func stdcall2(fn stdFunction, a0, a1 uintptr) uintptr {
	mp := getg().m
	mp.libcall.n = 2
	mp.libcall.args = uintptr(noescape(unsafe.Pointer(&a0)))
	return stdcall(fn)
}

//go:nosplit
//go:cgo_unsafe_args
func stdcall3(fn stdFunction, a0, a1, a2 uintptr) uintptr {
	mp := getg().m
	mp.libcall.n = 3
	mp.libcall.args = uintptr(noescape(unsafe.Pointer(&a0)))
	return stdcall(fn)
}

//go:nosplit

// which prevents us from allocating more stack.
//
//go:nosplit
func sysAllocOS(n uintptr) unsafe.Pointer {
	return unsafe.Pointer(stdcall4(_VirtualAlloc, 0, n, _MEM_COMMIT|_MEM_RESERVE, _PAGE_READWRITE))
}

func sysUnusedOS(v unsafe.Pointer, n uintptr) {
	r := stdcall3(_VirtualFree, uintptr(v), n, _MEM_DECOMMIT)
	if r != 0 {
		return
	}

	// Decommit failed. Usual reason is that we've merged memory from two different

	var werflags uintptr
	stdcall2(_WerGetFlags, currentProcess, uintptr(unsafe.Pointer(&werflags)))
	stdcall1(_WerSetFlags, werflags|_WER_FAULT_REPORTING_NO_UI)
}

// enableWER re-enables Windows error reporting without fault reporting UI.
func enableWER() {
	// re-enable Windows Error Reporting
	errormode := stdcall0(_GetErrorMode)
	if errormode&_SEM_NOGPFAULTERRORBOX != 0 {
		stdcall1(_SetErrorMode, errormode^_SEM_NOGPFAULTERRORBOX)

	errno := stdcall2(_NtCancelWaitCompletionPacket, mp.waitIocpHandle, 1)
	switch errno {
	case STATUS_CANCELLED:
		// STATUS_CANCELLED is returned when the associated timer has already expired,
		// in which automatically cancels the wait completion packet.
		fallthrough
	case STATUS_SUCCESS:
		dt := -delay / 100 // relative sleep (negative), 100ns units

import "unsafe"

const MaxArgs = maxArgs

var (
	OsYield                 = osyield
	TimeBeginPeriodRetValue = &timeBeginPeriodRetValue
)

func NumberOfProcessors() int32 {
	var info systeminfo
	stdcall1(_GetSystemInfo, uintptr(unsafe.Pointer(&info)))
	return int32(info.dwnumberofprocessors)
}

type ContextStub struct {
	context
}

func (c ContextStub) GetPC() uintptr {
	return c.ip()
}

}

type callbackArgs struct {
	index uintptr
	// args points to the argument block.
	//
	// For cdecl and stdcall, all arguments are on the stack.
	//
	// For fastcall, the trampoline spills register arguments to
	// the reserved spill slots below the stack arguments,
	// resulting in a layout equivalent to stdcall.
	//
	// For arm, the trampoline stores the register arguments just

	val, err = syscall2(&libc_dup2, old, new)
	return
}

//go:linkname syscall_execve syscall.execve
//go:nosplit
func syscall_execve(path, argv, envp uintptr) (err uintptr) {
	_, err = syscall3(&libc_execve, path, argv, envp)
	return
}

// like exit, but must not split stack, for fork.
//
//go:linkname syscall_exit syscall.exit
//go:nosplit
func syscall_exit(code uintptr) {

	// newosproc0.
	if gp != nil {
		r, errno := syscall3(&libc_write, uintptr(fd), uintptr(p), uintptr(n))
		if int32(r) < 0 {
			return -int32(errno)
		}
		return int32(r)
	}
	// Note that in this case we can't return a valid errno value.
	return write2(fd, uintptr(p), n)
}

//go:nosplit
func read(fd int32, p unsafe.Pointer, n int32) int32 {
	r, errno := syscall3(&libc_read, uintptr(fd), uintptr(p), uintptr(n))

	CMPL	CX, $0
	JE	docall

	// Copy args to the stack.
	MOVL	CX, AX
	SALL	$2, AX
	SUBL	AX, SP			// room for args
	MOVL	SP, DI
	MOVL	libcall_args(BX), SI
	CLD
	REP; MOVSL

docall:
	// Call stdcall or cdecl function.
	// DI SI BP BX are preserved, SP is not
	CALL	libcall_fn(BX)
	MOVL	BP, SP

	// Return result.
	MOVL	fn+0(FP), BX
	MOVL	AX, libcall_r1(BX)
	MOVL	DX, libcall_r2(BX)

	// GetLastError().

			dll := syscall.MustLoadDLL(dllPath)
			defer dll.Release()
			for _, cbf := range getCallbackTestFuncs() {
				t.Run(cbf.cName(false), func(t *testing.T) {
					stdcall := syscall.NewCallback(cbf.goFunc)
					cbf.testOne(t, dll, false, stdcall)
				})
				t.Run(cbf.cName(true), func(t *testing.T) {
					cdecl := syscall.NewCallbackCDecl(cbf.goFunc)
					cbf.testOne(t, dll, true, cdecl)
				})
			}
		})
	}