func step(p *[]byte, pc *uint64, val *int32, first bool, arch *sys.Arch) bool {
	uvdelta := readvarint(p)
	if uvdelta == 0 && !first {
		return false
	}
	if uvdelta&1 != 0 {
		uvdelta = ^(uvdelta >> 1)
	} else {
		uvdelta >>= 1
	}
	vdelta := int32(uvdelta)
	pcdelta := readvarint(p) * uint32(arch.MinLC)
	*pc += uint64(pcdelta)
	*val += vdelta
	return true
}

issue:
  - 47949
releaseNotes:
  - |
    **Enabled** [Delta xDS](https://www.envoyproxy.io/docs/envoy/latest/api-docs/xds_protocol#incremental-xds) by default. See upgrade notes for more information.
upgradeNotes:
  - title: Delta xDS on by default
    content: |
      In previous versions, Istio used the "State of the world" xDS protocol to configure Envoy.

    double x1 = 1.2;
    double y1 = 3.4;
    double xDelta = 5.6;
    double yDelta = 7.8;
    LinearTransformation transformation =
        LinearTransformation.mapping(x1, y1).and(x1 + xDelta, y1 + yDelta);
    assertDiagonalLinearTransformation(transformation, x1, y1, xDelta, yDelta);
  }

  public void testMappingAnd_horizontal() {
    double x1 = 1.2;
    double xDelta = 3.4;
    double y = 5.6;

    double x1 = 1.2;
    double y1 = 3.4;
    double xDelta = 5.6;
    double yDelta = 7.8;
    LinearTransformation transformation =
        LinearTransformation.mapping(x1, y1).and(x1 + xDelta, y1 + yDelta);
    assertDiagonalLinearTransformation(transformation, x1, y1, xDelta, yDelta);
  }

  public void testMappingAnd_horizontal() {
    double x1 = 1.2;
    double xDelta = 3.4;
    double y = 5.6;

  }

  /** Returns a new bias. */
  private fun adapt(
    delta: Int,
    numpoints: Int,
    first: Boolean,
  ): Int {
    var delta =
      when {
        first -> delta / DAMP
        else -> delta / 2
      }
    delta += (delta / numpoints)
    var k = 0
    while (delta > ((BASE - TMIN) * TMAX) / 2) {
      delta /= (BASE - TMIN)
      k += BASE
    }

                        break;
                      case 5:
                        map.getAndAdd(key, delta);
                        threadSum += delta;
                        break;
                      case 6:
                        long oldValue = map.put(key, delta);
                        threadSum += delta - oldValue;
                        break;
                      case 7:

func f(x *big, start int64) {
	if delta := inuse() - start; delta < 9<<20 {
		println("after alloc: expected delta at least 9MB, got: ", delta)
	}
	runtime.KeepAlive(x)
	x = nil
	if delta := inuse() - start; delta > 1<<20 {
		println("after drop: expected delta below 1MB, got: ", delta)
	}
	x = new(big)
	if delta := inuse() - start; delta < 9<<20 {
		println("second alloc: expected delta at least 9MB, got: ", delta)
	}

                        break;
                      case 5:
                        map.getAndAdd(key, delta);
                        threadSum += delta;
                        break;
                      case 6:
                        long oldValue = map.put(key, delta);
                        threadSum += delta - oldValue;
                        break;
                      case 7:

//go:nosplit
//go:noinline
func Xadd(ptr *uint32, delta int32) uint32 {
	new := *ptr + uint32(delta)
	*ptr = new
	return new
}

//go:nosplit
//go:noinline
func Xadd64(ptr *uint64, delta int64) uint64 {
	new := *ptr + uint64(delta)
	*ptr = new
	return new
}

//go:nosplit
//go:noinline
func Xadduintptr(ptr *uintptr, delta uintptr) uintptr {
	new := *ptr + delta
	*ptr = new
	return new
}

	"istio.io/istio/pkg/util/sets"
)

var knownOptimizationGaps = sets.New(
	"BlackHoleCluster",
	"InboundPassthroughCluster",
	"PassthroughCluster",
)

// compareDiff compares a Delta and SotW XDS response. This allows checking that the Delta XDS
// response returned the optimal result. Checks include correctness checks (e.g. if a config changed,
// we must include it) and possible optimizations (e.g. we sent a config, but it was not changed).