ia64/xen-unstable

view xen/common/lib.c @ 19835:edfdeb150f27

Fix buildsystem to detect udev > version 124

udev removed the udevinfo symlink from versions higher than 123 and
xen's build-system could not detect if udev is in place and has the
required version.

Signed-off-by: Marc-A. Dahlhaus <mad@wol.de>
author Keir Fraser <keir.fraser@citrix.com>
date Thu Jun 25 13:02:37 2009 +0100 (2009-06-25)
parents 50634c215234
children
line source
2 #include <xen/ctype.h>
3 #include <xen/lib.h>
4 #include <xen/types.h>
5 #include <asm/byteorder.h>
7 /* for ctype.h */
8 unsigned char _ctype[] = {
9 _C,_C,_C,_C,_C,_C,_C,_C, /* 0-7 */
10 _C,_C|_S,_C|_S,_C|_S,_C|_S,_C|_S,_C,_C, /* 8-15 */
11 _C,_C,_C,_C,_C,_C,_C,_C, /* 16-23 */
12 _C,_C,_C,_C,_C,_C,_C,_C, /* 24-31 */
13 _S|_SP,_P,_P,_P,_P,_P,_P,_P, /* 32-39 */
14 _P,_P,_P,_P,_P,_P,_P,_P, /* 40-47 */
15 _D,_D,_D,_D,_D,_D,_D,_D, /* 48-55 */
16 _D,_D,_P,_P,_P,_P,_P,_P, /* 56-63 */
17 _P,_U|_X,_U|_X,_U|_X,_U|_X,_U|_X,_U|_X,_U, /* 64-71 */
18 _U,_U,_U,_U,_U,_U,_U,_U, /* 72-79 */
19 _U,_U,_U,_U,_U,_U,_U,_U, /* 80-87 */
20 _U,_U,_U,_P,_P,_P,_P,_P, /* 88-95 */
21 _P,_L|_X,_L|_X,_L|_X,_L|_X,_L|_X,_L|_X,_L, /* 96-103 */
22 _L,_L,_L,_L,_L,_L,_L,_L, /* 104-111 */
23 _L,_L,_L,_L,_L,_L,_L,_L, /* 112-119 */
24 _L,_L,_L,_P,_P,_P,_P,_C, /* 120-127 */
25 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* 128-143 */
26 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* 144-159 */
27 _S|_SP,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P, /* 160-175 */
28 _P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P, /* 176-191 */
29 _U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U, /* 192-207 */
30 _U,_U,_U,_U,_U,_U,_U,_P,_U,_U,_U,_U,_U,_U,_U,_L, /* 208-223 */
31 _L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L, /* 224-239 */
32 _L,_L,_L,_L,_L,_L,_L,_P,_L,_L,_L,_L,_L,_L,_L,_L}; /* 240-255 */
34 /*
35 * A couple of 64 bit operations ported from FreeBSD.
36 * The code within the '#if BITS_PER_LONG == 32' block below, and no other
37 * code in this file, is distributed under the following licensing terms
38 * This is the modified '3-clause' BSD license with the obnoxious
39 * advertising clause removed, as permitted by University of California.
40 *
41 * Copyright (c) 1992, 1993
42 * The Regents of the University of California. All rights reserved.
43 *
44 * This software was developed by the Computer Systems Engineering group
45 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
46 * contributed to Berkeley.
47 *
48 * Redistribution and use in source and binary forms, with or without
49 * modification, are permitted provided that the following conditions
50 * are met:
51 * 1. Redistributions of source code must retain the above copyright
52 * notice, this list of conditions and the following disclaimer.
53 * 2. Redistributions in binary form must reproduce the above copyright
54 * notice, this list of conditions and the following disclaimer in the
55 * documentation and/or other materials provided with the distribution.
56 * 3. Neither the name of the University nor the names of its contributors
57 * may be used to endorse or promote products derived from this software
58 * without specific prior written permission.
59 *
60 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
61 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
62 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
63 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
64 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
65 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
66 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
67 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
68 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
69 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
70 * SUCH DAMAGE.
71 */
72 #if BITS_PER_LONG == 32
74 /*
75 * Depending on the desired operation, we view a `long long' (aka quad_t) in
76 * one or more of the following formats.
77 */
78 union uu {
79 s64 q; /* as a (signed) quad */
80 s64 uq; /* as an unsigned quad */
81 long sl[2]; /* as two signed longs */
82 unsigned long ul[2]; /* as two unsigned longs */
83 };
85 #ifdef __BIG_ENDIAN
86 #define _QUAD_HIGHWORD 0
87 #define _QUAD_LOWWORD 1
88 #else /* __LITTLE_ENDIAN */
89 #define _QUAD_HIGHWORD 1
90 #define _QUAD_LOWWORD 0
91 #endif
93 /*
94 * Define high and low longwords.
95 */
96 #define H _QUAD_HIGHWORD
97 #define L _QUAD_LOWWORD
99 /*
100 * Total number of bits in a quad_t and in the pieces that make it up.
101 * These are used for shifting, and also below for halfword extraction
102 * and assembly.
103 */
104 #define CHAR_BIT 8 /* number of bits in a char */
105 #define QUAD_BITS (sizeof(s64) * CHAR_BIT)
106 #define LONG_BITS (sizeof(long) * CHAR_BIT)
107 #define HALF_BITS (sizeof(long) * CHAR_BIT / 2)
109 /*
110 * Extract high and low shortwords from longword, and move low shortword of
111 * longword to upper half of long, i.e., produce the upper longword of
112 * ((quad_t)(x) << (number_of_bits_in_long/2)). (`x' must actually be u_long.)
113 *
114 * These are used in the multiply code, to split a longword into upper
115 * and lower halves, and to reassemble a product as a quad_t, shifted left
116 * (sizeof(long)*CHAR_BIT/2).
117 */
118 #define HHALF(x) ((x) >> HALF_BITS)
119 #define LHALF(x) ((x) & ((1 << HALF_BITS) - 1))
120 #define LHUP(x) ((x) << HALF_BITS)
122 /*
123 * Multiprecision divide. This algorithm is from Knuth vol. 2 (2nd ed),
124 * section 4.3.1, pp. 257--259.
125 */
126 #define B (1 << HALF_BITS) /* digit base */
128 /* Combine two `digits' to make a single two-digit number. */
129 #define COMBINE(a, b) (((u_long)(a) << HALF_BITS) | (b))
131 /* select a type for digits in base B */
132 typedef u_long digit;
134 /*
135 * Shift p[0]..p[len] left `sh' bits, ignoring any bits that
136 * `fall out' the left (there never will be any such anyway).
137 * We may assume len >= 0. NOTE THAT THIS WRITES len+1 DIGITS.
138 */
139 static void shl(register digit *p, register int len, register int sh)
140 {
141 register int i;
143 for (i = 0; i < len; i++)
144 p[i] = LHALF(p[i] << sh) | (p[i + 1] >> (HALF_BITS - sh));
145 p[i] = LHALF(p[i] << sh);
146 }
148 /*
149 * __qdivrem(u, v, rem) returns u/v and, optionally, sets *rem to u%v.
150 *
151 * We do this in base 2-sup-HALF_BITS, so that all intermediate products
152 * fit within u_long. As a consequence, the maximum length dividend and
153 * divisor are 4 `digits' in this base (they are shorter if they have
154 * leading zeros).
155 */
156 u64 __qdivrem(u64 uq, u64 vq, u64 *arq)
157 {
158 union uu tmp;
159 digit *u, *v, *q;
160 register digit v1, v2;
161 u_long qhat, rhat, t;
162 int m, n, d, j, i;
163 digit uspace[5], vspace[5], qspace[5];
165 /*
166 * Take care of special cases: divide by zero, and u < v.
167 */
168 if (vq == 0) {
169 /* divide by zero. */
170 static volatile const unsigned int zero = 0;
172 tmp.ul[H] = tmp.ul[L] = 1 / zero;
173 if (arq)
174 *arq = uq;
175 return (tmp.q);
176 }
177 if (uq < vq) {
178 if (arq)
179 *arq = uq;
180 return (0);
181 }
182 u = &uspace[0];
183 v = &vspace[0];
184 q = &qspace[0];
186 /*
187 * Break dividend and divisor into digits in base B, then
188 * count leading zeros to determine m and n. When done, we
189 * will have:
190 * u = (u[1]u[2]...u[m+n]) sub B
191 * v = (v[1]v[2]...v[n]) sub B
192 * v[1] != 0
193 * 1 < n <= 4 (if n = 1, we use a different division algorithm)
194 * m >= 0 (otherwise u < v, which we already checked)
195 * m + n = 4
196 * and thus
197 * m = 4 - n <= 2
198 */
199 tmp.uq = uq;
200 u[0] = 0;
201 u[1] = HHALF(tmp.ul[H]);
202 u[2] = LHALF(tmp.ul[H]);
203 u[3] = HHALF(tmp.ul[L]);
204 u[4] = LHALF(tmp.ul[L]);
205 tmp.uq = vq;
206 v[1] = HHALF(tmp.ul[H]);
207 v[2] = LHALF(tmp.ul[H]);
208 v[3] = HHALF(tmp.ul[L]);
209 v[4] = LHALF(tmp.ul[L]);
210 for (n = 4; v[1] == 0; v++) {
211 if (--n == 1) {
212 u_long rbj; /* r*B+u[j] (not root boy jim) */
213 digit q1, q2, q3, q4;
215 /*
216 * Change of plan, per exercise 16.
217 * r = 0;
218 * for j = 1..4:
219 * q[j] = floor((r*B + u[j]) / v),
220 * r = (r*B + u[j]) % v;
221 * We unroll this completely here.
222 */
223 t = v[2]; /* nonzero, by definition */
224 q1 = u[1] / t;
225 rbj = COMBINE(u[1] % t, u[2]);
226 q2 = rbj / t;
227 rbj = COMBINE(rbj % t, u[3]);
228 q3 = rbj / t;
229 rbj = COMBINE(rbj % t, u[4]);
230 q4 = rbj / t;
231 if (arq)
232 *arq = rbj % t;
233 tmp.ul[H] = COMBINE(q1, q2);
234 tmp.ul[L] = COMBINE(q3, q4);
235 return (tmp.q);
236 }
237 }
239 /*
240 * By adjusting q once we determine m, we can guarantee that
241 * there is a complete four-digit quotient at &qspace[1] when
242 * we finally stop.
243 */
244 for (m = 4 - n; u[1] == 0; u++)
245 m--;
246 for (i = 4 - m; --i >= 0;)
247 q[i] = 0;
248 q += 4 - m;
250 /*
251 * Here we run Program D, translated from MIX to C and acquiring
252 * a few minor changes.
253 *
254 * D1: choose multiplier 1 << d to ensure v[1] >= B/2.
255 */
256 d = 0;
257 for (t = v[1]; t < B / 2; t <<= 1)
258 d++;
259 if (d > 0) {
260 shl(&u[0], m + n, d); /* u <<= d */
261 shl(&v[1], n - 1, d); /* v <<= d */
262 }
263 /*
264 * D2: j = 0.
265 */
266 j = 0;
267 v1 = v[1]; /* for D3 -- note that v[1..n] are constant */
268 v2 = v[2]; /* for D3 */
269 do {
270 register digit uj0, uj1, uj2;
272 /*
273 * D3: Calculate qhat (\^q, in TeX notation).
274 * Let qhat = min((u[j]*B + u[j+1])/v[1], B-1), and
275 * let rhat = (u[j]*B + u[j+1]) mod v[1].
276 * While rhat < B and v[2]*qhat > rhat*B+u[j+2],
277 * decrement qhat and increase rhat correspondingly.
278 * Note that if rhat >= B, v[2]*qhat < rhat*B.
279 */
280 uj0 = u[j + 0]; /* for D3 only -- note that u[j+...] change */
281 uj1 = u[j + 1]; /* for D3 only */
282 uj2 = u[j + 2]; /* for D3 only */
283 if (uj0 == v1) {
284 qhat = B;
285 rhat = uj1;
286 goto qhat_too_big;
287 } else {
288 u_long nn = COMBINE(uj0, uj1);
289 qhat = nn / v1;
290 rhat = nn % v1;
291 }
292 while (v2 * qhat > COMBINE(rhat, uj2)) {
293 qhat_too_big:
294 qhat--;
295 if ((rhat += v1) >= B)
296 break;
297 }
298 /*
299 * D4: Multiply and subtract.
300 * The variable `t' holds any borrows across the loop.
301 * We split this up so that we do not require v[0] = 0,
302 * and to eliminate a final special case.
303 */
304 for (t = 0, i = n; i > 0; i--) {
305 t = u[i + j] - v[i] * qhat - t;
306 u[i + j] = LHALF(t);
307 t = (B - HHALF(t)) & (B - 1);
308 }
309 t = u[j] - t;
310 u[j] = LHALF(t);
311 /*
312 * D5: test remainder.
313 * There is a borrow if and only if HHALF(t) is nonzero;
314 * in that (rare) case, qhat was too large (by exactly 1).
315 * Fix it by adding v[1..n] to u[j..j+n].
316 */
317 if (HHALF(t)) {
318 qhat--;
319 for (t = 0, i = n; i > 0; i--) { /* D6: add back. */
320 t += u[i + j] + v[i];
321 u[i + j] = LHALF(t);
322 t = HHALF(t);
323 }
324 u[j] = LHALF(u[j] + t);
325 }
326 q[j] = qhat;
327 } while (++j <= m); /* D7: loop on j. */
329 /*
330 * If caller wants the remainder, we have to calculate it as
331 * u[m..m+n] >> d (this is at most n digits and thus fits in
332 * u[m+1..m+n], but we may need more source digits).
333 */
334 if (arq) {
335 if (d) {
336 for (i = m + n; i > m; --i)
337 u[i] = (u[i] >> d) |
338 LHALF(u[i - 1] << (HALF_BITS - d));
339 u[i] = 0;
340 }
341 tmp.ul[H] = COMBINE(uspace[1], uspace[2]);
342 tmp.ul[L] = COMBINE(uspace[3], uspace[4]);
343 *arq = tmp.q;
344 }
346 tmp.ul[H] = COMBINE(qspace[1], qspace[2]);
347 tmp.ul[L] = COMBINE(qspace[3], qspace[4]);
348 return (tmp.q);
349 }
351 /*
352 * Divide two signed quads.
353 * Truncates towards zero, as required by C99.
354 */
355 s64 __divdi3(s64 a, s64 b)
356 {
357 u64 ua, ub, uq;
358 int neg = (a < 0) ^ (b < 0);
359 ua = (a < 0) ? -(u64)a : a;
360 ub = (b < 0) ? -(u64)b : b;
361 uq = __qdivrem(ua, ub, (u64 *)0);
362 return (neg ? -uq : uq);
363 }
366 /*
367 * Divide two unsigned quads.
368 */
369 u64 __udivdi3(u64 a, u64 b)
370 {
371 return __qdivrem(a, b, (u64 *)0);
372 }
374 /*
375 * Remainder of unsigned quad division
376 */
377 u64 __umoddi3(u64 a, u64 b)
378 {
379 u64 rem;
380 __qdivrem(a, b, &rem);
381 return rem;
382 }
384 /*
385 * Remainder of signed quad division.
386 * Truncates towards zero, as required by C99:
387 * 11 % 5 = 1
388 * -11 % 5 = -1
389 * 11 % -5 = 1
390 * -11 % -5 = 1
391 */
392 s64 __moddi3(s64 a, s64 b)
393 {
394 u64 ua, ub, urem;
395 int neg = (a < 0);
396 ua = neg ? -(u64)a : a;
397 ub = (b < 0) ? -(u64)b : b;
398 __qdivrem(ua, ub, &urem);
399 return (neg ? -urem : urem);
400 }
402 #endif /* BITS_PER_LONG == 32 */
404 /* Compute with 96 bit intermediate result: (a*b)/c */
405 uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c)
406 {
407 #ifdef __x86_64__
408 asm ( "mul %%rdx; div %%rcx" : "=a" (a) : "0" (a), "d" (b), "c" (c) );
409 return a;
410 #else
411 union {
412 uint64_t ll;
413 struct {
414 #ifdef WORDS_BIGENDIAN
415 uint32_t high, low;
416 #else
417 uint32_t low, high;
418 #endif
419 } l;
420 } u, res;
421 uint64_t rl, rh;
423 u.ll = a;
424 rl = (uint64_t)u.l.low * (uint64_t)b;
425 rh = (uint64_t)u.l.high * (uint64_t)b;
426 rh += (rl >> 32);
427 res.l.high = rh / c;
428 res.l.low = (((rh % c) << 32) + (rl & 0xffffffff)) / c;
429 return res.ll;
430 #endif
431 }
433 unsigned long long parse_size_and_unit(const char *s, const char **ps)
434 {
435 unsigned long long ret;
436 const char *s1;
438 ret = simple_strtoull(s, &s1, 0);
440 switch ( *s1 )
441 {
442 case 'G': case 'g':
443 ret <<= 10;
444 case 'M': case 'm':
445 ret <<= 10;
446 case 'K': case 'k':
447 ret <<= 10;
448 case 'B': case 'b':
449 s1++;
450 break;
451 default:
452 ret <<= 10; /* default to kB */
453 break;
454 }
456 if ( ps != NULL )
457 *ps = s1;
459 return ret;
460 }
462 /*
463 * Local variables:
464 * mode: C
465 * c-set-style: "BSD"
466 * c-basic-offset: 4
467 * tab-width: 4
468 * indent-tabs-mode: nil
469 * End:
470 */