return x
	case x < 0:
		return NaN()
	}
	ix := Float64bits(x)
	// normalize x
	exp := int((ix >> shift) & mask)
	if exp == 0 { // subnormal x
		for ix&(1<<shift) == 0 {
			ix <<= 1
			exp--
		}
		exp++
	}
	exp -= bias // unbias exponent
	ix &^= mask << shift
	ix |= 1 << shift
	if exp&1 == 1 { // odd exp, double x to make it even
		ix <<= 1
	}

func (c *pageCache) allocN(npages uintptr) (uintptr, uintptr) {
	i := findBitRange64(c.cache, uint(npages))
	if i >= 64 {
		return 0, 0
	}
	mask := ((uint64(1) << npages) - 1) << i
	scav := sys.OnesCount64(c.scav & mask)
	c.cache &^= mask // mark in-use bits
	c.scav &^= mask  // clear scavenged bits
	return c.base + uintptr(i*pageSize), uintptr(scav) * pageSize
}

// flush empties out unallocated free pages in the given cache

//	10.0.0.1/24 and 10.0.0.0/25 are not the same subnet.
func IPNetEqual(ipnet1, ipnet2 *net.IPNet) bool {
	if ipnet1 == nil || ipnet2 == nil {
		return false
	}
	if reflect.DeepEqual(ipnet1.Mask, ipnet2.Mask) && ipnet1.Contains(ipnet2.IP) && ipnet2.Contains(ipnet1.IP) {
		return true
	}
	return false
}

// Returns if the given err is "connection reset by peer" error.
func IsConnectionReset(err error) bool {

      setPredecessor(succ, pred);
    }
  }

  @Override
  void insertEntry(
      int entryIndex, @ParametricNullness K key, @ParametricNullness V value, int hash, int mask) {
    super.insertEntry(entryIndex, key, value, hash, mask);
    setSucceeds(lastEntry, entryIndex);
    setSucceeds(entryIndex, ENDPOINT);
  }

  @Override
  void accessEntry(int index) {
    if (accessOrder) {

	separator := byte(0x80) // gets reset to 0x00 once used
	for i := byte(0); i < chunk; i++ {
		mask := byte(int8(i-nx) >> 7) // 0x00 after the end of data

		// if we reached the end of the data, replace with 0x80 or 0x00
		d.x[i] = (^mask & separator) | (mask & d.x[i])

		// zero the separator once used
		separator &= mask

		if i >= 56 {
			// we might have to write the length here if all fit in one block

		name string
		cidr string
	}{
		{
			name: "invalid IPv4 loopback CIDR",
			cidr: "192.168.1.1/24",
		},
		{
			name: "invalid CIDR with mask below range",
			cidr: "10.0.0.1/7",
		},
		{
			name: "invalid CIDR with mask above range",
			cidr: "172.16.0.1/40",
		},
	}

	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			err := ValidateIPv4LoopbackCidr(tc.cidr)

	// for VPERMXOR
	MOVD $consts<>+0xa0(SB), MASK
	MOVD $16, R20
	// V16
	LXVW4X (CONSTBASE)(R0), VS48
	ADD $80,CONSTBASE

	// Load key into V17,V18
	LXVW4X (KEY)(R0), VS49
	LXVW4X (KEY)(R8), VS50

	// Load CNT, NONCE into V19
	LXVW4X (CNT)(R0), VS51

	// Clear V27
	VXOR V27, V27, V27

	// V28
	LXVW4X (CONSTBASE)(R11), VS60

	// Load mask constants for VPERMXOR
	LXVW4X (MASK)(R0), V20

		// it was deliver in a non-Go thread.
		c.set_sigcode(_SI_USER)
	}
}

//go:nosplit
//go:nowritebarrierrec
func sigaddset(mask *sigset, i int) {
	(*mask)[(i-1)/64] |= 1 << ((uint32(i) - 1) & 63)
}

func sigdelset(mask *sigset, i int) {
	(*mask)[(i-1)/64] &^= 1 << ((uint32(i) - 1) & 63)
}

func setProcessCPUProfiler(hz int32) {
	setProcessCPUProfilerTimer(hz)
}

	ADDQ	$16, DI
	SUBQ	$16, R8
	JMP	loop

diff64:
	ADDQ	$48, SI
	ADDQ	$48, DI
	JMP	diff16
diff48:
	ADDQ	$32, SI
	ADDQ	$32, DI
	JMP	diff16
diff32:
	ADDQ	$16, SI
	ADDQ	$16, DI
	// AX = bit mask of differences
diff16:
	BSFQ	AX, BX	// index of first byte that differs
	XORQ	AX, AX
	MOVB	(SI)(BX*1), CX
	CMPB	CX, (DI)(BX*1)
	SETHI	AX
	LEAQ	-1(AX*2), AX	// convert 1/0 to +1/-1
	RET

		return 1 << nValueSpec
	}
	return 0
}

func maskOf(nodes []ast.Node) uint64 {
	if nodes == nil {
		return math.MaxUint64 // match all node types
	}
	var mask uint64
	for _, n := range nodes {
		mask |= typeOf(n)
	}
	return mask