FC_STACK_DEPTH
pd->pd_d_depth = getpcstack(pd->pd_d_stack, FC_STACK_DEPTH);
pd->pd_w_depth = getpcstack(pd->pd_w_stack, FC_STACK_DEPTH);
pc_t pd_w_stack[FC_STACK_DEPTH];
pc_t pd_d_stack[FC_STACK_DEPTH];