USER_REGS
struct trapframe *tf = (struct trapframe *)USER_REGS(p);
regs = USER_REGS(p);
bcopy((caddr_t)USER_REGS(p), (caddr_t)regs, sizeof(struct reg));
struct reg *procregs = (struct reg *)USER_REGS(p);
tf = (struct trapframe *)USER_REGS(p);
struct reg *sstf = USER_REGS(p);
p2->p_md.md_tf = (struct trapframe *)USER_REGS(p2);
USER_REGS(p2)->r[31] = (u_int)stack;
USER_REGS(p2)->r[27] = (u_int)tcb;