ia64/xen-unstable

view xen/common/lib.c @ 13318:9865145e53eb

[XEN] Skip over the unit in parse_size_and_unit() when returning the remainder
of the string.

Signed-off-by: Ian Campbell <ian.campbell@xensource.com>
author Ian Campbell <ian.campbell@xensource.com>
date Fri Jan 05 18:17:36 2007 +0000 (2007-01-05)
parents 3e2d3d737624
children a8f62eb194e3
line source
2 #include <xen/ctype.h>
3 #include <xen/lib.h>
6 /* for inc/ctype.h */
7 unsigned char _ctype[] = {
8 _C,_C,_C,_C,_C,_C,_C,_C, /* 0-7 */
9 _C,_C|_S,_C|_S,_C|_S,_C|_S,_C|_S,_C,_C, /* 8-15 */
10 _C,_C,_C,_C,_C,_C,_C,_C, /* 16-23 */
11 _C,_C,_C,_C,_C,_C,_C,_C, /* 24-31 */
12 _S|_SP,_P,_P,_P,_P,_P,_P,_P, /* 32-39 */
13 _P,_P,_P,_P,_P,_P,_P,_P, /* 40-47 */
14 _D,_D,_D,_D,_D,_D,_D,_D, /* 48-55 */
15 _D,_D,_P,_P,_P,_P,_P,_P, /* 56-63 */
16 _P,_U|_X,_U|_X,_U|_X,_U|_X,_U|_X,_U|_X,_U, /* 64-71 */
17 _U,_U,_U,_U,_U,_U,_U,_U, /* 72-79 */
18 _U,_U,_U,_U,_U,_U,_U,_U, /* 80-87 */
19 _U,_U,_U,_P,_P,_P,_P,_P, /* 88-95 */
20 _P,_L|_X,_L|_X,_L|_X,_L|_X,_L|_X,_L|_X,_L, /* 96-103 */
21 _L,_L,_L,_L,_L,_L,_L,_L, /* 104-111 */
22 _L,_L,_L,_L,_L,_L,_L,_L, /* 112-119 */
23 _L,_L,_L,_P,_P,_P,_P,_C, /* 120-127 */
24 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* 128-143 */
25 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* 144-159 */
26 _S|_SP,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P, /* 160-175 */
27 _P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P, /* 176-191 */
28 _U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U, /* 192-207 */
29 _U,_U,_U,_U,_U,_U,_U,_P,_U,_U,_U,_U,_U,_U,_U,_L, /* 208-223 */
30 _L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L, /* 224-239 */
31 _L,_L,_L,_L,_L,_L,_L,_P,_L,_L,_L,_L,_L,_L,_L,_L}; /* 240-255 */
34 /* a couple of 64 bit operations ported from freebsd */
36 /*-
37 * Copyright (c) 1992, 1993
38 * The Regents of the University of California. All rights reserved.
39 *
40 * This software was developed by the Computer Systems Engineering group
41 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
42 * contributed to Berkeley.
43 *
44 * Redistribution and use in source and binary forms, with or without
45 * modification, are permitted provided that the following conditions
46 * are met:
47 * 1. Redistributions of source code must retain the above copyright
48 * notice, this list of conditions and the following disclaimer.
49 * 2. Redistributions in binary form must reproduce the above copyright
50 * notice, this list of conditions and the following disclaimer in the
51 * documentation and/or other materials provided with the distribution.
52 * 3. All advertising materials mentioning features or use of this software
53 * must display the following acknowledgement:
54 * This product includes software developed by the University of
55 * California, Berkeley and its contributors.
56 * 4. 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 * $FreeBSD: src/sys/libkern/divdi3.c,v 1.6 1999/08/28 00:46:31 peter Exp $
73 */
75 #include <asm/types.h>
77 #if BITS_PER_LONG == 32
79 /*
80 * Depending on the desired operation, we view a `long long' (aka quad_t) in
81 * one or more of the following formats.
82 */
83 union uu {
84 s64 q; /* as a (signed) quad */
85 s64 uq; /* as an unsigned quad */
86 long sl[2]; /* as two signed longs */
87 unsigned long ul[2]; /* as two unsigned longs */
88 };
89 /* XXX RN: Yuck hardcoded endianess :) */
90 #define _QUAD_HIGHWORD 1
91 #define _QUAD_LOWWORD 0
92 /*
93 * Define high and low longwords.
94 */
95 #define H _QUAD_HIGHWORD
96 #define L _QUAD_LOWWORD
98 /*
99 * Total number of bits in a quad_t and in the pieces that make it up.
100 * These are used for shifting, and also below for halfword extraction
101 * and assembly.
102 */
103 #define CHAR_BIT 8 /* number of bits in a char */
104 #define QUAD_BITS (sizeof(s64) * CHAR_BIT)
105 #define LONG_BITS (sizeof(long) * CHAR_BIT)
106 #define HALF_BITS (sizeof(long) * CHAR_BIT / 2)
108 /*
109 * Extract high and low shortwords from longword, and move low shortword of
110 * longword to upper half of long, i.e., produce the upper longword of
111 * ((quad_t)(x) << (number_of_bits_in_long/2)). (`x' must actually be u_long.)
112 *
113 * These are used in the multiply code, to split a longword into upper
114 * and lower halves, and to reassemble a product as a quad_t, shifted left
115 * (sizeof(long)*CHAR_BIT/2).
116 */
117 #define HHALF(x) ((x) >> HALF_BITS)
118 #define LHALF(x) ((x) & ((1 << HALF_BITS) - 1))
119 #define LHUP(x) ((x) << HALF_BITS)
121 /*
122 * Multiprecision divide. This algorithm is from Knuth vol. 2 (2nd ed),
123 * section 4.3.1, pp. 257--259.
124 */
125 #define B (1 << HALF_BITS) /* digit base */
127 /* Combine two `digits' to make a single two-digit number. */
128 #define COMBINE(a, b) (((u_long)(a) << HALF_BITS) | (b))
130 /* select a type for digits in base B: use unsigned short if they fit */
131 #if ULONG_MAX == 0xffffffff && USHRT_MAX >= 0xffff
132 typedef unsigned short digit;
133 #else
134 typedef u_long digit;
135 #endif
137 /*
138 * Shift p[0]..p[len] left `sh' bits, ignoring any bits that
139 * `fall out' the left (there never will be any such anyway).
140 * We may assume len >= 0. NOTE THAT THIS WRITES len+1 DIGITS.
141 */
142 static void
143 shl(register digit *p, register int len, register int sh)
144 {
145 register int i;
147 for (i = 0; i < len; i++)
148 p[i] = LHALF(p[i] << sh) | (p[i + 1] >> (HALF_BITS - sh));
149 p[i] = LHALF(p[i] << sh);
150 }
152 /*
153 * __qdivrem(u, v, rem) returns u/v and, optionally, sets *rem to u%v.
154 *
155 * We do this in base 2-sup-HALF_BITS, so that all intermediate products
156 * fit within u_long. As a consequence, the maximum length dividend and
157 * divisor are 4 `digits' in this base (they are shorter if they have
158 * leading zeros).
159 */
160 u64
161 __qdivrem(u64 uq, u64 vq, u64 *arq)
162 {
163 union uu tmp;
164 digit *u, *v, *q;
165 register digit v1, v2;
166 u_long qhat, rhat, t;
167 int m, n, d, j, i;
168 digit uspace[5], vspace[5], qspace[5];
170 /*
171 * Take care of special cases: divide by zero, and u < v.
172 */
173 if (vq == 0) {
174 /* divide by zero. */
175 static volatile const unsigned int zero = 0;
177 tmp.ul[H] = tmp.ul[L] = 1 / zero;
178 if (arq)
179 *arq = uq;
180 return (tmp.q);
181 }
182 if (uq < vq) {
183 if (arq)
184 *arq = uq;
185 return (0);
186 }
187 u = &uspace[0];
188 v = &vspace[0];
189 q = &qspace[0];
191 /*
192 * Break dividend and divisor into digits in base B, then
193 * count leading zeros to determine m and n. When done, we
194 * will have:
195 * u = (u[1]u[2]...u[m+n]) sub B
196 * v = (v[1]v[2]...v[n]) sub B
197 * v[1] != 0
198 * 1 < n <= 4 (if n = 1, we use a different division algorithm)
199 * m >= 0 (otherwise u < v, which we already checked)
200 * m + n = 4
201 * and thus
202 * m = 4 - n <= 2
203 */
204 tmp.uq = uq;
205 u[0] = 0;
206 u[1] = HHALF(tmp.ul[H]);
207 u[2] = LHALF(tmp.ul[H]);
208 u[3] = HHALF(tmp.ul[L]);
209 u[4] = LHALF(tmp.ul[L]);
210 tmp.uq = vq;
211 v[1] = HHALF(tmp.ul[H]);
212 v[2] = LHALF(tmp.ul[H]);
213 v[3] = HHALF(tmp.ul[L]);
214 v[4] = LHALF(tmp.ul[L]);
215 for (n = 4; v[1] == 0; v++) {
216 if (--n == 1) {
217 u_long rbj; /* r*B+u[j] (not root boy jim) */
218 digit q1, q2, q3, q4;
220 /*
221 * Change of plan, per exercise 16.
222 * r = 0;
223 * for j = 1..4:
224 * q[j] = floor((r*B + u[j]) / v),
225 * r = (r*B + u[j]) % v;
226 * We unroll this completely here.
227 */
228 t = v[2]; /* nonzero, by definition */
229 q1 = u[1] / t;
230 rbj = COMBINE(u[1] % t, u[2]);
231 q2 = rbj / t;
232 rbj = COMBINE(rbj % t, u[3]);
233 q3 = rbj / t;
234 rbj = COMBINE(rbj % t, u[4]);
235 q4 = rbj / t;
236 if (arq)
237 *arq = rbj % t;
238 tmp.ul[H] = COMBINE(q1, q2);
239 tmp.ul[L] = COMBINE(q3, q4);
240 return (tmp.q);
241 }
242 }
244 /*
245 * By adjusting q once we determine m, we can guarantee that
246 * there is a complete four-digit quotient at &qspace[1] when
247 * we finally stop.
248 */
249 for (m = 4 - n; u[1] == 0; u++)
250 m--;
251 for (i = 4 - m; --i >= 0;)
252 q[i] = 0;
253 q += 4 - m;
255 /*
256 * Here we run Program D, translated from MIX to C and acquiring
257 * a few minor changes.
258 *
259 * D1: choose multiplier 1 << d to ensure v[1] >= B/2.
260 */
261 d = 0;
262 for (t = v[1]; t < B / 2; t <<= 1)
263 d++;
264 if (d > 0) {
265 shl(&u[0], m + n, d); /* u <<= d */
266 shl(&v[1], n - 1, d); /* v <<= d */
267 }
268 /*
269 * D2: j = 0.
270 */
271 j = 0;
272 v1 = v[1]; /* for D3 -- note that v[1..n] are constant */
273 v2 = v[2]; /* for D3 */
274 do {
275 register digit uj0, uj1, uj2;
277 /*
278 * D3: Calculate qhat (\^q, in TeX notation).
279 * Let qhat = min((u[j]*B + u[j+1])/v[1], B-1), and
280 * let rhat = (u[j]*B + u[j+1]) mod v[1].
281 * While rhat < B and v[2]*qhat > rhat*B+u[j+2],
282 * decrement qhat and increase rhat correspondingly.
283 * Note that if rhat >= B, v[2]*qhat < rhat*B.
284 */
285 uj0 = u[j + 0]; /* for D3 only -- note that u[j+...] change */
286 uj1 = u[j + 1]; /* for D3 only */
287 uj2 = u[j + 2]; /* for D3 only */
288 if (uj0 == v1) {
289 qhat = B;
290 rhat = uj1;
291 goto qhat_too_big;
292 } else {
293 u_long nn = COMBINE(uj0, uj1);
294 qhat = nn / v1;
295 rhat = nn % v1;
296 }
297 while (v2 * qhat > COMBINE(rhat, uj2)) {
298 qhat_too_big:
299 qhat--;
300 if ((rhat += v1) >= B)
301 break;
302 }
303 /*
304 * D4: Multiply and subtract.
305 * The variable `t' holds any borrows across the loop.
306 * We split this up so that we do not require v[0] = 0,
307 * and to eliminate a final special case.
308 */
309 for (t = 0, i = n; i > 0; i--) {
310 t = u[i + j] - v[i] * qhat - t;
311 u[i + j] = LHALF(t);
312 t = (B - HHALF(t)) & (B - 1);
313 }
314 t = u[j] - t;
315 u[j] = LHALF(t);
316 /*
317 * D5: test remainder.
318 * There is a borrow if and only if HHALF(t) is nonzero;
319 * in that (rare) case, qhat was too large (by exactly 1).
320 * Fix it by adding v[1..n] to u[j..j+n].
321 */
322 if (HHALF(t)) {
323 qhat--;
324 for (t = 0, i = n; i > 0; i--) { /* D6: add back. */
325 t += u[i + j] + v[i];
326 u[i + j] = LHALF(t);
327 t = HHALF(t);
328 }
329 u[j] = LHALF(u[j] + t);
330 }
331 q[j] = qhat;
332 } while (++j <= m); /* D7: loop on j. */
334 /*
335 * If caller wants the remainder, we have to calculate it as
336 * u[m..m+n] >> d (this is at most n digits and thus fits in
337 * u[m+1..m+n], but we may need more source digits).
338 */
339 if (arq) {
340 if (d) {
341 for (i = m + n; i > m; --i)
342 u[i] = (u[i] >> d) |
343 LHALF(u[i - 1] << (HALF_BITS - d));
344 u[i] = 0;
345 }
346 tmp.ul[H] = COMBINE(uspace[1], uspace[2]);
347 tmp.ul[L] = COMBINE(uspace[3], uspace[4]);
348 *arq = tmp.q;
349 }
351 tmp.ul[H] = COMBINE(qspace[1], qspace[2]);
352 tmp.ul[L] = COMBINE(qspace[3], qspace[4]);
353 return (tmp.q);
354 }
356 /*
357 * Divide two signed quads.
358 * ??? if -1/2 should produce -1 on this machine, this code is wrong
359 * (Grzegorz Milos) Note for the above: -1/2 is 0. And so it should.
360 */
361 s64
362 __divdi3(s64 a, s64 b)
363 {
364 u64 ua, ub, uq;
365 int neg;
367 if (a < 0)
368 ua = -(u64)a, neg = 1;
369 else
370 ua = a, neg = 0;
371 if (b < 0)
372 ub = -(u64)b, neg ^= 1;
373 else
374 ub = b;
375 uq = __qdivrem(ua, ub, (u64 *)0);
376 return (neg ? -uq : uq);
377 }
380 /*
381 * Divide two unsigned quads.
382 */
383 u64
384 __udivdi3(u64 a, u64 b)
385 {
387 return (__qdivrem(a, b, (u64 *)0));
388 }
390 /*
391 * Remainder of unsigned quad division
392 */
393 u64 __umoddi3(u64 a, u64 b)
394 {
395 u64 rem;
396 __qdivrem(a, b, &rem);
397 return rem;
398 }
400 /*
401 * Remainder of signed quad division.
402 * The result of mod is not always equal to division
403 * remainder. The following example shows the result for all
404 * four possible cases:
405 * 11 % 5 = 1
406 * -11 % 5 = 4
407 * 11 % -5 = -4
408 * -11 % -5 = -1
409 */
410 s64 __moddi3(s64 a, s64 b)
411 {
412 u64 ua, ub, urem;
413 int neg1, neg2;
415 if (a < 0)
416 ua = -(u64)a, neg1 = 1;
417 else
418 ua = a, neg1 = 0;
420 if (b < 0)
421 ub = -(u64)b, neg2 = 1;
422 else
423 ub = b, neg2 = 0;
424 __qdivrem(ua, ub, &urem);
426 /* There 4 different cases: */
427 if (neg1) {
428 if (neg2)
429 return -urem;
430 else
431 return ub - urem;
432 } else {
433 if (neg2)
434 return -ub + urem;
435 else
436 return urem;
437 }
438 }
440 #endif /* BITS_PER_LONG == 32 */
442 unsigned long long parse_size_and_unit(const char *s, const char **ps)
443 {
444 unsigned long long ret;
445 const char *s1;
447 ret = simple_strtoull(s, &s1, 0);
449 switch (*s1) {
450 case 'G': case 'g':
451 ret <<= 10;
452 case 'M': case 'm':
453 ret <<= 10;
454 case 'K': case 'k':
455 ret <<= 10;
456 case 'B': case 'b':
457 s1++;
458 break;
459 default:
460 ret <<= 10; /* default to kB */
461 break;
462 }
464 if (ps != NULL)
465 *ps = s1;
467 return ret;
468 }
470 /*
471 * Local variables:
472 * mode: C
473 * c-set-style: "BSD"
474 * c-basic-offset: 8
475 * tab-width: 8
476 * indent-tabs-mode: t
477 * End:
478 */