}
	_ = b[i/64]
	j := i + n - 1
	if i/64 == j/64 {
		return uint(sys.OnesCount64((b[i/64] >> (i % 64)) & ((1 << n) - 1)))
	}
	_ = b[j/64]
	s += uint(sys.OnesCount64(b[i/64] >> (i % 64)))
	for k := i/64 + 1; k < j/64; k++ {
		s += uint(sys.OnesCount64(b[k]))
	}
	s += uint(sys.OnesCount64(b[j/64] & ((1 << (j%64 + 1)) - 1)))
	return
}

	for _, tt := range []struct {
		x    uint64
		want int
	}{
		{0b00001111, 4},
		{0b00001110, 3},
		{0b00001100, 2},
		{0b00000000, 0},
	} {
		if got := bits.OnesCount64(tt.x); got != tt.want {
			t.Errorf("OnesCount64(%#x) = %d, want %d", tt.x, got, tt.want)
		}
		if got := bits.OnesCount32(uint32(tt.x)); got != tt.want {
			t.Errorf("OnesCount32(%#x) = %d, want %d", tt.x, got, tt.want)
		}
	}
}

func OnesCount32(x uint32) int {
	return int(pop8tab[x>>24] + pop8tab[x>>16&0xff] + pop8tab[x>>8&0xff] + pop8tab[x&0xff])
}

// OnesCount64 returns the number of one bits ("population count") in x.
func OnesCount64(x uint64) int {
	// Implementation: Parallel summing of adjacent bits.
	// See "Hacker's Delight", Chap. 5: Counting Bits.
	// The following pattern shows the general approach:
	//

	// ppc64x:"POPCNTD"
	// wasm:"I64Popcnt"
	return bits.OnesCount(n)
}

func OnesCount64(n uint64) int {
	// amd64/v2:-".*x86HasPOPCNT" amd64/v3:-".*x86HasPOPCNT"
	// amd64:"POPCNTQ"
	// arm64:"VCNT","VUADDLV"
	// s390x:"POPCNT"
	// ppc64x:"POPCNTD"
	// wasm:"I64Popcnt"
	return bits.OnesCount64(n)
}

func OnesCount32(n uint32) int {
	// amd64/v2:-".*x86HasPOPCNT" amd64/v3:-".*x86HasPOPCNT"

	s := a.name
	if s == "generic" {
		s = ""
	}
	return s
}

// countRegs returns the number of set bits in the register mask.
func countRegs(r regMask) int {
	return bits.OnesCount64(uint64(r))
}

// for sorting a pair of integers by key
type intPair struct {
	key, val int
}
type byKey []intPair

func (a byKey) Len() int           { return len(a) }

		// This is a serious bug - an object is live (due to the KeepAlive
		// call below), but isn't reported as such.
		t.Fatalf("live object not in reachable set; want %b, got %b", want, got)
	}
	if bits.OnesCount64(got&^want) > 1 {
		// Note: we can occasionally have a value that is retained even though
		// it isn't live, due to conservative scanning of stack frames.
		// See issue 67204. For now, we allow a "slop" of 1 unintentionally

			if chunk == nil {
				continue
			}
			pg := chunk.scavenged.popcntRange(0, pallocChunkPages)
			slow.HeapReleased += uint64(pg) * pageSize
		}
		for _, p := range allp {
			pg := sys.OnesCount64(p.pcache.scav)
			slow.HeapReleased += uint64(pg) * pageSize
		}

		getg().m.mallocing--
	})

	startTheWorld(stw)
	return
}