// preparePanic sets up the stack to look like a call to sigpanic.
func (c *sigctxt) preparePanic(sig uint32, gp *g) {
	pc := uintptr(c.eip())
	sp := uintptr(c.esp())

	if shouldPushSigpanic(gp, pc, *(*uintptr)(unsafe.Pointer(sp))) {
		c.pushCall(abi.FuncPCABIInternal(sigpanic), pc)
	} else {
		// Not safe to push the call. Just clobber the frame.
		c.set_eip(uint32(abi.FuncPCABIInternal(sigpanic)))
	}

	sp := uintptr(c.rsp())

	// In case we are panicking from external code, we need to initialize
	// Go special registers. We inject sigpanic0 (instead of sigpanic),
	// which takes care of that.
	if shouldPushSigpanic(gp, pc, *(*uintptr)(unsafe.Pointer(sp))) {
		c.pushCall(abi.FuncPCABI0(sigpanic0), pc)
	} else {
		// Not safe to push the call. Just clobber the frame.
		c.set_rip(uint64(abi.FuncPCABI0(sigpanic0)))
	}
}

	// the stack frame but we're not going back there
	// anyway.
	sp := c.sp() - goarch.PtrSize
	c.set_sp(sp)
	*(*uint64)(unsafe.Pointer(uintptr(sp))) = c.link()

	pc := gp.sigpc

	if shouldPushSigpanic(gp, pc, uintptr(c.link())) {
		// Make it look the like faulting PC called sigpanic.
		c.set_link(uint64(pc))
	}

	// In case we are panicking from external C code
	c.set_r22(uint64(uintptr(unsafe.Pointer(gp))))

	// the stack frame but we're not going back there
	// anyway.
	sp := c.sp() - 4
	c.set_sp(sp)
	*(*uint32)(unsafe.Pointer(uintptr(sp))) = c.lr()

	pc := gp.sigpc

	if shouldPushSigpanic(gp, pc, uintptr(c.lr())) {
		// Make it look the like faulting PC called sigpanic.
		c.set_lr(uint32(pc))
	}

	// In case we are panicking from external C code
	c.set_r10(uint32(uintptr(unsafe.Pointer(gp))))

	// the stack frame but we're not going back there
	// anyway.
	sp := c.sp() - goarch.PtrSize
	c.set_sp(sp)
	*(*uint64)(unsafe.Pointer(uintptr(sp))) = c.ra()

	pc := gp.sigpc

	if shouldPushSigpanic(gp, pc, uintptr(c.ra())) {
		// Make it look the like faulting PC called sigpanic.
		c.set_ra(uint64(pc))
	}

	// In case we are panicking from external C code
	c.set_gp(uint64(uintptr(unsafe.Pointer(gp))))

	// the stack frame but we're not going back there
	// anyway.
	sp := c.sp() - sys.MinFrameSize
	c.set_sp(sp)
	*(*uint32)(unsafe.Pointer(uintptr(sp))) = c.link()

	pc := gp.sigpc

	if shouldPushSigpanic(gp, pc, uintptr(c.link())) {
		// Make it look the like faulting PC called sigpanic.
		c.set_link(uint32(pc))
	}

	// In case we are panicking from external C code
	c.set_r30(uint32(uintptr(unsafe.Pointer(gp))))

	// the stack frame but we're not going back there
	// anyway.
	sp := c.sp() - goarch.PtrSize
	c.set_sp(sp)
	*(*uint64)(unsafe.Pointer(uintptr(sp))) = c.link()

	pc := gp.sigpc

	if shouldPushSigpanic(gp, pc, uintptr(c.link())) {
		// Make it look the like faulting PC called sigpanic.
		c.set_link(uint64(pc))
	}

	// In case we are panicking from external C code

	// sigpanic will save the same frame pointer before calling into a panic
	// function.
	*(*uint64)(unsafe.Pointer(uintptr(sp - goarch.PtrSize))) = c.r29()

	pc := gp.sigpc

	if shouldPushSigpanic(gp, pc, uintptr(c.lr())) {
		// Make it look the like faulting PC called sigpanic.
		c.set_lr(uint64(pc))
	}

	// In case we are panicking from external C code
	c.set_r28(uint64(uintptr(unsafe.Pointer(gp))))

	// the stack frame but we're not going back there
	// anyway.
	sp := c.sp() - sys.MinFrameSize
	c.set_sp(sp)
	*(*uint64)(unsafe.Pointer(uintptr(sp))) = c.link()

	pc := uintptr(gp.sigpc)

	if shouldPushSigpanic(gp, pc, uintptr(c.link())) {
		// Make it look the like faulting PC called sigpanic.
		c.set_link(uint64(pc))
	}

	// In case we are panicking from external C code
	c.set_r0(0)

	// the stack frame but we're not going back there
	// anyway.
	sp := c.sp() - sys.MinFrameSize
	c.set_sp(sp)
	*(*uint64)(unsafe.Pointer(uintptr(sp))) = c.link()

	pc := gp.sigpc

	if shouldPushSigpanic(gp, pc, uintptr(c.link())) {
		// Make it look the like faulting PC called sigpanic.
		c.set_link(uint64(pc))
	}

	// In case we are panicking from external C code
	c.set_r0(0)