osigframe
struct osigframe sf, *fp;
fp = (struct osigframe *)((uintptr_t)td->td_sigstk.ss_sp +
td->td_sigstk.ss_size - sizeof(struct osigframe));
fp = (struct osigframe *)regs->tf_esp - 1;
ASSYM(SIGF_SC, offsetof(struct osigframe, sf_siginfo.si_sc));