lsh) | (n0 >> (32 - lsh));
123 n0 = n0 << lsh;
124 }
125
126 a.lo = n0, a.hi = n1;
127 norm_udivmod32(&q0, &n0, a, b.lo);
128 q1 = 0;
129
130 /* remainder is in n0 >> lsh */
131 } else {
132 /* (q1 q0) = (n1 n0) / (0 d0) */
133
134 if (b.lo == 0) /* user wants to divide by zero! */
135 b.lo = 1 / b.lo; /* so go ahead and crash */
136
137 lsh = CountLeadingZeros(b.lo);
138
139 if (lsh == 0) {
140 /*
141 * From (n1 >= b.lo)
142 * && (the most significant bit of b.lo is set),
143 * conclude that
144 * (the most significant bit of n1 is set)
145 * && (the leading quotient digit q1 = 1).
146 *
147 * This special case is necessary, not an optimization
148 * (Shifts counts of 32 are undefined).
149 */
150 n1 -= b.lo;
151 q1 = 1;
152 } else {
153 /*
154 * Normalize.
155 */
156 rsh = 32 - lsh;
157
158 b.lo = b.lo << lsh;
159 n2 = n1 >> rsh;
160 n1 = (n1 << lsh) | (n0 >> rsh);
161 n0 = n0 << lsh;
162
163 a.lo = n1, a.hi = n2;
164 norm_udivmod32(&q1, &n1, a, b.lo);
165 }
166
167 /* n1 != b.lo... */
168
169 a.lo = n0, a.hi = n1;
170 norm_udivmod32(&q0, &n0, a, b.lo);
171
172 /* remainder in n0 >> lsh */
173 }
174
175 if (rp) {
176 rp->lo = n0 >> lsh;
177 rp->hi = 0;
178 }
179 } else {
180 if (b.hi > n1) {
181 /* (0 0) = (n1 n0) / (D1 d0) */
182
183 q0 = 0;
184 q1 = 0;
185
186 /* remainder in (n1 n0) */
187 if (rp) {
188 rp->lo = n0;
189 rp->hi = n1;
190 }
191 } else {
192 /* (0 q0) = (n1 n0) / (d1 d0) */
193
194 lsh = CountLeadingZeros(b.hi);
195 if (lsh == 0) {
196 /*
197 * From (n1 >= b.hi)
198 * && (the most significant bit of b.hi is set),
199 * conclude that
200 * (the most significant bit of n1 is set)
201 * && (the quotient digit q0 = 0 or 1).
202 *
203 * This special case is necessary, not an optimization.
204 */
205
206 /*
207 * The condition on the next line takes advantage of that
208 * n1 >= b.hi (true due to control flow).
209 */
210 if (n1 > b.hi || n0 >= b.lo) {
211 q0 = 1;
212 a.lo = n0, a.hi = n1;
213 JSLL_SUB(a, a, b);
214 } else {
215 q0 = 0;
216 }
217 q1 = 0;
218
219 if (rp) {
220 rp->lo = n0;
221 rp->hi = n1;
222 }
223 } else {
224 JSInt64 m;
225
226 /*
227 * Normalize.
228 */
229 rsh = 32 - lsh;
230
231 b.hi = (b.hi << lsh) | (b.lo >> rsh);
232 b.lo = b.lo << lsh;
233 n2 = n1 >> rsh;
234 n1 = (n1 << lsh) | (n0 >> rsh);
235 n0 = n0 << lsh;
236
237 a.lo = n1, a.hi = n2;
238 norm_udivmod32(&q0, &n1, a, b.hi);
239 JSLL_MUL32(m, q0, b.lo);
240
241 if ((m.hi > n1) || ((m.hi == n1) && (m.lo > n0))) {
242 q0--;
243 JSLL_SUB(m, m, b);
244 }
245
246 q1 = 0;
247
248 /* Remainder is ((n1 n0) - (m1 m0)) >> lsh */
249 if (rp) {
250 a.lo = n0, a.hi = n1;
251 JSLL_SUB(a, a, m);
252 rp->lo = (a.hi << rsh) | (a.lo >> lsh);
253 rp->hi = a.hi >> lsh;
254 }
255 }
256 }
257 }
258
259 if (qp) {
260 qp->lo = q0;
261 qp->hi = q1;
262 }
263 }
264 #endif /* !JS_HAVE_LONG_LONG */

  ViewVC Help
Powered by ViewVC 1.1.24