library ieee;
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library ieee;
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use ieee.std_logic_1164.all;
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use ieee.std_logic_1164.all;
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use ieee.std_logic_arith.all;
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use ieee.std_logic_arith.all;
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package ahb_funct is
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package ahb_funct is
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function nb_bits (A : std_logic_vector) return NATURAL;
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function nb_bits (A : std_logic_vector) return NATURAL;
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function nb_bits (A : INTEGER) return NATURAL;
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function nb_bits (A : INTEGER) return NATURAL;
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procedure fixed_priority(
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procedure fixed_priority(
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t_turn: out integer;
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t_turn: out integer;
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t_grant: out integer;
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t_grant: out integer;
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req: in std_logic_vector;
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req: in std_logic_vector;
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turn: in integer);
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turn: in integer);
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procedure round_robin(
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procedure round_robin(
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def_elem: in integer;
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def_elem: in integer;
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t_turn: out integer;
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t_turn: out integer;
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t_grant: out integer;
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t_grant: out integer;
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req: in std_logic_vector;
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req: in std_logic_vector;
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turn: in integer);
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turn: in integer);
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procedure random_priority(
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procedure random_priority(
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def_elem: in integer;
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def_elem: in integer;
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t_turn: out integer;
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t_turn: out integer;
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t_grant: out integer;
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t_grant: out integer;
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random: in integer;
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random: in integer;
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req: in std_logic_vector;
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req: in std_logic_vector;
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turn: in integer);
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turn: in integer);
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end ahb_funct;
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end ahb_funct;
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package body ahb_funct is
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package body ahb_funct is
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function nb_bits (A : std_logic_vector) return NATURAL is
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function nb_bits (A : std_logic_vector) return NATURAL is
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variable logres : NATURAL ;
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variable logres : NATURAL ;
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begin
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begin
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logres := 1;
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logres := 1;
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for i in A'length-1 downto 0 loop
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for i in A'length-1 downto 0 loop
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if A(i) = '1' then
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if A(i) = '1' then
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logres := i;
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logres := i;
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exit;
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exit;
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end if;
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end if;
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end loop;
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end loop;
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return logres;
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return logres;
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end nb_bits;
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end nb_bits;
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function nb_bits (A : INTEGER) return NATURAL is
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function nb_bits (A : INTEGER) return NATURAL is
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variable logres : NATURAL ;
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variable logres : NATURAL ;
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begin
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begin
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logres := 1;
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logres := 1;
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for i in 0 to 30 loop
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for i in 0 to 30 loop
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if 2**i <= A then
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if 2**i <= A then
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logres := i+1;
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logres := i+1;
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end if;
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end if;
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end loop;
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end loop;
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return logres;
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return logres;
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end nb_bits;
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end nb_bits;
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procedure fixed_priority(
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procedure fixed_priority(
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t_turn: out integer;-- range 0 to num_elem-1;
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t_turn: out integer;-- range 0 to num_elem-1;
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t_grant: out integer;
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t_grant: out integer;
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req: in std_logic_vector;
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req: in std_logic_vector;
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turn: in integer-- range 0 to num_elem-1
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turn: in integer-- range 0 to num_elem-1
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) is
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) is
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begin
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begin
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t_grant := 0;
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t_grant := 0;
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t_turn := 0;
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t_turn := 0;
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req_for:for i in req'length-1 downto 0 loop
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req_for:for i in req'length-1 downto 0 loop
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if req(i) = '1' then
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if req(i) = '1' then
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t_grant := i;
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t_grant := i;
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end if;
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end if;
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end loop;
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end loop;
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end fixed_priority;
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end fixed_priority;
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procedure round_robin(
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procedure round_robin(
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def_elem: in integer;
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def_elem: in integer;
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t_turn: out integer;-- range 0 to num_elem-1;
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t_turn: out integer;-- range 0 to num_elem-1;
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t_grant: out integer;-- range 0 to num_elem-1;
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t_grant: out integer;-- range 0 to num_elem-1;
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req: in std_logic_vector;
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req: in std_logic_vector;
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turn: in integer-- range 0 to num_elem-1
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turn: in integer-- range 0 to num_elem-1
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) is
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) is
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constant req_size: integer:= req'length;
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constant req_size: integer:= req'length;
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variable v_req: std_logic_vector(req_size*2-1 downto 0);
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variable v_req: std_logic_vector(req_size*2-1 downto 0);
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type turn_array is array (req_size-1 downto 0) of std_logic_vector(req_size-1 downto 0);
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type turn_array is array (req_size-1 downto 0) of std_logic_vector(req_size-1 downto 0);
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variable v_turn: turn_array;
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variable v_turn: turn_array;
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begin
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begin
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t_grant := def_elem;
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t_grant := def_elem;
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t_turn := turn;
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t_turn := turn;
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v_req := req&req;--concatenation
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v_req := req&req;--concatenation
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for i in 0 to req_size-1 loop
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for i in 0 to req_size-1 loop
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v_turn(i) := v_req(i+req_size-1 downto i);
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v_turn(i) := v_req(i+req_size-1 downto i);
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end loop;
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end loop;
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for j in 0 to req_size-1 loop
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for j in 0 to req_size-1 loop
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if j=turn then
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if j=turn then
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for jj in 0 to req_size-1 loop
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for jj in 0 to req_size-1 loop
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if v_turn(j)(jj)='1' then
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if v_turn(j)(jj)='1' then
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if turn+jj >=req'length then
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if turn+jj >=req'length then
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t_turn := turn+jj-req_size;
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t_turn := turn+jj-req_size;
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t_grant := turn+jj-req_size;
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t_grant := turn+jj-req_size;
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else
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else
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t_turn := turn+jj;
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t_turn := turn+jj;
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t_grant := turn+jj;
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t_grant := turn+jj;
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end if;
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end if;
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end if;
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end if;
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end loop; -- jj
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end loop; -- jj
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end if;
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end if;
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end loop; -- j
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end loop; -- j
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end round_robin;
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end round_robin;
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procedure random_priority(
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procedure random_priority(
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def_elem: in integer;
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def_elem: in integer;
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t_turn: out integer;-- range 0 to num_elem-1;
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t_turn: out integer;-- range 0 to num_elem-1;
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t_grant: out integer;-- range 0 to num_elem-1;
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t_grant: out integer;-- range 0 to num_elem-1;
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random: in integer;-- range 0 to 2**(nb_bits(num_elem));
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random: in integer;-- range 0 to 2**(nb_bits(num_elem));
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req: in std_logic_vector;
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req: in std_logic_vector;
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turn: in integer-- range 0 to num_elem-1
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turn: in integer-- range 0 to num_elem-1
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) is
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) is
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constant req_size: integer:= req'length;
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constant req_size: integer:= req'length;
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variable j, v_turn, upper_limit: integer;
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variable j, v_turn, upper_limit: integer;
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begin
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begin
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t_grant := def_elem;
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t_grant := def_elem;
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upper_limit := 2**(nb_bits(req_size))-1;
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upper_limit := 2**(nb_bits(req_size))-1;
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v_turn := turn;
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v_turn := turn;
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req_for:for i in upper_limit downto 0 loop
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req_for:for i in upper_limit downto 0 loop
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if ((i >= random) and (i <= random+upper_limit)) then
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if ((i >= random) and (i <= random+upper_limit)) then
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j := i mod req_size;
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j := i mod req_size;
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if req(j) = '1' then
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if req(j) = '1' then
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t_grant := j;
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t_grant := j;
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if turn=req_size-1 then
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if turn=req_size-1 then
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v_turn := 0;
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v_turn := 0;
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else
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else
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v_turn := turn+1;
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v_turn := turn+1;
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end if;
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end if;
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end if;
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end if;
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t_turn := v_turn;
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t_turn := v_turn;
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--synopsys translate_off
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--synopsys translate_off
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assert (v_turn>=0 and v_turn<req_size) report "####ERROR: WRONG ARBITRATION!!!" severity failure;
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assert (v_turn>=0 and v_turn<req_size) report "####ERROR: WRONG ARBITRATION!!!" severity failure;
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--synopsys translate_on
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--synopsys translate_on
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end if;
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end if;
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end loop;
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end loop;
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end random_priority;
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end random_priority;
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end ahb_funct;
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end ahb_funct;
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