Zig 0.17.0-dev (Split by item)

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ctzXi2

count0bits.ctzXi2

inline fn ctzXi2(comptime T: type, a: T) i32

File

lib/compiler_rt/count0bits.zig:165

Code

inline fn ctzXi2(comptime T: type, a: T) i32 {
    var x = switch (@bitSizeOf(T)) {
        32 => @as(u32, @bitCast(a)),
        64 => @as(u64, @bitCast(a)),
        128 => @as(u128, @bitCast(a)),
        else => unreachable,
    };
    var n: T = 1;
    // Number of trailing zeroes as binary search, from Hacker's Delight
    var mask: @TypeOf(x) = std.math.maxInt(@TypeOf(x));
    comptime var shift = @bitSizeOf(T);
    if (x == 0) return shift;
    inline while (shift > 1) {
        shift = shift >> 1;
        mask = mask >> shift;
        if ((x & mask) == 0) {
            n = n + shift;
            x = x >> shift;
        }
    }
    return @intCast(n - @as(T, @bitCast((x & 1))));
}