_R_GP
uc.uc_mcontext.__gregs[_REG_GP] = sc->sc_regs[_R_GP];
tf->tf_regs[_R_GP] = (register_t)execp->a.gp_value;
{ "gp", (long *)&ddb_regs.r_regs[_R_GP], DB_SETF_REGS, NULL },
gdb_regs[28] = regs->r_regs[_R_GP]; /* GP */
tf->tf_regs[_R_GP], tf->tf_regs[_R_SP], tf->tf_regs[_R_S8]);