55 lines
783 B
C
55 lines
783 B
C
#include "os.h"
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#include <mp.h>
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#include "dat.h"
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// sum = abs(b1) + abs(b2), i.e., add the magnitudes
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void
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mpmagadd(mpint *b1, mpint *b2, mpint *sum)
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{
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int m, n;
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mpint *t;
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// get the sizes right
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if(b2->top > b1->top){
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t = b1;
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b1 = b2;
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b2 = t;
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}
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n = b1->top;
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m = b2->top;
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if(n == 0){
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mpassign(mpzero, sum);
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return;
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}
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if(m == 0){
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mpassign(b1, sum);
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return;
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}
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mpbits(sum, (n+1)*Dbits);
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sum->top = n+1;
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mpvecadd(b1->p, n, b2->p, m, sum->p);
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sum->sign = 1;
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mpnorm(sum);
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}
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// sum = b1 + b2
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void
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mpadd(mpint *b1, mpint *b2, mpint *sum)
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{
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int sign;
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if(b1->sign != b2->sign){
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if(b1->sign < 0)
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mpmagsub(b2, b1, sum);
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else
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mpmagsub(b1, b2, sum);
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} else {
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sign = b1->sign;
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mpmagadd(b1, b2, sum);
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if(sum->top != 0)
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sum->sign = sign;
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}
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}
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