编译器抱怨“opcode_table未声明（首次使用此函数）”，为什么？

I have this function:

我有这个功能：

void run(int PC)
{
    int A = 0, op = 0, arg = 0, i = 0;
    char *xpress = NULL, *acode = NULL, strarg[CL_ARG_SIZE];
    while (1)
      {
        printf("PC: %03x | A: %03i |", PC, A);
        op = data[PC]; arg = data[PC+1];
        PC += 2;
        for (i=0 ; i<21 ; ++i)
             if (op == opcode_table[i].op)
             {
                 acode = opcode_table[i].mnemo;
                 sprintf(strarg, "0x%x", arg);   
                 xpress = replace(opcode_table[i].instruct, "_", strarg);
                 break;
              }
         printf(" %s %x\t| %s \t", acode, arg, xpress);
         step();
         exec_instruct(op, arg, &A, &PC);
    }
}
void run(int