ref: a69ae5ed2a33e8d1a62391e57347285228ba4054
dir: /3rd/mp/mpadd.c/
#include "platform.h" // sum = abs(b1) + abs(b2), i.e., add the magnitudes void mpmagadd(mpint *b1, mpint *b2, mpint *sum) { int m, n; mpint *t; sum->flags |= (b1->flags | b2->flags) & MPtimesafe; // get the sizes right if(b2->top > b1->top){ t = b1; b1 = b2; b2 = t; } n = b1->top; m = b2->top; if(n == 0){ mpassign(mpzero, sum); return; } if(m == 0){ mpassign(b1, sum); sum->sign = 1; return; } mpbits(sum, (n+1)*Dbits); sum->top = n+1; mpvecadd(b1->p, n, b2->p, m, sum->p); sum->sign = 1; mpnorm(sum); } // sum = b1 + b2 void mpadd(mpint *b1, mpint *b2, mpint *sum) { int sign; if(b1->sign != b2->sign){ assert(((b1->flags | b2->flags | sum->flags) & MPtimesafe) == 0); if(b1->sign < 0) mpmagsub(b2, b1, sum); else mpmagsub(b1, b2, sum); } else { sign = b1->sign; mpmagadd(b1, b2, sum); if(sum->top != 0) sum->sign = sign; } }