eigenmath/mcmp.cpp

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2004-03-03 21:24:06 +01:00
// Bignum compare
//
// returns
//
// -1 a < b
//
// 0 a = b
//
// 1 a > b
#include "stdafx.h"
#include "defs.h"
int
mcmp(unsigned int *a, unsigned int *b)
{
int i;
if (MSIGN(a) == -1 && MSIGN(b) == 1)
return -1;
if (MSIGN(a) == 1 && MSIGN(b) == -1)
return 1;
// same sign
if (MLENGTH(a) < MLENGTH(b)) {
if (MSIGN(a) == 1)
return -1;
else
return 1;
}
if (MLENGTH(a) > MLENGTH(b)) {
if (MSIGN(a) == 1)
return 1;
else
return -1;
}
// same length
for (i = MLENGTH(a) - 1; i > 0; i--)
if (a[i] != b[i])
break;
if (a[i] < b[i]) {
if (MSIGN(a) == 1)
return -1;
else
return 1;
}
if (a[i] > b[i]) {
if (MSIGN(a) == 1)
return 1;
else
return -1;
}
return 0;
}
int
mcmpint(unsigned int *a, int n)
{
int t;
unsigned int *b;
b = mint(n);
t = mcmp(a, b);
mfree(b);
return t;
}
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#if SELFTEST
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void
test_mcmp(void)
{
int i, j, k;
unsigned int *x, *y;
logout("testing mcmp\n");
for (i = -1000; i < 1000; i++) {
x = mint(i);
for (j = -1000; j < 1000; j++) {
y = mint(j);
k = mcmp(x, y);
if (i == j && k != 0) {
logout("failed\n");
errout();
}
if (i < j && k != -1) {
logout("failed\n");
errout();
}
if (i > j && k != 1) {
logout("failed\n");
errout();
}
mfree(y);
}
mfree(x);
}
logout("ok\n");
}
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#endif