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microwatt/decode2.vhdl

300 lines
8.4 KiB
VHDL

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
library work;
use work.decode_types.all;
use work.common.all;
use work.helpers.all;
use work.insn_helpers.all;
entity decode2 is
port (
clk : in std_ulogic;
d_in : in Decode1ToDecode2Type;
e_out : out Decode2ToExecute1Type;
m_out : out Decode2ToMultiplyType;
l_out : out Decode2ToLoadstore1Type;
r_in : in RegisterFileToDecode2Type;
r_out : out Decode2ToRegisterFileType;
c_in : in CrFileToDecode2Type;
c_out : out Decode2ToCrFileType
);
end entity decode2;
architecture behaviour of decode2 is
signal d : Decode1ToDecode2Type;
type decode_input_reg_t is record
reg_valid : std_ulogic;
reg : std_ulogic_vector(4 downto 0);
data : std_ulogic_vector(63 downto 0);
end record;
function decode_input_reg_a (t : input_reg_a_t; insn_in : std_ulogic_vector(31 downto 0);
reg_data : std_ulogic_vector(63 downto 0)) return decode_input_reg_t is
begin
case t is
when RA =>
return ('1', insn_ra(insn_in), reg_data);
when RA_OR_ZERO =>
return ('1', insn_ra(insn_in), ra_or_zero(reg_data, insn_ra(insn_in)));
when RS =>
return ('1', insn_rs(insn_in), reg_data);
when NONE =>
return ('0', (others => '0'), (others => '0'));
end case;
end;
function decode_input_reg_b (t : input_reg_b_t; insn_in : std_ulogic_vector(31 downto 0);
reg_data : std_ulogic_vector(63 downto 0)) return decode_input_reg_t is
begin
case t is
when RB =>
return ('1', insn_rb(insn_in), reg_data);
when RS =>
return ('1', insn_rs(insn_in), reg_data);
when CONST_UI =>
return ('0', (others => '0'), std_ulogic_vector(resize(unsigned(insn_ui(insn_in)), 64)));
when CONST_SI =>
return ('0', (others => '0'), std_ulogic_vector(resize(signed(insn_si(insn_in)), 64)));
when CONST_SI_HI =>
return ('0', (others => '0'), std_ulogic_vector(resize(signed(insn_si(insn_in)) & x"0000", 64)));
when CONST_UI_HI =>
return ('0', (others => '0'), std_ulogic_vector(resize(unsigned(insn_si(insn_in)) & x"0000", 64)));
when CONST_LI =>
return ('0', (others => '0'), std_ulogic_vector(resize(signed(insn_li(insn_in)) & "00", 64)));
when CONST_BD =>
return ('0', (others => '0'), std_ulogic_vector(resize(signed(insn_bd(insn_in)) & "00", 64)));
when CONST_DS =>
return ('0', (others => '0'), std_ulogic_vector(resize(signed(insn_ds(insn_in)) & "00", 64)));
when NONE =>
return ('0', (others => '0'), (others => '0'));
end case;
end;
function decode_input_reg_c (t : input_reg_c_t; insn_in : std_ulogic_vector(31 downto 0);
reg_data : std_ulogic_vector(63 downto 0)) return decode_input_reg_t is
begin
case t is
when RS =>
return ('1', insn_rs(insn_in), reg_data);
when NONE =>
return ('0', (others => '0'), (others => '0'));
end case;
end;
function decode_output_reg (t : output_reg_a_t; insn_in : std_ulogic_vector(31 downto 0)) return std_ulogic_vector is
begin
case t is
when RT =>
return insn_rt(insn_in);
when RA =>
return insn_ra(insn_in);
when NONE =>
return "00000";
end case;
end;
function decode_const_a (t : constant_a_t; insn_in : std_ulogic_vector(31 downto 0)) return std_ulogic_vector is
begin
case t is
when SH =>
return "00" & insn_sh(insn_in);
when SH32 =>
return "000" & insn_sh32(insn_in);
when FXM =>
return insn_fxm(insn_in);
when BO =>
return "000" & insn_bo(insn_in);
when BF =>
return "00000" & insn_bf(insn_in);
when TOO =>
return "000" & insn_to(insn_in);
when BC =>
return "000" & insn_bc(insn_in);
when NONE =>
return "00000000";
end case;
end;
function decode_const_b (t : constant_b_t; insn_in : std_ulogic_vector(31 downto 0)) return std_ulogic_vector is
begin
case t is
when MB =>
return insn_mb(insn_in);
when ME =>
return insn_me(insn_in);
when MB32 =>
return "0" & insn_mb32(insn_in);
when BI =>
return "0" & insn_bi(insn_in);
when L =>
return "00000" & insn_l(insn_in);
when NONE =>
return "000000";
end case;
end;
function decode_const_c (t : constant_c_t; insn_in : std_ulogic_vector(31 downto 0)) return std_ulogic_vector is
begin
case t is
when ME32 =>
return insn_me32(insn_in);
when BH =>
return "000" & insn_bh(insn_in);
when NONE =>
return "00000";
end case;
end;
function decode_rc (t : rc_t; insn_in : std_ulogic_vector(31 downto 0)) return std_ulogic is
begin
case t is
when RC =>
return insn_rc(insn_in);
when ONE =>
return '1';
when NONE =>
return '0';
end case;
end;
begin
decode2_0: process(clk)
begin
if rising_edge(clk) then
d <= d_in;
end if;
end process;
r_out.read1_reg <= insn_ra(d.insn) when (d.decode.input_reg_a = RA) else
insn_ra(d.insn) when d.decode.input_reg_a = RA_OR_ZERO else
insn_rs(d.insn) when d.decode.input_reg_a = RS else
(others => '0');
r_out.read2_reg <= insn_rb(d.insn) when d.decode.input_reg_b = RB else
insn_rs(d.insn) when d.decode.input_reg_b = RS else
(others => '0');
r_out.read3_reg <= insn_rs(d.insn) when d.decode.input_reg_c = RS else
(others => '0');
decode2_1: process(all)
variable mul_a : std_ulogic_vector(63 downto 0);
variable mul_b : std_ulogic_vector(63 downto 0);
variable decoded_reg_a : decode_input_reg_t;
variable decoded_reg_b : decode_input_reg_t;
variable decoded_reg_c : decode_input_reg_t;
begin
e_out <= Decode2ToExecute1Init;
l_out <= Decode2ToLoadStore1Init;
m_out <= Decode2ToMultiplyInit;
mul_a := (others => '0');
mul_b := (others => '0');
--e_out.input_cr <= d.decode.input_cr;
--m_out.input_cr <= d.decode.input_cr;
--e_out.output_cr <= d.decode.output_cr;
decoded_reg_a := decode_input_reg_a (d.decode.input_reg_a, d.insn, r_in.read1_data);
decoded_reg_b := decode_input_reg_b (d.decode.input_reg_b, d.insn, r_in.read2_data);
decoded_reg_c := decode_input_reg_c (d.decode.input_reg_c, d.insn, r_in.read3_data);
case d.decode.unit is
when ALU =>
e_out.valid <= d.valid;
when LDST =>
l_out.valid <= d.valid;
when MUL =>
m_out.valid <= d.valid;
when NONE =>
e_out.valid <= d.valid;
e_out.insn_type <= OP_ILLEGAL;
end case;
-- execute unit
e_out.nia <= d.nia;
e_out.insn_type <= d.decode.insn_type;
e_out.read_reg1 <= decoded_reg_a.reg;
e_out.read_data1 <= decoded_reg_a.data;
e_out.read_reg2 <= decoded_reg_b.reg;
e_out.read_data2 <= decoded_reg_b.data;
e_out.write_reg <= decode_output_reg(d.decode.output_reg_a, d.insn);
e_out.rc <= decode_rc(d.decode.rc, d.insn);
e_out.cr <= c_in.read_cr_data;
e_out.input_carry <= d.decode.input_carry;
e_out.output_carry <= d.decode.output_carry;
if d.decode.lr then
e_out.lr <= insn_lk(d.insn);
end if;
e_out.const1 <= decode_const_a(d.decode.const_a, d.insn);
e_out.const2 <= decode_const_b(d.decode.const_b, d.insn);
e_out.const3 <= decode_const_c(d.decode.const_c, d.insn);
-- multiply unit
m_out.nia <= d.nia;
m_out.insn_type <= d.decode.insn_type;
mul_a := decoded_reg_a.data;
mul_b := decoded_reg_b.data;
m_out.write_reg <= decode_output_reg(d.decode.output_reg_a, d.insn);
m_out.rc <= decode_rc(d.decode.rc, d.insn);
if d.decode.mul_32bit = '1' then
if d.decode.mul_signed = '1' then
m_out.data1 <= (others => mul_a(31));
m_out.data1(31 downto 0) <= mul_a(31 downto 0);
m_out.data2 <= (others => mul_b(31));
m_out.data2(31 downto 0) <= mul_b(31 downto 0);
else
m_out.data1 <= '0' & x"00000000" & mul_a(31 downto 0);
m_out.data2 <= '0' & x"00000000" & mul_b(31 downto 0);
end if;
else
if d.decode.mul_signed = '1' then
m_out.data1 <= mul_a(63) & mul_a;
m_out.data2 <= mul_b(63) & mul_b;
else
m_out.data1 <= '0' & mul_a;
m_out.data2 <= '0' & mul_b;
end if;
end if;
-- load/store unit
l_out.nia <= d.nia;
l_out.update_reg <= decoded_reg_a.reg;
l_out.addr1 <= decoded_reg_a.data;
l_out.addr2 <= decoded_reg_b.data;
l_out.data <= decoded_reg_c.data;
l_out.write_reg <= decode_output_reg(d.decode.output_reg_a, d.insn);
if d.decode.insn_type = OP_LOAD then
l_out.load <= '1';
else
l_out.load <= '0';
end if;
case d.decode.length is
when is1B =>
l_out.length <= "0001";
when is2B =>
l_out.length <= "0010";
when is4B =>
l_out.length <= "0100";
when is8B =>
l_out.length <= "1000";
when NONE =>
l_out.length <= "0000";
end case;
l_out.byte_reverse <= d.decode.byte_reverse;
l_out.sign_extend <= d.decode.sign_extend;
l_out.update <= d.decode.update;
end process;
end architecture behaviour;