108 lines
1.3 KiB
C++
108 lines
1.3 KiB
C++
// Bignum compare
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//
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// returns
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//
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// -1 a < b
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//
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// 0 a = b
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//
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// 1 a > b
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#include "stdafx.h"
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#include "defs.h"
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int
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mcmp(unsigned int *a, unsigned int *b)
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{
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int i;
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if (MSIGN(a) == -1 && MSIGN(b) == 1)
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return -1;
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if (MSIGN(a) == 1 && MSIGN(b) == -1)
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return 1;
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// same sign
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if (MLENGTH(a) < MLENGTH(b)) {
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if (MSIGN(a) == 1)
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return -1;
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else
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return 1;
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}
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if (MLENGTH(a) > MLENGTH(b)) {
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if (MSIGN(a) == 1)
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return 1;
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else
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return -1;
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}
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// same length
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for (i = MLENGTH(a) - 1; i > 0; i--)
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if (a[i] != b[i])
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break;
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if (a[i] < b[i]) {
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if (MSIGN(a) == 1)
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return -1;
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else
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return 1;
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}
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if (a[i] > b[i]) {
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if (MSIGN(a) == 1)
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return 1;
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else
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return -1;
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}
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return 0;
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}
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int
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mcmpint(unsigned int *a, int n)
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{
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int t;
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unsigned int *b;
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b = mint(n);
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t = mcmp(a, b);
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mfree(b);
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return t;
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}
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#if SELFTEST
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void
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test_mcmp(void)
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{
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int i, j, k;
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unsigned int *x, *y;
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logout("testing mcmp\n");
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for (i = -1000; i < 1000; i++) {
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x = mint(i);
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for (j = -1000; j < 1000; j++) {
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y = mint(j);
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k = mcmp(x, y);
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if (i == j && k != 0) {
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logout("failed\n");
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errout();
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}
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if (i < j && k != -1) {
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logout("failed\n");
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errout();
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}
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if (i > j && k != 1) {
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logout("failed\n");
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errout();
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}
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mfree(y);
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}
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mfree(x);
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}
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logout("ok\n");
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}
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#endif
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