function Delta(Arg : signed; Cnt : natural) return signed is
variable tmp : signed(Arg'range);
constant lo : integer := Arg'high -cnt +1;
begin
for n in Arg'high downto lo loop
tmp(n) := Arg(Arg'high);
end loop;
for n in Arg'high -cnt downto 0 loop
tmp(n) := Arg(n +cnt);
end loop;
return tmp;
end function Delta;
哪位大哥帮我解读下这段程序,什么意思?