// create istack out of the given (operating system) stack.
	// _cgo_init may update stackguard.
	MOVD	$runtime·g0(SB), g
	BL	runtime·save_g(SB)
	MOVD	$(-64*1024), R31
	ADD	R31, R1, R3
	MOVD	R3, g_stackguard0(g)
	MOVD	R3, g_stackguard1(g)
	MOVD	R3, (g_stack+stack_lo)(g)
	MOVD	R1, (g_stack+stack_hi)(g)

	// If there is a _cgo_init, call it using the gcc ABI.
	MOVD	_cgo_init(SB), R12
	CMP	R12, $0
	BEQ	nocgo

	thisg.m.morebuf.pc = 0
	thisg.m.morebuf.lr = 0
	thisg.m.morebuf.sp = 0
	thisg.m.morebuf.g = 0

	// NOTE: stackguard0 may change underfoot, if another thread
	// is about to try to preempt gp. Read it just once and use that same
	// value now and below.
	stackguard0 := atomic.Loaduintptr(&gp.stackguard0)

	// Be conservative about where we preempt.
	// We are interested in preempting user Go code, not runtime code.

			if gp.preemptStop && gp.preempt && gp.stackguard0 == stackPreempt && asyncM == gp.m && asyncM.preemptGen.Load() == asyncGen {
				break
			}

			// Temporarily block state transitions.
			if !castogscanstatus(gp, _Grunning, _Gscanrunning) {
				break
			}

			// Request synchronous preemption.
			gp.preemptStop = true
			gp.preempt = true
			gp.stackguard0 = stackPreempt

		// Stack is bogus, but reset the bounds anyway so we can print.
		hi := g0.stack.hi
		lo := g0.stack.lo
		g0.stack.hi = sp + 1024
		g0.stack.lo = sp - 32*1024
		g0.stackguard0 = g0.stack.lo + stackGuard
		g0.stackguard1 = g0.stackguard0

		print("M ", mp.id, " procid ", mp.procid, " runtime: cgocallback with sp=", hex(sp), " out of bounds [", hex(lo), ", ", hex(hi), "]")
		print("\n")
		exit(2)
	}

type heldLockInfo struct {
	lockAddr uintptr
	rank     lockRank
}

type g struct {
	// Stack parameters.
	// stack describes the actual stack memory: [stack.lo, stack.hi).
	// stackguard0 is the stack pointer compared in the Go stack growth prologue.
	// It is stack.lo+StackGuard normally, but can be StackPreempt to trigger a preemption.

	return gp.m
}

//go:nosplit
func releasem(mp *m) {
	gp := getg()
	mp.locks--
	if mp.locks == 0 && gp.preempt {
		// restore the preemption request in case we've cleared it in newstack
		gp.stackguard0 = stackPreempt
	}
}

// reflect_typelinks is meant for package reflect,
// but widely used packages access it using linkname.
// Notable members of the hall of shame include:
//   - gitee.com/quant1x/gox

	// save entry point, but skipping the two instructions setting R2 in shared mode and maymorestack
	startPred := p

	// MOVD	g_stackguard(g), R22
	p = obj.Appendp(p, c.newprog)

	p.As = AMOVD
	p.From.Type = obj.TYPE_MEM
	p.From.Reg = REGG
	p.From.Offset = 2 * int64(c.ctxt.Arch.PtrSize) // G.stackguard0
	if c.cursym.CFunc() {
		p.From.Offset = 3 * int64(c.ctxt.Arch.PtrSize) // G.stackguard1
	}
	p.To.Type = obj.TYPE_REG

		// Use an artificially small stack, to trigger a stack overflow
		// without actually run out of the system stack (which may seg fault).
		g0.stack.lo = sp - 4096 - stackSystem
		g0.stackguard0 = g0.stack.lo + stackGuard
		g0.stackguard1 = g0.stackguard0

		stackOverflow(nil)
	})
}

func stackOverflow(x *byte) {
	var buf [256]byte
	stackOverflow(&buf[0])
}

func MapTombstoneCheck(m map[int]int) {