* interpreted as an unsigned 64-bit value. Specifically, the sign bit of {@code bits} is
   * interpreted as a normal bit, and all other bits are treated as usual.
   *
   * <p>If the argument is nonnegative, the returned result will be equal to {@code bits},
   * otherwise, the result will be equal to {@code 2^64 + bits}.
   *
   * <p>To represent decimal constants less than {@code 2^63}, consider {@link #valueOf(long)}

   * interpreted as an unsigned 64-bit value. Specifically, the sign bit of {@code bits} is
   * interpreted as a normal bit, and all other bits are treated as usual.
   *
   * <p>If the argument is nonnegative, the returned result will be equal to {@code bits},
   * otherwise, the result will be equal to {@code 2^64 + bits}.
   *
   * <p>To represent decimal constants less than {@code 2^63}, consider {@link #valueOf(long)}

)

func (n *miniNode) Typecheck() uint8 { return n.bits.get2(miniTypecheckShift) }
func (n *miniNode) SetTypecheck(x uint8) {
	if x > 2 {
		panic(fmt.Sprintf("cannot SetTypecheck %d", x))
	}
	n.bits.set2(miniTypecheckShift, x)
}

func (n *miniNode) Walked() bool     { return n.bits&miniWalked != 0 }
func (n *miniNode) SetWalked(x bool) { n.bits.set(miniWalked, x) }

// Empty, immutable graph structure.

package test

import (
	"math/bits"
	"testing"
)

func TestBitLen64(t *testing.T) {
	for i := 0; i <= 64; i++ {
		got := bits.Len64(1 << i)
		want := i + 1
		if want == 65 {
			want = 0
		}
		if got != want {
			t.Errorf("Len64(1<<%d) = %d, want %d", i, got, want)
		}
	}
}

func TestBitLen32(t *testing.T) {
	for i := 0; i <= 32; i++ {
		got := bits.Len32(1 << i)
		want := i + 1

  // The mask for the sign bit.
  static const Bits kSignBitMask = static_cast<Bits>(1) << (kBitCount - 1);

  // The mask for the fraction bits.
  static const Bits kFractionBitMask =
    ~static_cast<Bits>(0) >> (kExponentBitCount + 1);

  // The mask for the exponent bits.
  static const Bits kExponentBitMask = ~(kSignBitMask | kFractionBitMask);

  // How many ULP's (Units in the Last Place) we want to tolerate when

package runtime

import (
	"internal/goarch"
	"internal/goos"
	"unsafe"
)

const (
	// addrBits is the number of bits needed to represent a virtual address.
	//
	// See heapAddrBits for a table of address space sizes on
	// various architectures. 48 bits is enough for all
	// architectures except s390x.
	//
	// On AMD64, virtual addresses are 48-bit (or 57-bit) numbers sign extended to 64.

		x = -x
		sign = true
	}

	// rough cbrt to 5 bits
	t := Float64frombits(Float64bits(x)/3 + B1<<32)
	if x < SmallestNormal {
		// subnormal number
		t = float64(1 << 54) // set t= 2**54
		t *= x
		t = Float64frombits(Float64bits(t)/3 + B2<<32)
	}

	// new cbrt to 23 bits
	r := t * t / x
	s := C + r*t
	t *= G + F/(s+E+D/s)

	// chop to 22 bits, make larger than cbrt(x)

  // The mask for the sign bit.
  static const Bits kSignBitMask = static_cast<Bits>(1) << (kBitCount - 1);

  // The mask for the fraction bits.
  static const Bits kFractionBitMask =
    ~static_cast<Bits>(0) >> (kExponentBitCount + 1);

  // The mask for the exponent bits.
  static const Bits kExponentBitMask = ~(kSignBitMask | kFractionBitMask);

  // How many ULP's (Units in the Last Place) we want to tolerate when

	if ps == zs {
		// Adding (pm1:pm2) + (zm1:zm2)
		pm2, c = bits.Add64(pm2, zm2, 0)
		pm1, _ = bits.Add64(pm1, zm1, c)
		pe -= int32(^pm1 >> 63)
		pm1, m = shrcompress(pm1, pm2, uint(64+pm1>>63))
	} else {
		// Subtracting (pm1:pm2) - (zm1:zm2)
		// TODO: should we special-case cancellation?
		pm2, c = bits.Sub64(pm2, zm2, 0)
		pm1, _ = bits.Sub64(pm1, zm1, c)
		nz := lz(pm1, pm2)
		pe -= nz

		{8e-45, 0x00000006},
		{9e-45, 0x00000006},
		{1.0e-44, 0x00000007},
		{1.1e-44, 0x00000008},
		{1.2e-44, 0x00000009},
	} {
		got := math.Float32bits(t.value)
		want := t.bits
		if got != want {
			panic(fmt.Sprintf("bits(%g) = 0x%08x; want 0x%08x", t.value, got, want))
		}
	}