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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen-unstable] [XEN] Clean up long division code, fix for C99-mandated
# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxxx
# Date 1168721739 0
# Node ID a8f62eb194e3e1cbbcfcb59ed5abd32b73b0e33e
# Parent ba239a4a7c3f25598d7e3f5ee8c03f1d41c94092
[XEN] Clean up long division code, fix for C99-mandated
truncation-towards-zero.
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
---
xen/common/lib.c | 644 +++++++++++++++++++++++++------------------------------
1 files changed, 300 insertions(+), 344 deletions(-)
diff -r ba239a4a7c3f -r a8f62eb194e3 xen/common/lib.c
--- a/xen/common/lib.c Fri Jan 12 17:39:26 2007 +0000
+++ b/xen/common/lib.c Sat Jan 13 20:55:39 2007 +0000
@@ -1,41 +1,44 @@
#include <xen/ctype.h>
#include <xen/lib.h>
-
-
-/* for inc/ctype.h */
+#include <xen/types.h>
+
+/* for ctype.h */
unsigned char _ctype[] = {
-_C,_C,_C,_C,_C,_C,_C,_C, /* 0-7 */
-_C,_C|_S,_C|_S,_C|_S,_C|_S,_C|_S,_C,_C, /* 8-15 */
-_C,_C,_C,_C,_C,_C,_C,_C, /* 16-23 */
-_C,_C,_C,_C,_C,_C,_C,_C, /* 24-31 */
-_S|_SP,_P,_P,_P,_P,_P,_P,_P, /* 32-39 */
-_P,_P,_P,_P,_P,_P,_P,_P, /* 40-47 */
-_D,_D,_D,_D,_D,_D,_D,_D, /* 48-55 */
-_D,_D,_P,_P,_P,_P,_P,_P, /* 56-63 */
-_P,_U|_X,_U|_X,_U|_X,_U|_X,_U|_X,_U|_X,_U, /* 64-71 */
-_U,_U,_U,_U,_U,_U,_U,_U, /* 72-79 */
-_U,_U,_U,_U,_U,_U,_U,_U, /* 80-87 */
-_U,_U,_U,_P,_P,_P,_P,_P, /* 88-95 */
-_P,_L|_X,_L|_X,_L|_X,_L|_X,_L|_X,_L|_X,_L, /* 96-103 */
-_L,_L,_L,_L,_L,_L,_L,_L, /* 104-111 */
-_L,_L,_L,_L,_L,_L,_L,_L, /* 112-119 */
-_L,_L,_L,_P,_P,_P,_P,_C, /* 120-127 */
-0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* 128-143 */
-0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* 144-159 */
-_S|_SP,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P, /* 160-175 */
-_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P, /* 176-191 */
-_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U, /* 192-207 */
-_U,_U,_U,_U,_U,_U,_U,_P,_U,_U,_U,_U,_U,_U,_U,_L, /* 208-223 */
-_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L, /* 224-239 */
-_L,_L,_L,_L,_L,_L,_L,_P,_L,_L,_L,_L,_L,_L,_L,_L}; /* 240-255 */
-
-
-/* a couple of 64 bit operations ported from freebsd */
-
-/*-
+ _C,_C,_C,_C,_C,_C,_C,_C, /* 0-7 */
+ _C,_C|_S,_C|_S,_C|_S,_C|_S,_C|_S,_C,_C, /* 8-15 */
+ _C,_C,_C,_C,_C,_C,_C,_C, /* 16-23 */
+ _C,_C,_C,_C,_C,_C,_C,_C, /* 24-31 */
+ _S|_SP,_P,_P,_P,_P,_P,_P,_P, /* 32-39 */
+ _P,_P,_P,_P,_P,_P,_P,_P, /* 40-47 */
+ _D,_D,_D,_D,_D,_D,_D,_D, /* 48-55 */
+ _D,_D,_P,_P,_P,_P,_P,_P, /* 56-63 */
+ _P,_U|_X,_U|_X,_U|_X,_U|_X,_U|_X,_U|_X,_U, /* 64-71 */
+ _U,_U,_U,_U,_U,_U,_U,_U, /* 72-79 */
+ _U,_U,_U,_U,_U,_U,_U,_U, /* 80-87 */
+ _U,_U,_U,_P,_P,_P,_P,_P, /* 88-95 */
+ _P,_L|_X,_L|_X,_L|_X,_L|_X,_L|_X,_L|_X,_L, /* 96-103 */
+ _L,_L,_L,_L,_L,_L,_L,_L, /* 104-111 */
+ _L,_L,_L,_L,_L,_L,_L,_L, /* 112-119 */
+ _L,_L,_L,_P,_P,_P,_P,_C, /* 120-127 */
+ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* 128-143 */
+ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, /* 144-159 */
+ _S|_SP,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P, /* 160-175 */
+ _P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P,_P, /* 176-191 */
+ _U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U,_U, /* 192-207 */
+ _U,_U,_U,_U,_U,_U,_U,_P,_U,_U,_U,_U,_U,_U,_U,_L, /* 208-223 */
+ _L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L,_L, /* 224-239 */
+ _L,_L,_L,_L,_L,_L,_L,_P,_L,_L,_L,_L,_L,_L,_L,_L}; /* 240-255 */
+
+/*
+ * A couple of 64 bit operations ported from FreeBSD.
+ * The code within the '#if BITS_PER_LONG == 32' block below, and no other
+ * code in this file, is distributed under the following licensing terms
+ * This is the modified '3-clause' BSD license with the obnoxious
+ * advertising clause removed, as permitted by University of California.
+ *
* Copyright (c) 1992, 1993
- * The Regents of the University of California. All rights reserved.
+ * The Regents of the University of California. All rights reserved.
*
* This software was developed by the Computer Systems Engineering group
* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
@@ -49,11 +52,7 @@ _L,_L,_L,_L,_L,_L,_L,_P,_L,_L,_L,_L,_L,_
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- * must display the following acknowledgement:
- * This product includes software developed by the University of
- * California, Berkeley and its contributors.
- * 4. Neither the name of the University nor the names of its contributors
+ * 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
@@ -68,12 +67,7 @@ _L,_L,_L,_L,_L,_L,_L,_P,_L,_L,_L,_L,_L,_
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
- *
- * $FreeBSD: src/sys/libkern/divdi3.c,v 1.6 1999/08/28 00:46:31 peter Exp $
- */
-
-#include <asm/types.h>
-
+ */
#if BITS_PER_LONG == 32
/*
@@ -81,10 +75,10 @@ _L,_L,_L,_L,_L,_L,_L,_P,_L,_L,_L,_L,_L,_
* one or more of the following formats.
*/
union uu {
- s64 q; /* as a (signed) quad */
- s64 uq; /* as an unsigned quad */
- long sl[2]; /* as two signed longs */
- unsigned long ul[2]; /* as two unsigned longs */
+ s64 q; /* as a (signed) quad */
+ s64 uq; /* as an unsigned quad */
+ long sl[2]; /* as two signed longs */
+ unsigned long ul[2]; /* as two unsigned longs */
};
/* XXX RN: Yuck hardcoded endianess :) */
#define _QUAD_HIGHWORD 1
@@ -122,31 +116,26 @@ union uu {
* Multiprecision divide. This algorithm is from Knuth vol. 2 (2nd ed),
* section 4.3.1, pp. 257--259.
*/
-#define B (1 << HALF_BITS) /* digit base */
+#define B (1 << HALF_BITS) /* digit base */
/* Combine two `digits' to make a single two-digit number. */
-#define COMBINE(a, b) (((u_long)(a) << HALF_BITS) | (b))
-
-/* select a type for digits in base B: use unsigned short if they fit */
-#if ULONG_MAX == 0xffffffff && USHRT_MAX >= 0xffff
-typedef unsigned short digit;
-#else
+#define COMBINE(a, b) (((u_long)(a) << HALF_BITS) | (b))
+
+/* select a type for digits in base B */
typedef u_long digit;
-#endif
/*
* Shift p[0]..p[len] left `sh' bits, ignoring any bits that
* `fall out' the left (there never will be any such anyway).
* We may assume len >= 0. NOTE THAT THIS WRITES len+1 DIGITS.
*/
-static void
-shl(register digit *p, register int len, register int sh)
-{
- register int i;
-
- for (i = 0; i < len; i++)
- p[i] = LHALF(p[i] << sh) | (p[i + 1] >> (HALF_BITS - sh));
- p[i] = LHALF(p[i] << sh);
+static void shl(register digit *p, register int len, register int sh)
+{
+ register int i;
+
+ for (i = 0; i < len; i++)
+ p[i] = LHALF(p[i] << sh) | (p[i + 1] >> (HALF_BITS - sh));
+ p[i] = LHALF(p[i] << sh);
}
/*
@@ -157,234 +146,222 @@ shl(register digit *p, register int len,
* divisor are 4 `digits' in this base (they are shorter if they have
* leading zeros).
*/
-u64
-__qdivrem(u64 uq, u64 vq, u64 *arq)
-{
- union uu tmp;
- digit *u, *v, *q;
- register digit v1, v2;
- u_long qhat, rhat, t;
- int m, n, d, j, i;
- digit uspace[5], vspace[5], qspace[5];
-
- /*
- * Take care of special cases: divide by zero, and u < v.
- */
- if (vq == 0) {
- /* divide by zero. */
- static volatile const unsigned int zero = 0;
-
- tmp.ul[H] = tmp.ul[L] = 1 / zero;
- if (arq)
- *arq = uq;
- return (tmp.q);
- }
- if (uq < vq) {
- if (arq)
- *arq = uq;
- return (0);
- }
- u = &uspace[0];
- v = &vspace[0];
- q = &qspace[0];
-
- /*
- * Break dividend and divisor into digits in base B, then
- * count leading zeros to determine m and n. When done, we
- * will have:
- * u = (u[1]u[2]...u[m+n]) sub B
- * v = (v[1]v[2]...v[n]) sub B
- * v[1] != 0
- * 1 < n <= 4 (if n = 1, we use a different division algorithm)
- * m >= 0 (otherwise u < v, which we already checked)
- * m + n = 4
- * and thus
- * m = 4 - n <= 2
- */
- tmp.uq = uq;
- u[0] = 0;
- u[1] = HHALF(tmp.ul[H]);
- u[2] = LHALF(tmp.ul[H]);
- u[3] = HHALF(tmp.ul[L]);
- u[4] = LHALF(tmp.ul[L]);
- tmp.uq = vq;
- v[1] = HHALF(tmp.ul[H]);
- v[2] = LHALF(tmp.ul[H]);
- v[3] = HHALF(tmp.ul[L]);
- v[4] = LHALF(tmp.ul[L]);
- for (n = 4; v[1] == 0; v++) {
- if (--n == 1) {
- u_long rbj; /* r*B+u[j] (not root boy jim) */
- digit q1, q2, q3, q4;
-
- /*
- * Change of plan, per exercise 16.
- * r = 0;
- * for j = 1..4:
- * q[j] = floor((r*B + u[j]) / v),
- * r = (r*B + u[j]) % v;
- * We unroll this completely here.
- */
- t = v[2]; /* nonzero, by definition */
- q1 = u[1] / t;
- rbj = COMBINE(u[1] % t, u[2]);
- q2 = rbj / t;
- rbj = COMBINE(rbj % t, u[3]);
- q3 = rbj / t;
- rbj = COMBINE(rbj % t, u[4]);
- q4 = rbj / t;
- if (arq)
- *arq = rbj % t;
- tmp.ul[H] = COMBINE(q1, q2);
- tmp.ul[L] = COMBINE(q3, q4);
- return (tmp.q);
- }
- }
-
- /*
- * By adjusting q once we determine m, we can guarantee that
- * there is a complete four-digit quotient at &qspace[1] when
- * we finally stop.
- */
- for (m = 4 - n; u[1] == 0; u++)
- m--;
- for (i = 4 - m; --i >= 0;)
- q[i] = 0;
- q += 4 - m;
-
- /*
- * Here we run Program D, translated from MIX to C and acquiring
- * a few minor changes.
- *
- * D1: choose multiplier 1 << d to ensure v[1] >= B/2.
- */
- d = 0;
- for (t = v[1]; t < B / 2; t <<= 1)
- d++;
- if (d > 0) {
- shl(&u[0], m + n, d); /* u <<= d */
- shl(&v[1], n - 1, d); /* v <<= d */
- }
- /*
- * D2: j = 0.
- */
- j = 0;
- v1 = v[1]; /* for D3 -- note that v[1..n] are constant */
- v2 = v[2]; /* for D3 */
- do {
- register digit uj0, uj1, uj2;
-
- /*
- * D3: Calculate qhat (\^q, in TeX notation).
- * Let qhat = min((u[j]*B + u[j+1])/v[1], B-1), and
- * let rhat = (u[j]*B + u[j+1]) mod v[1].
- * While rhat < B and v[2]*qhat > rhat*B+u[j+2],
- * decrement qhat and increase rhat correspondingly.
- * Note that if rhat >= B, v[2]*qhat < rhat*B.
- */
- uj0 = u[j + 0]; /* for D3 only -- note that u[j+...] change */
- uj1 = u[j + 1]; /* for D3 only */
- uj2 = u[j + 2]; /* for D3 only */
- if (uj0 == v1) {
- qhat = B;
- rhat = uj1;
- goto qhat_too_big;
- } else {
- u_long nn = COMBINE(uj0, uj1);
- qhat = nn / v1;
- rhat = nn % v1;
- }
- while (v2 * qhat > COMBINE(rhat, uj2)) {
- qhat_too_big:
- qhat--;
- if ((rhat += v1) >= B)
- break;
- }
- /*
- * D4: Multiply and subtract.
- * The variable `t' holds any borrows across the loop.
- * We split this up so that we do not require v[0] = 0,
- * and to eliminate a final special case.
- */
- for (t = 0, i = n; i > 0; i--) {
- t = u[i + j] - v[i] * qhat - t;
- u[i + j] = LHALF(t);
- t = (B - HHALF(t)) & (B - 1);
- }
- t = u[j] - t;
- u[j] = LHALF(t);
- /*
- * D5: test remainder.
- * There is a borrow if and only if HHALF(t) is nonzero;
- * in that (rare) case, qhat was too large (by exactly 1).
- * Fix it by adding v[1..n] to u[j..j+n].
- */
- if (HHALF(t)) {
- qhat--;
- for (t = 0, i = n; i > 0; i--) { /* D6: add back. */
- t += u[i + j] + v[i];
- u[i + j] = LHALF(t);
- t = HHALF(t);
- }
- u[j] = LHALF(u[j] + t);
- }
- q[j] = qhat;
- } while (++j <= m); /* D7: loop on j. */
-
- /*
- * If caller wants the remainder, we have to calculate it as
- * u[m..m+n] >> d (this is at most n digits and thus fits in
- * u[m+1..m+n], but we may need more source digits).
- */
- if (arq) {
- if (d) {
- for (i = m + n; i > m; --i)
- u[i] = (u[i] >> d) |
- LHALF(u[i - 1] << (HALF_BITS - d));
- u[i] = 0;
- }
- tmp.ul[H] = COMBINE(uspace[1], uspace[2]);
- tmp.ul[L] = COMBINE(uspace[3], uspace[4]);
- *arq = tmp.q;
- }
-
- tmp.ul[H] = COMBINE(qspace[1], qspace[2]);
- tmp.ul[L] = COMBINE(qspace[3], qspace[4]);
- return (tmp.q);
+u64 __qdivrem(u64 uq, u64 vq, u64 *arq)
+{
+ union uu tmp;
+ digit *u, *v, *q;
+ register digit v1, v2;
+ u_long qhat, rhat, t;
+ int m, n, d, j, i;
+ digit uspace[5], vspace[5], qspace[5];
+
+ /*
+ * Take care of special cases: divide by zero, and u < v.
+ */
+ if (vq == 0) {
+ /* divide by zero. */
+ static volatile const unsigned int zero = 0;
+
+ tmp.ul[H] = tmp.ul[L] = 1 / zero;
+ if (arq)
+ *arq = uq;
+ return (tmp.q);
+ }
+ if (uq < vq) {
+ if (arq)
+ *arq = uq;
+ return (0);
+ }
+ u = &uspace[0];
+ v = &vspace[0];
+ q = &qspace[0];
+
+ /*
+ * Break dividend and divisor into digits in base B, then
+ * count leading zeros to determine m and n. When done, we
+ * will have:
+ * u = (u[1]u[2]...u[m+n]) sub B
+ * v = (v[1]v[2]...v[n]) sub B
+ * v[1] != 0
+ * 1 < n <= 4 (if n = 1, we use a different division algorithm)
+ * m >= 0 (otherwise u < v, which we already checked)
+ * m + n = 4
+ * and thus
+ * m = 4 - n <= 2
+ */
+ tmp.uq = uq;
+ u[0] = 0;
+ u[1] = HHALF(tmp.ul[H]);
+ u[2] = LHALF(tmp.ul[H]);
+ u[3] = HHALF(tmp.ul[L]);
+ u[4] = LHALF(tmp.ul[L]);
+ tmp.uq = vq;
+ v[1] = HHALF(tmp.ul[H]);
+ v[2] = LHALF(tmp.ul[H]);
+ v[3] = HHALF(tmp.ul[L]);
+ v[4] = LHALF(tmp.ul[L]);
+ for (n = 4; v[1] == 0; v++) {
+ if (--n == 1) {
+ u_long rbj; /* r*B+u[j] (not root boy jim) */
+ digit q1, q2, q3, q4;
+
+ /*
+ * Change of plan, per exercise 16.
+ * r = 0;
+ * for j = 1..4:
+ * q[j] = floor((r*B + u[j]) / v),
+ * r = (r*B + u[j]) % v;
+ * We unroll this completely here.
+ */
+ t = v[2]; /* nonzero, by definition */
+ q1 = u[1] / t;
+ rbj = COMBINE(u[1] % t, u[2]);
+ q2 = rbj / t;
+ rbj = COMBINE(rbj % t, u[3]);
+ q3 = rbj / t;
+ rbj = COMBINE(rbj % t, u[4]);
+ q4 = rbj / t;
+ if (arq)
+ *arq = rbj % t;
+ tmp.ul[H] = COMBINE(q1, q2);
+ tmp.ul[L] = COMBINE(q3, q4);
+ return (tmp.q);
+ }
+ }
+
+ /*
+ * By adjusting q once we determine m, we can guarantee that
+ * there is a complete four-digit quotient at &qspace[1] when
+ * we finally stop.
+ */
+ for (m = 4 - n; u[1] == 0; u++)
+ m--;
+ for (i = 4 - m; --i >= 0;)
+ q[i] = 0;
+ q += 4 - m;
+
+ /*
+ * Here we run Program D, translated from MIX to C and acquiring
+ * a few minor changes.
+ *
+ * D1: choose multiplier 1 << d to ensure v[1] >= B/2.
+ */
+ d = 0;
+ for (t = v[1]; t < B / 2; t <<= 1)
+ d++;
+ if (d > 0) {
+ shl(&u[0], m + n, d); /* u <<= d */
+ shl(&v[1], n - 1, d); /* v <<= d */
+ }
+ /*
+ * D2: j = 0.
+ */
+ j = 0;
+ v1 = v[1]; /* for D3 -- note that v[1..n] are constant */
+ v2 = v[2]; /* for D3 */
+ do {
+ register digit uj0, uj1, uj2;
+
+ /*
+ * D3: Calculate qhat (\^q, in TeX notation).
+ * Let qhat = min((u[j]*B + u[j+1])/v[1], B-1), and
+ * let rhat = (u[j]*B + u[j+1]) mod v[1].
+ * While rhat < B and v[2]*qhat > rhat*B+u[j+2],
+ * decrement qhat and increase rhat correspondingly.
+ * Note that if rhat >= B, v[2]*qhat < rhat*B.
+ */
+ uj0 = u[j + 0]; /* for D3 only -- note that u[j+...] change */
+ uj1 = u[j + 1]; /* for D3 only */
+ uj2 = u[j + 2]; /* for D3 only */
+ if (uj0 == v1) {
+ qhat = B;
+ rhat = uj1;
+ goto qhat_too_big;
+ } else {
+ u_long nn = COMBINE(uj0, uj1);
+ qhat = nn / v1;
+ rhat = nn % v1;
+ }
+ while (v2 * qhat > COMBINE(rhat, uj2)) {
+ qhat_too_big:
+ qhat--;
+ if ((rhat += v1) >= B)
+ break;
+ }
+ /*
+ * D4: Multiply and subtract.
+ * The variable `t' holds any borrows across the loop.
+ * We split this up so that we do not require v[0] = 0,
+ * and to eliminate a final special case.
+ */
+ for (t = 0, i = n; i > 0; i--) {
+ t = u[i + j] - v[i] * qhat - t;
+ u[i + j] = LHALF(t);
+ t = (B - HHALF(t)) & (B - 1);
+ }
+ t = u[j] - t;
+ u[j] = LHALF(t);
+ /*
+ * D5: test remainder.
+ * There is a borrow if and only if HHALF(t) is nonzero;
+ * in that (rare) case, qhat was too large (by exactly 1).
+ * Fix it by adding v[1..n] to u[j..j+n].
+ */
+ if (HHALF(t)) {
+ qhat--;
+ for (t = 0, i = n; i > 0; i--) { /* D6: add back. */
+ t += u[i + j] + v[i];
+ u[i + j] = LHALF(t);
+ t = HHALF(t);
+ }
+ u[j] = LHALF(u[j] + t);
+ }
+ q[j] = qhat;
+ } while (++j <= m); /* D7: loop on j. */
+
+ /*
+ * If caller wants the remainder, we have to calculate it as
+ * u[m..m+n] >> d (this is at most n digits and thus fits in
+ * u[m+1..m+n], but we may need more source digits).
+ */
+ if (arq) {
+ if (d) {
+ for (i = m + n; i > m; --i)
+ u[i] = (u[i] >> d) |
+ LHALF(u[i - 1] << (HALF_BITS - d));
+ u[i] = 0;
+ }
+ tmp.ul[H] = COMBINE(uspace[1], uspace[2]);
+ tmp.ul[L] = COMBINE(uspace[3], uspace[4]);
+ *arq = tmp.q;
+ }
+
+ tmp.ul[H] = COMBINE(qspace[1], qspace[2]);
+ tmp.ul[L] = COMBINE(qspace[3], qspace[4]);
+ return (tmp.q);
}
/*
* Divide two signed quads.
- * ??? if -1/2 should produce -1 on this machine, this code is wrong
- * (Grzegorz Milos) Note for the above: -1/2 is 0. And so it should.
- */
-s64
-__divdi3(s64 a, s64 b)
-{
- u64 ua, ub, uq;
- int neg;
-
- if (a < 0)
- ua = -(u64)a, neg = 1;
- else
- ua = a, neg = 0;
- if (b < 0)
- ub = -(u64)b, neg ^= 1;
- else
- ub = b;
- uq = __qdivrem(ua, ub, (u64 *)0);
- return (neg ? -uq : uq);
+ * Truncates towards zero, as required by C99.
+ */
+s64 __divdi3(s64 a, s64 b)
+{
+ u64 ua, ub, uq;
+ int neg = (a < 0) ^ (b < 0);
+ ua = (a < 0) ? -(u64)a : a;
+ ub = (b < 0) ? -(u64)b : b;
+ uq = __qdivrem(ua, ub, (u64 *)0);
+ return (neg ? -uq : uq);
}
/*
* Divide two unsigned quads.
*/
-u64
-__udivdi3(u64 a, u64 b)
-{
-
- return (__qdivrem(a, b, (u64 *)0));
+u64 __udivdi3(u64 a, u64 b)
+{
+ return __qdivrem(a, b, (u64 *)0);
}
/*
@@ -392,87 +369,66 @@ __udivdi3(u64 a, u64 b)
*/
u64 __umoddi3(u64 a, u64 b)
{
- u64 rem;
- __qdivrem(a, b, &rem);
- return rem;
+ u64 rem;
+ __qdivrem(a, b, &rem);
+ return rem;
}
/*
* Remainder of signed quad division.
- * The result of mod is not always equal to division
- * remainder. The following example shows the result for all
- * four possible cases:
+ * Truncates towards zero, as required by C99:
* 11 % 5 = 1
- * -11 % 5 = 4
- * 11 % -5 = -4
- * -11 % -5 = -1
+ * -11 % 5 = -1
+ * 11 % -5 = 1
+ * -11 % -5 = 1
*/
s64 __moddi3(s64 a, s64 b)
{
- u64 ua, ub, urem;
- int neg1, neg2;
-
- if (a < 0)
- ua = -(u64)a, neg1 = 1;
- else
- ua = a, neg1 = 0;
-
- if (b < 0)
- ub = -(u64)b, neg2 = 1;
- else
- ub = b, neg2 = 0;
- __qdivrem(ua, ub, &urem);
-
- /* There 4 different cases: */
- if (neg1) {
- if (neg2)
- return -urem;
- else
- return ub - urem;
- } else {
- if (neg2)
- return -ub + urem;
- else
- return urem;
- }
+ u64 ua, ub, urem;
+ int neg = (a < 0);
+ ua = neg ? -(u64)a : a;
+ ub = (b < 0) ? -(u64)b : b;
+ __qdivrem(ua, ub, &urem);
+ return (neg ? -urem : urem);
}
#endif /* BITS_PER_LONG == 32 */
unsigned long long parse_size_and_unit(const char *s, const char **ps)
{
- unsigned long long ret;
- const char *s1;
-
- ret = simple_strtoull(s, &s1, 0);
-
- switch (*s1) {
- case 'G': case 'g':
- ret <<= 10;
- case 'M': case 'm':
- ret <<= 10;
- case 'K': case 'k':
- ret <<= 10;
- case 'B': case 'b':
- s1++;
- break;
- default:
- ret <<= 10; /* default to kB */
- break;
- }
-
- if (ps != NULL)
- *ps = s1;
-
- return ret;
+ unsigned long long ret;
+ const char *s1;
+
+ ret = simple_strtoull(s, &s1, 0);
+
+ switch ( *s1 )
+ {
+ case 'G': case 'g':
+ ret <<= 10;
+ case 'M': case 'm':
+ ret <<= 10;
+ case 'K': case 'k':
+ ret <<= 10;
+ case 'B': case 'b':
+ s1++;
+ break;
+ default:
+ ret <<= 10; /* default to kB */
+ break;
+ }
+
+ if ( ps != NULL )
+ *ps = s1;
+
+ return ret;
}
/*
* Local variables:
* mode: C
* c-set-style: "BSD"
- * c-basic-offset: 8
- * tab-width: 8
- * indent-tabs-mode: t
+ * c-basic-offset: 4
+ * tab-width: 4
+ * indent-tabs-mode: nil
* End:
*/
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