_REG_RA
uc.uc_mcontext.__gregs[_REG_RA] = sc->sc_regs[R_RA];
gr[_REG_RA] = (unsigned long) _lwp_exit;
gr[_REG_RA] = (__greg_t)__resumecontext;
gr[_REG_RA] = (unsigned long) _lwp_exit;
gr[_REG_RA] = (uintptr_t) _lwp_exit;
uc.uc_mcontext.__gregs[_REG_RA] = sc->sc_regs[_R_RA];
gr[_REG_RA] = (intptr_t)__resumecontext;
u->uc_mcontext.__gregs[_REG_RA] = (uintptr_t)_lwp_exit; /* RA */
gr[_REG_RA] = (uintptr_t)_resumecontext;