create procedure sys.sp_MSBitmapXOr
    @bm1 varbinary(128),
    @bm2 varbinary(128),
    @bmout varbinary(128) output
as
    declare @len1 int
    set @len1= datalength(@bm1)
    declare @len2 int
    set @len2= datalength(@bm2)

    declare @idx int
    set @idx= 1

    while @idx <= @len2
    begin
        if 1=@idx
        begin
            set @bmout= cast(substring(@bm1, @idx, 1) as tinyint)  cast(substring(@bm2, @idx, 1) as tinyint)
            if @@error<>0 return 1
        end
        else
        begin
            set @bmout= @bmout + cast(cast(substring(@bm1, @idx, 1) as tinyint)  cast(substring(@bm2, @idx, 1) as tinyint) as varbinary)
            if @@error<>0 return 1
        end

        set @idx= @idx+1
    end

    if @len1 > @len2
    begin
        set @bmout= @bmout + substring(@bm1, @idx, @len1-@len2)
        if @@error<>0 return 1
    end

    return 0