mpadd.c (792B)
1 #include "os.h" 2 #include <mp.h> 3 #include "dat.h" 4 5 /* sum = abs(b1) + abs(b2), i.e., add the magnitudes */ 6 void 7 mpmagadd(mpint *b1, mpint *b2, mpint *sum) 8 { 9 int m, n; 10 mpint *t; 11 12 /* get the sizes right */ 13 if(b2->top > b1->top){ 14 t = b1; 15 b1 = b2; 16 b2 = t; 17 } 18 n = b1->top; 19 m = b2->top; 20 if(n == 0){ 21 mpassign(mpzero, sum); 22 return; 23 } 24 if(m == 0){ 25 mpassign(b1, sum); 26 return; 27 } 28 mpbits(sum, (n+1)*Dbits); 29 sum->top = n+1; 30 31 mpvecadd(b1->p, n, b2->p, m, sum->p); 32 sum->sign = 1; 33 34 mpnorm(sum); 35 } 36 37 /* sum = b1 + b2 */ 38 void 39 mpadd(mpint *b1, mpint *b2, mpint *sum) 40 { 41 int sign; 42 43 if(b1->sign != b2->sign){ 44 if(b1->sign < 0) 45 mpmagsub(b2, b1, sum); 46 else 47 mpmagsub(b1, b2, sum); 48 } else { 49 sign = b1->sign; 50 mpmagadd(b1, b2, sum); 51 if(sum->top != 0) 52 sum->sign = sign; 53 } 54 }