mirror of https://github.com/0intro/conterm
53 lines
792 B
C
53 lines
792 B
C
|
#include "os.h"
|
||
|
|
#include <mp.h>
|
||
|
|
#include "dat.h"
|
||
|
|
|
||
|
|
// diff = abs(b1) - abs(b2), i.e., subtract the magnitudes
|
||
|
|
void
|
||
|
|
mpmagsub(mpint *b1, mpint *b2, mpint *diff)
|
||
|
|
{
|
||
|
|
int n, m, sign;
|
||
|
|
mpint *t;
|
||
|
|
|
||
|
|
// get the sizes right
|
||
|
|
if(mpmagcmp(b1, b2) < 0){
|
||
|
|
sign = -1;
|
||
|
|
t = b1;
|
||
|
|
b1 = b2;
|
||
|
|
b2 = t;
|
||
|
|
} else
|
||
|
|
sign = 1;
|
||
|
|
n = b1->top;
|
||
|
|
m = b2->top;
|
||
|
|
if(m == 0){
|
||
|
|
mpassign(b1, diff);
|
||
|
|
diff->sign = sign;
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
mpbits(diff, n*Dbits);
|
||
|
|
|
||
|
|
mpvecsub(b1->p, n, b2->p, m, diff->p);
|
||
|
|
diff->sign = sign;
|
||
|
|
diff->top = n;
|
||
|
|
mpnorm(diff);
|
||
|
|
}
|
||
|
|
|
||
|
|
// diff = b1 - b2
|
||
|
|
void
|
||
|
|
mpsub(mpint *b1, mpint *b2, mpint *diff)
|
||
|
|
{
|
||
|
|
int sign;
|
||
|
|
|
||
|
|
if(b1->sign != b2->sign){
|
||
|
|
sign = b1->sign;
|
||
|
|
mpmagadd(b1, b2, diff);
|
||
|
|
diff->sign = sign;
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
sign = b1->sign;
|
||
|
|
mpmagsub(b1, b2, diff);
|
||
|
|
if(diff->top != 0)
|
||
|
|
diff->sign *= sign;
|
||
|
|
}
|