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.
	// Always save RA to stack so that panics in leaf

func (c *sigctxt) setsigpc(x uint64) { c.set_pc(x) }

func (c *sigctxt) sigsp() uintptr { return uintptr(c.sp()) }
func (c *sigctxt) siglr() uintptr { return uintptr(c.link()) }

// preparePanic sets up the stack to look like a call to sigpanic.
func (c *sigctxt) preparePanic(sig uint32, gp *g) {
	// We arrange link, and pc to pretend the panicking
	// function calls sigpanic directly.
	// Always save LINK to stack so that panics in leaf

// return PC (pushing a frame for the call). Otherwise, it should be
// left alone so that LR is used as sigpanic's return PC, effectively
// replacing the top-most frame with sigpanic. This is used by
// preparePanic.
func shouldPushSigpanic(gp *g, pc, lr uintptr) bool {
	if pc == 0 {
		// Probably a call to a nil func. The old LR is more
		// useful in the stack trace. Not pushing the frame

		// augmenting the stack frame would break
		// the unwinding code.
		gp.sig = sig
		gp.sigcode0 = uintptr(c.sigcode())
		gp.sigcode1 = c.fault()
		gp.sigpc = c.sigpc()

		c.preparePanic(sig, gp)
		return
	}

	if c.sigFromUser() || flags&_SigNotify != 0 {
		if sigsend(sig) {
			return
		}
	}

	if c.sigFromUser() && signal_ignored(sig) {
		return
	}