>>133
アセンブラ知らね
typedef struct
{
double x, y;
}pos_t;

int is_inside(pos_t P, pos_t A, pos_t B, pos_t C)
{
double alpha, beta, div;
pos_t AB, AC, AP;

AB.x=B.x-A.x;
AB.y=B.y-A.y;
AC.x=C.x-A.x;
AC.y=C.y-A.y;
AP.x=P.x-A.x;
AP.y=P.y-A.y;
div=1.0/(AC.y*AB.x-AC.x*AB.y);
alpha=(AC.y*AP.x-AC.x*AP.y)/div;
beta=(-AB.y*AP.x+AB.x*AP.y)/div;
if(0.0<alpha && alpha<1.0 && 0.0<beta && beta<(1.0-alpha)) return 1;
return 0;
}