func (c *sigctxt) sigsp() uintptr { return uintptr(c.sp()) }
func (c *sigctxt) siglr() uintptr { return uintptr(c.ra()) }
func (c *sigctxt) fault() uintptr { return uintptr(c.sigaddr()) }

// preparePanic sets up the stack to look like a call to sigpanic.
func (c *sigctxt) preparePanic(sig uint32, gp *g) {
	// We arrange RA, and pc to pretend the panicking
	// function calls sigpanic directly.

		poll.CloseFunc(s)
		return nil, err
	}
	laddr := fd.addrFunc()(lsa)
	raddr := fd.addrFunc()(rsa)
	fd.net = laddr.Network()
	if err := fd.init(); err != nil {
		fd.Close()
		return nil, err
	}
	fd.setAddr(laddr, raddr)
	return fd, nil
}

func fileConn(f *os.File) (Conn, error) {
	fd, err := newFileFD(f)
	if err != nil {
		return nil, err
	}
	switch fd.laddr.(type) {
	case *TCPAddr:

		{regAddr(REG_X6), Yxr},
		{regAddr(REG_X13), Yxr},
		{regAddr(REG_X20), YxrEvex},
		{regAddr(REG_X31), YxrEvex},
		{regAddr(REG_Y0), Yyr},
		{regAddr(REG_Y6), Yyr},
		{regAddr(REG_Y13), Yyr},
		{regAddr(REG_Y20), YyrEvex},
		{regAddr(REG_Y31), YyrEvex},
		{regAddr(REG_Z0), Yzr},
		{regAddr(REG_Z6), Yzr},
		{regAddr(REG_K0), Yk0},
		{regAddr(REG_K5), Yknot0},
		{regAddr(REG_K7), Yknot0},

			Reg:    REG_R0,
			Offset: 0, // panic.argp
		}

		p := s.Func().Text
		p = appendp(p, AMOVD, gpanic, regAddr(REG_R0))

		p = appendp(p, AGet, regAddr(REG_R0))
		p = appendp(p, AI64Eqz)
		p = appendp(p, ANot)
		p = appendp(p, AIf)

		p = appendp(p, AGet, regAddr(REG_SP))
		p = appendp(p, AI64ExtendI32U)
		p = appendp(p, AI64Const, constAddr(framesize+8))
		p = appendp(p, AI64Add)

	sa_flags    uint64
	sa_restorer uintptr
	sa_mask     uint64
}

type siginfoFields struct {
	si_signo int32
	si_errno int32
	si_code  int32
	// below here is a union; si_addr is the only field we use
	si_addr uint64
}

type siginfo struct {
	siginfoFields

	// Pad struct to the max size in the kernel.
	_ [_si_max_size - unsafe.Sizeof(siginfoFields{})]byte
}

	sa_flags    uint64
	sa_restorer uintptr
	sa_mask     uint64
}

type siginfoFields struct {
	si_signo int32
	si_errno int32
	si_code  int32
	// below here is a union; si_addr is the only field we use
	si_addr uint64
}

type siginfo struct {
	siginfoFields

	// Pad struct to the max size in the kernel.
	_ [_si_max_size - unsafe.Sizeof(siginfoFields{})]byte
}

	}
	return syscall.AF_INET6
}

func (a *IPAddr) sockaddr(family int) (syscall.Sockaddr, error) {
	if a == nil {
		return nil, nil
	}
	return ipToSockaddr(family, a.IP, 0, a.Zone)
}

func (a *IPAddr) toLocal(net string) sockaddr {
	return &IPAddr{loopbackIP(net), a.Zone}
}

func (c *IPConn) readFrom(b []byte) (int, *IPAddr, error) {
	// TODO(cw,rsc): consider using readv if we know the family

	sa_flags    uint64
	sa_restorer uintptr
	sa_mask     uint64
}

type siginfoFields struct {
	si_signo int32
	si_errno int32
	si_code  int32
	// below here is a union; si_addr is the only field we use
	si_addr uint64
}

type siginfo struct {
	siginfoFields

	// Pad struct to the max size in the kernel.
	_ [_si_max_size - unsafe.Sizeof(siginfoFields{})]byte
}

	sa_restorer uintptr
}

type siginfoFields struct {
	si_signo int32
	si_errno int32
	si_code  int32
	__pad0   [1]int32
	// below here is a union; si_addr is the only field we use
	si_addr uint64
}

type siginfo struct {
	siginfoFields
	// Pad struct to the max size in the kernel.
	_ [_si_max_size - unsafe.Sizeof(siginfoFields{})]byte
}

type usigset struct {

	sa_restorer uintptr
}

type siginfoFields struct {
	si_signo int32
	si_errno int32
	si_code  int32
	// below here is a union; si_addr is the only field we use
	si_addr uint64
}

type siginfo struct {
	siginfoFields

	// Pad struct to the max size in the kernel.
	_ [_si_max_size - unsafe.Sizeof(siginfoFields{})]byte
}