}
}

func TestDrawOverlap(t *testing.T) {
	for _, op := range []Op{Over, Src} {
		for yoff := -2; yoff <= 2; yoff++ {
		loop:
			for xoff := -2; xoff <= 2; xoff++ {
				m := gradYellow(127).(*image.RGBA)
				dst := m.SubImage(image.Rect(5, 5, 10, 10)).(*image.RGBA)
				src := m.SubImage(image.Rect(5+xoff, 5+yoff, 10+xoff, 10+yoff)).(*image.RGBA)
				b := dst.Bounds()

		ycbcr, _ := m.(*image.YCbCr)
		for y := bounds.Min.Y; y < bounds.Max.Y; y += 16 {
			for x := bounds.Min.X; x < bounds.Max.X; x += 16 {
				for i := 0; i < 4; i++ {
					xOff := (i & 1) * 8
					yOff := (i & 2) * 4
					p := image.Pt(x+xOff, y+yOff)
					if rgba != nil {
						rgbaToYCbCr(rgba, p, &b, &cb[i], &cr[i])
					} else if ycbcr != nil {
						yCbCrToYCbCr(ycbcr, p, &b, &cb[i], &cr[i])
					} else {

      encodings[ 0x10] = encoding // Data Link Escape
      encodings[ 0x11] = encoding // Device Control 1 (oft. XON)
      encodings[ 0x12] = encoding // Device Control 2
      encodings[ 0x13] = encoding // Device Control 3 (oft. XOFF)
      encodings[ 0x14] = encoding // Device Control 4
      encodings[ 0x15] = encoding // Negative Acknowledgment
      encodings[ 0x16] = encoding // Synchronous idle

	"sync"

	"cmd/internal/objabi"
	"cmd/link/internal/loader"
	"cmd/link/internal/sym"
)

// This file handles all algorithms related to XCOFF files generation.
// Most of them are adaptations of the ones in  cmd/link/internal/pe.go
// as PE and XCOFF are based on COFF files.
// XCOFF files generated are 64 bits.

const (
	// Total amount of space to reserve at the start of the file

	tur.err = nil
	doff := off - tur.tu.off
	if doff < 0 || doff >= Offset(len(tur.tu.data)) {
		tur.err = fmt.Errorf("%s: offset %d out of range; max %d", tur.tu.name, doff, len(tur.tu.data))
		return
	}
	tur.b = makeBuf(tur.d, tur.tu, tur.tu.name, off, tur.tu.data[doff:])
}

// AddressSize returns the size in bytes of addresses in the current type unit.
func (tur *typeUnitReader) AddressSize() int {

}

// like staticassign but we are copying an already
// initialized value r.
func (s *Schedule) staticcopy(l *ir.Name, loff int64, rn *ir.Name, typ *types.Type) bool {
	if rn.Class == ir.PFUNC {
		// TODO if roff != 0 { panic }
		staticdata.InitAddr(l, loff, staticdata.FuncLinksym(rn))
		return true
	}
	if rn.Class != ir.PEXTERN || rn.Sym().Pkg != types.LocalPkg {
		return false
	}

		cgoCheckBits(src, typ.GCData, off, size)
		return
	}

	// The type has a GC program. Try to find GC bits somewhere else.
	for _, datap := range activeModules() {
		if cgoInRange(src, datap.data, datap.edata) {
			doff := uintptr(src) - datap.data
			cgoCheckBits(add(src, -doff), datap.gcdatamask.bytedata, off+doff, size)
			return
		}
		if cgoInRange(src, datap.bss, datap.ebss) {
			boff := uintptr(src) - datap.bss

	Fflags   uint16 // Flags
	Fnsyms   uint32 // Number of entries in symbol table
}

const (
	FILHSZ_32 = 20
	FILHSZ_64 = 24
)
const (
	U802TOCMAGIC = 0737 // AIX 32-bit XCOFF
	U64_TOCMAGIC = 0767 // AIX 64-bit XCOFF
)

// Flags that describe the type of the object file.
const (
	F_RELFLG    = 0x0001
	F_EXEC      = 0x0002
	F_LNNO      = 0x0004
	F_FDPR_PROF = 0x0010
	F_FDPR_OPTI = 0x0020

//sys	Seek(fd int, offset int64, whence int) (off int64, err error) = SYS_LSEEK
//sys	Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error)
//sys	sendfile(outfd int, infd int, offset *int64, count int) (written int, err error)
//sys	setfsgid(gid int) (prev int, err error)
//sys	setfsuid(uid int) (prev int, err error)
//sys	Shutdown(fd int, how int) (err error)

	cmsg.Len = uint64(length)
}

//sys	syncFileRange2(fd int, flags int, off int64, n int64) (err error) = SYS_SYNC_FILE_RANGE2

func SyncFileRange(fd int, off int64, n int64, flags int) error {
	// The sync_file_range and sync_file_range2 syscalls differ only in the
	// order of their arguments.
	return syncFileRange2(fd, flags, off, n)