// escape analysis result. The test is cheaper than the call.
var cgoAlwaysFalse bool

var cgo_yield = &_cgo_yield

func cgoNoCallback(v bool) {
	g := getg()
	if g.nocgocallback && v {
		panic("runtime: unexpected setting cgoNoCallback")
	}
	g.nocgocallback = v

// stack and outside the $GOMAXPROCS limit. crosscall2 calls
// runtime.cgocallback(_cgoexp_GoF, frame, ctxt) using the gc ABI.
// (crosscall2's framesize argument is no longer used, but there's one
// case where SWIG calls crosscall2 directly and expects to pass this
// argument. See _cgo_panic.)
//
// runtime.cgocallback (in asm_$GOARCH.s) switches from m.g0's stack
// to the original g (m.curg)'s stack, on which it calls

	// Used by the execution tracer.
	inMarkAssist bool
	coroexit     bool // argument to coroswitch_m

	raceignore    int8  // ignore race detection events
	nocgocallback bool  // whether disable callback from C
	tracking      bool  // whether we're tracking this G for sched latency statistics
	trackingSeq   uint8 // used to decide whether to track this G

func noEscapePtr[T any](p *T) *T {
	x := uintptr(unsafe.Pointer(p))
	return (*T)(unsafe.Pointer(x ^ 0))
}

// Not all cgocallback frames are actually cgocallback,
// so not all have these arguments. Mark them uintptr so that the GC
// does not misinterpret memory when the arguments are not present.
// cgocallback is not called from Go, only from crosscall2.
// This in turn calls cgocallbackg, which is where we'll find

	JAL	runtime·save_g(SB)
	MOVV	(g_stack+stack_hi)(g), R5
	MOVV	8(R3), R6
	SUBVU	R6, R5
	MOVV	R5, R3

	MOVW	R4, ret+16(FP)
	RET

// func cgocallback(fn, frame unsafe.Pointer, ctxt uintptr)
// See cgocall.go for more details.
TEXT ·cgocallback(SB),NOSPLIT,$24-24
	NO_LOCAL_POINTERS

	// Skip cgocallbackg, just dropm when fn is nil, and frame is the saved g.
	// It is used to dropm while thread is exiting.

	XOR	R0, R0

	MOVD	asmcgocallSaveOffset(R1), R1	// Restore stack pointer.
#ifndef GOOS_aix
	MOVD	24(R1), R2
#endif
	// ret = R3
	RET

// func cgocallback(fn, frame unsafe.Pointer, ctxt uintptr)
// See cgocall.go for more details.
TEXT ·cgocallback(SB),NOSPLIT,$24-24
	NO_LOCAL_POINTERS

	// Skip cgocallbackg, just dropm when fn is nil, and frame is the saved g.
	// It is used to dropm while thread is exiting.

		u.finishInternal()
		return
	}

	// Compute function info flags.
	flag := f.flag
	if f.funcID == abi.FuncID_cgocallback {
		// cgocallback does write SP to switch from the g0 to the curg stack,
		// but it carefully arranges that during the transition BOTH stacks
		// have cgocallback frame valid for unwinding through.
		// So we don't need to exclude it with the other SP-writing functions.
		flag &^= abi.FuncFlagSPWrite
	}

}

// sched.lock must be held.
func checkmcount() {
	assertLockHeld(&sched.lock)

	// Exclude extra M's, which are used for cgocallback from threads
	// created in C.
	//
	// The purpose of the SetMaxThreads limit is to avoid accidental fork
	// bomb from something like millions of goroutines blocking on system