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[Jnode-svn-commits] SF.net SVN: jnode:[5603] trunk/core/src/core/org/jnode/vm/MathSupport.java
|
From: <ls...@us...> - 2009-07-11 16:46:33
|
Revision: 5603
http://jnode.svn.sourceforge.net/jnode/?rev=5603&view=rev
Author: lsantha
Date: 2009-07-11 16:46:24 +0000 (Sat, 11 Jul 2009)
Log Message:
-----------
Removed deprecated code.
Modified Paths:
--------------
trunk/core/src/core/org/jnode/vm/MathSupport.java
Modified: trunk/core/src/core/org/jnode/vm/MathSupport.java
===================================================================
--- trunk/core/src/core/org/jnode/vm/MathSupport.java 2009-07-11 15:54:31 UTC (rev 5602)
+++ trunk/core/src/core/org/jnode/vm/MathSupport.java 2009-07-11 16:46:24 UTC (rev 5603)
@@ -147,710 +147,4 @@
return -num;
return num;
}
- /*
- private final char[] v = new char[5];
- private final char[] u = new char[5];
- private final char[] q = new char[5];
-
- public static boolean ucmp(//unsigned
- final int a, //unsigned
- final int b) {
- if ((b < 0) && (a >= 0))
- return true;
- if ((b >= 0) && (a < 0))
- return false;
- return a < b;
- }
-
- public static boolean ulcmp(//unsigned
- final long a, //unsigned
- final long b) {
- if ((b < 0L) && (a >= 0L))
- return true;
- if ((b >= 0L) && (a < 0L))
- return false;
- return a < b;
- }
-
- public static //unsigned
- int udiv(//unsigned
- final int a, //unsigned
- final int b) {
- if (b < 0) {
- if (a < 0) {
- if (a >= b)
- return 1;
- }
- return 0;
- }
- if (a >= 0)
- return a / b;
- // hard case
- int a2 = a >>> 1;
- int d = a2 / b;
- int m = ((a2 % b) << 1) + (a & 1);
- return (d << 1) + m / b;
- }
-
- public static //unsigned
- int urem(//unsigned
- final int a, //unsigned
- final int b) {
- if (b < 0) {
- if (a < 0) {
- if (a >= b)
- return a - b;
- }
- return a;
- }
- if (a >= 0)
- return a % b;
- // hard case
- int a2 = a >>> 1;
- int m = ((a2 % b) << 1) + (a & 1);
- return m % b;
- }
-
- public static //unsigned
- long umul(//unsigned
- final int a, //unsigned
- final int b) {
- char a_1 = (char) a;
- char a_2 = (char) (a >> 16);
- char b_1 = (char) b;
- char b_2 = (char) (b >> 16);
- int r1;
- long result = 0L;
- r1 = a_1 * b_1;
- if (r1 < 0) {
- result += Integer.MAX_VALUE;
- r1 -= Integer.MAX_VALUE;
- }
- result += r1;
- r1 = a_2 * b_1;
- if (r1 < 0) {
- result += ((long) Integer.MAX_VALUE) << 16;
- r1 -= Integer.MAX_VALUE;
- }
- result += ((long) r1) << 16;
- r1 = a_1 * b_2;
- if (r1 < 0) {
- result += ((long) Integer.MAX_VALUE) << 16;
- r1 -= Integer.MAX_VALUE;
- }
- result += ((long) r1) << 16;
- return result;
- }
-
- public static long ulmul(long a, long b) {
- char a_1 = (char) a;
- char a_2 = (char) (a >> 16);
- char a_3 = (char) (a >> 32);
- char a_4 = (char) (a >> 48);
- char b_1 = (char) b;
- char b_2 = (char) (b >> 16);
- char b_3 = (char) (b >> 32);
- char b_4 = (char) (b >> 48);
- int r1;
- long result = 0L;
- r1 = a_1 * b_1;
- if (r1 < 0) {
- result += Integer.MAX_VALUE;
- r1 -= Integer.MAX_VALUE;
- }
- result += r1;
- r1 = a_2 * b_1;
- if (r1 < 0) {
- result += ((long) Integer.MAX_VALUE) << 16;
- r1 -= Integer.MAX_VALUE;
- }
- result += ((long) r1) << 16;
- r1 = a_1 * b_2;
- if (r1 < 0) {
- result += ((long) Integer.MAX_VALUE) << 16;
- r1 -= Integer.MAX_VALUE;
- }
- result += ((long) r1) << 16;
- r1 = a_3 * b_1;
- if (r1 < 0) {
- result += ((long) Integer.MAX_VALUE) << 32;
- r1 -= Integer.MAX_VALUE;
- }
- result += ((long) r1) << 32;
- r1 = a_2 * b_2;
- if (r1 < 0) {
- result += ((long) Integer.MAX_VALUE) << 32;
- r1 -= Integer.MAX_VALUE;
- }
- result += ((long) r1) << 32;
- r1 = a_1 * b_3;
- if (r1 < 0) {
- result += ((long) Integer.MAX_VALUE) << 32;
- r1 -= Integer.MAX_VALUE;
- }
- result += ((long) r1) << 32;
- r1 = a_4 * b_1;
- if (r1 < 0) {
- result += ((long) Integer.MAX_VALUE) << 48;
- r1 -= Integer.MAX_VALUE;
- }
- result += ((long) r1) << 48;
- r1 = a_3 * b_2;
- if (r1 < 0) {
- result += ((long) Integer.MAX_VALUE) << 48;
- r1 -= Integer.MAX_VALUE;
- }
- result += ((long) r1) << 48;
- r1 = a_2 * b_3;
- if (r1 < 0) {
- result += ((long) Integer.MAX_VALUE) << 48;
- r1 -= Integer.MAX_VALUE;
- }
- result += ((long) r1) << 48;
- r1 = a_1 * b_4;
- if (r1 < 0) {
- result += ((long) Integer.MAX_VALUE) << 48;
- r1 -= Integer.MAX_VALUE;
- }
- result += ((long) r1) << 48;
- return result;
- }
-
- // ORIGINAL IMPLEMENTATION
- public static long ldiv2(long uq, long vq) {
- boolean neg = false;
- if (uq < 0L) {
- uq = -uq;
- neg = !neg;
- }
- if (vq < 0L) {
- vq = -vq;
- neg = !neg;
- }
- uq = uldivrem(uq, vq, false);
- if (neg)
- uq = -uq;
- return uq;
- }
-
-
- // ORIGINAL IMPLEMENTATION
- public static long lrem2(long uq, long vq) {
- boolean neg = false;
- if (uq < 0L) {
- uq = -uq;
- neg = !neg;
- }
- if (vq < 0L) {
- vq = -vq;
- }
- uq = uldivrem(uq, vq, true);
- if (neg)
- uq = -uq;
- return uq;
- }
-
-
- private static int HHALFQ(final long v) {
- return (int) (v >> 32);
- }
-
- private static int LHALFQ(final long v) {
- return (int) v;
- }
-
- private static char HHALF(final int v) {
- return (char) (v >> 16);
- }
-
- private static char LHALF(final int v) {
- return (char) v;
- }
-
- private static int LHUP(int v) {
- return v << 16;
- }
-
- private static //unsigned
- int COMBINE(final char hi, final char lo) {
- return (hi << 16) | lo;
- }
-
- private static //unsigned
- long COMBINEQ(//unsigned
- final int hi, //unsigned
- final int lo) {
- final long hiL = hi;
- final long loL = lo;
- return (hiL << 32) | (loL & 0xFFFFFFFFL);
- }
-
- private static final int HALF_BITS = 16;
-
- /*
- * Multiprecision divide. This algorithm is from Knuth vol. 2 (2nd ed),
- * section 4.3.1, pp. 257--259.
- *
- * NOTE: the version here is adapted from NetBSD C source code (author unknown).
- *
- private static //unsigned
- long uldivrem(//unsigned
- final long uq, //unsigned
- final long vq, final boolean rem) {
- final int B = 1 << HALF_BITS;
-
- if (vq == 0)
- throw new ArithmeticException("Divide by zero");
- if (ulcmp(uq, vq)) {
- if (rem)
- return uq;
- return 0L;
- }
- /*
- * 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
- *
- char u1 = HHALF(HHALFQ(uq));
- char u2 = LHALF(HHALFQ(uq));
- char u3 = HHALF(LHALFQ(uq));
- char u4 = LHALF(LHALFQ(uq));
-
- final MathSupport mathSupport = VmMagic.currentProcessor().getMathSupport();
- final char[] v = mathSupport.v;
- v[0] = 0;
- v[1] = HHALF(HHALFQ(vq));
- v[2] = LHALF(HHALFQ(vq));
- v[3] = HHALF(LHALFQ(vq));
- v[4] = LHALF(LHALFQ(vq));
- int vi = 0;
- int n;
- for (n = 4; v[vi + 1] == 0; vi++) {
- if (--n == 1) {
- /*unsigned*/
- int rbj; /* r*B+u[j] (not root boy jim) */
-
- /*
- * 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.
- *
- //unsigned
- int t = v[vi + 2]; // nonzero, by definition
- char q1 = (char) udiv(u1, t);
- rbj = COMBINE((char) urem(u1, t), u2);
- char q2 = (char) udiv(rbj, t);
- rbj = COMBINE((char) urem(rbj, t), u3);
- char q3 = (char) udiv(rbj, t);
- rbj = COMBINE((char) urem(rbj, t), u4);
- char q4 = (char) udiv(rbj, t);
- if (rem){
- return urem(rbj, t);
- }
-
- return COMBINEQ(COMBINE(q1, q2), COMBINE(q3, q4));
- }
- }
-
- /*
- * 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.
- *
- final char[] u = mathSupport.u;
- u[0] = 0;
- u[1] = u1;
- u[2] = u2;
- u[3] = u3;
- u[4] = u4;
-
- int ui = 0;
- int m;
- for (m = 4 - n; u[ui + 1] == 0; ++ui)
- m--;
- final char[] q = mathSupport.q;
- /*
- * In Java, q is already initialized to contain 0s.
- * Therefore, the following code is unnecessary.
- * int qi = 0;
- * for (int i = 4 - m; --i >= 0;)
- * q[qi + i] = 0;
- * qi += 4 - m;
- *
- int qi = 4 - m;
-
- /*
- The above note is only true for new arrays, but as this array q
- is reused and therefore it has to reinited to 0
- *
- for (int i = 0; i < q.length; i++) {
- q[i] = 0;
- }
- /*
- * 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.
- *
- int d = 0;
- //unsigned
- for (int t = v[vi + 1]; ucmp(t, B / 2); t <<= 1)
- d++;
- if (d > 0) {
- shl(u, ui, m + n, d); // u <<= d
- shl(v, vi + 1, n - 1, d); // v <<= d
- }
- /*
- * D2: j = 0.
- *
- int j = 0;
- char v1 = v[vi + 1]; // for D3 -- note that v[1..n] are constant
- char v2 = v[vi + 2]; // for D3
- do {
- /*
- * 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.
- *
- char uj0 = u[ui + j + 0]; // for D3 only -- note that u[j+...] change
- char uj1 = u[ui + j + 1]; // for D3 only
- char uj2 = u[ui + j + 2]; // for D3 only
- boolean sim_goto = false;
- //unsigned
- int qhat, rhat;
- if (uj0 == v1) {
- qhat = B;
- rhat = uj1;
- //goto qhat_too_big;
- sim_goto = true;
- } else {
- //unsigned
- int n2 = COMBINE(uj0, uj1);
- qhat = udiv(n2, v1);
- rhat = urem(n2, v1);
- }
- while (
- sim_goto
- || (ucmp(COMBINE((char) rhat, uj2), (int) umul(v2, qhat)))) {
- //qhat_too_big:
- sim_goto = false;
- 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.
- *
- int i;
- //unsigned
- int t;
- for (t = 0, i = n; i > 0; i--) {
- t = u[ui + i + j] - (int) umul(v[vi + i], qhat) - t;
- u[ui + i + j] = LHALF(t);
- t = (B - HHALF(t)) & (B - 1);
- }
- t = u[ui + j] - t;
- u[ui + 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) != 0) {
- qhat--;
- for (t = 0, i = n; i > 0; i--) { // D6: add back.
- t += u[ui + i + j] + v[vi + i];
- u[ui + i + j] = LHALF(t);
- t = HHALF(t);
- }
- u[ui + j] = LHALF(u[ui + j] + t);
- }
- q[qi + j] = (char) 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 (rem) {
- if (d != 0) {
- int i;
- for (i = m + n; i > m; --i)
- u[ui + i] =
- (char) ((u[ui + i] >>> d)
- | LHALF(u[ui + i - 1] << (HALF_BITS - d)));
- u[ui + i] = 0;
- }
- return COMBINEQ(COMBINE(u[1], u[2]), COMBINE(u[3], u[4]));
- }
- return COMBINEQ(COMBINE(q[1], q[2]), COMBINE(q[3], q[4]));
- }
-
- private static void shl(char[] p, int off, int len, int sh) {
- int i;
- for (i = 0; i < len; i++)
- p[off + i] =
- (char) (LHALF(p[off + i] << sh)
- | (p[off + i + 1] >>> (HALF_BITS - sh)));
- p[off + i] = LHALF(p[off + i] << sh);
- }
- */
-
- /* dummy version
- private static long ldiv2(long l1, long l2) {return l1/l2;}
- private static long lrem2(long l1, long l2) {return l1%l2;}
- */
-
- /*
- *
- This method
- does tests
- for
- previously failing
- cases
- *
-
- private static void failing() {
- long l1, l2;
-
- System.out.println("JDK\tNEW\tOLD");
-
- l1 = 843127915674713594l;
- l2 = 1;
- testD(l1, l2);
-
- l1 = 2907146525417257968l;
- l2 = 18;
- testD(l1, l2);
-
- l1 = 5484955353170252401l;
- l2 = 1;
- testR(l1, l2);
-
- l1 = -8074189617124730411l;
- l2 = 13;
- testR(l1, l2);
-
- }
-
- private static void testD(long l1, long l2) {
- System.out.printf("%d\t%d\t%d", l1 / l2, ldiv(l1, l2), ldiv2(l1, l2));
- if ((l1 / l2) == ldiv(l1, l2)) System.out.print(" PASS");
- else System.out.print(" FAIL");
- if ((l1 / l2) == ldiv2(l1, l2)) System.out.print(" PASS");
- else System.out.print(" FAIL");
- System.out.println();
- }
-
- private static void testR(long l1, long l2) {
- System.out.printf("%d\t%d\t%d", l1 % l2, lrem(l1, l2), lrem2(l1, l2));
- if ((l1 % l2) == lrem(l1, l2)) System.out.print(" PASS");
- else System.out.print(" FAIL");
- if ((l1 % l2) == lrem2(l1, l2)) System.out.print(" PASS");
- else System.out.print(" FAIL");
- System.out.println();
- }
-
-
- public static void main(String[] args) {
-
- System.out.println();
-
- failing();
-
- System.out.println();
-
- bench(true);
- bench(false);
-
- Random r = new Random();
-
- long l1 = -5776873939262739814l; // r.nextInt(); // r.nextLong();
- long l2 = 1l; //r.nextInt(50);
-
- System.out.println("l1 = " + l1 + "\nl2 = " + l2 + "\nl1%l2 = " + (l1 % l2));
- System.out.println("Result LREM = " + lrem(l1, l2));
- System.out.println("Result LREM2 = " + lrem2(l1, l2));
-
- l1 = 153;
- l2 = -5;
- System.out.println("l1 = " + l1 + "\nl2 = " + l2 + "\nl1%l2 = " + (l1 % l2));
- System.out.println("Result LREM2 = " + lrem2(l1, l2));
-
- l1 = -154;
- l2 = 5;
- System.out.println("l1 = " + l1 + "\nl2 = " + l2 + "\nl1%l2 = " + (l1 % l2));
- System.out.println("Result LREM2 = " + lrem2(l1, l2));
-
- l1 = 153;
- l2 = 5;
- System.out.println("l1 = " + l1 + "\nl2 = " + l2 + "\nl1%l2 = " + (l1 % l2));
- System.out.println("Result LREM2 = " + lrem2(l1, l2));
-
- l1 = -154;
- l2 = -5;
- System.out.println("l1 = " + l1 + "\nl2 = " + l2 + "\nl1%l2 = " + (l1 % l2));
- System.out.println("Result LREM2 = " + lrem2(l1, l2));
-
- }
-
- static long time(boolean nano) {
- if (nano)
- return System.nanoTime();
- return System.currentTimeMillis();
- }
-
- static final int SIZE = 50000;
- public static long[] random1 = new long[SIZE];
- public static long[] random2 = new long[SIZE];
-
- public static void bench(boolean nano) {
-
- final int REPEAT = 10;
- Random r = new Random();
- long temp, time, sum;
-
- for (int i = 0; i < SIZE; i++) {
- random1[i] = r.nextLong();
- if (random1[i] == 0)
- random1[i] = 1;
- random2[i] = r.nextInt(2000);
- if (random2[i] == 0)
- random2[i] = 1;
- }
-
- System.out.println("DIV:");
-
-
- sum = 0;
- for (int a = 0; a < REPEAT; a++) {
- time = time(nano);
- for (int i = 0; i < SIZE; i++) {
- temp = random1[i] / random2[i];
- }
- final long diff = time(nano) - time;
- sum += diff;
- System.out.print(diff + " ");
- }
- System.out.println("\nJDK = " + (sum));
-
-
- sum = 0;
- for (int a = 0; a < REPEAT; a++) {
- time = time(nano);
- for (int i = 0; i < SIZE; i++) {
- ldiv(random1[i], random2[i]);
- }
- final long diff = time(nano) - time;
- sum += diff;
- System.out.print(diff + " ");
- }
- System.out.println("\nldiv = " + (sum));
-
-
- sum = 0;
- for (int a = 0; a < REPEAT; a++) {
- time = time(nano);
- for (int i = 0; i < SIZE; i++) {
- ldiv2(random1[i], random2[i]);
- }
- final long diff = time(nano) - time;
- sum += diff;
- System.out.print(diff + " ");
- }
- System.out.println("\nldiv2 = " + (sum));
-
-
- System.out.println("\nREM:");
-
-
- sum = 0;
- for (int a = 0; a < REPEAT; a++) {
- time = time(nano);
- for (int i = 0; i < SIZE; i++) {
- temp = random1[i] % random2[i];
- }
- final long diff = time(nano) - time;
- sum += diff;
- System.out.print(diff + " ");
- }
- System.out.println("\nJDK = " + (sum));
-
-
- sum = 0;
- for (int a = 0; a < REPEAT; a++) {
- time = time(nano);
- for (int i = 0; i < SIZE; i++) {
- lrem(random1[i], random2[i]);
- }
- final long diff = time(nano) - time;
- sum += diff;
- System.out.print(diff + " ");
- }
- System.out.println("\nlrem = " + (sum));
-
-
- sum = 0;
- for (int a = 0; a < REPEAT; a++) {
- time = time(nano);
- for (int i = 0; i < SIZE; i++) {
- lrem2(random1[i], random2[i]);
- }
- final long diff = time(nano) - time;
- sum += diff;
- System.out.print(diff + " ");
- }
- System.out.println("\nlrem2 = " + (sum));
-
- // TEST WORKING STATE:
-
- System.out.println("\n\nTest if div and rem are working:\n");
-
- for (int i = 0; i < SIZE; i++) {
- temp = random1[i] / random2[i];
- if (ldiv(random1[i], random2[i]) != temp)
- System.out.println("ERROR FOR LDIV " + random1[i] + " / " + random2[i]);
- if (ldiv2(random1[i], random2[i]) != temp)
- System.out.println("ERROR FOR LDIV2 " + random1[i] + " / " + random2[i]);
- }
-
- for (int i = 0; i < SIZE; i++) {
- temp = random1[i] % random2[i];
- if (lrem(random1[i], random2[i]) != temp)
- System.out.println("ERROR FOR LREM " + random1[i] + " % " + random2[i]);
- if (lrem2(random1[i], random2[i]) != temp)
- System.out.println("ERROR FOR LREM2 " + random1[i] + " % " + random2[i]);
- }
- }
-
- */
-
- // greatest double that can be rounded to an int
- //public static double maxint = (double)Integer.MAX_VALUE;
- // least double that can be rounded to an int
- //public static double minint = (double)Integer.MIN_VALUE;
-
- // greatest double that can be rounded to a long
- //public static double maxlong = (double)Long.MAX_VALUE;
- // least double that can be rounded to a long
- //public static double minlong = (double)Long.MIN_VALUE;
}
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