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385 lines
14 KiB
VHDL
385 lines
14 KiB
VHDL
library ieee;
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use ieee.std_logic_1164.all;
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use ieee.numeric_std.all;
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library work;
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use work.decode_types.all;
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use work.common.all;
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use work.helpers.all;
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use work.insn_helpers.all;
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entity decode2 is
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generic (
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EX1_BYPASS : boolean := true
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);
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port (
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clk : in std_ulogic;
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rst : in std_ulogic;
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complete_in : in std_ulogic;
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stall_in : in std_ulogic;
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stall_out : out std_ulogic;
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stopped_out : out std_ulogic;
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flush_in: in std_ulogic;
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d_in : in Decode1ToDecode2Type;
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e_out : out Decode2ToExecute1Type;
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r_in : in RegisterFileToDecode2Type;
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r_out : out Decode2ToRegisterFileType;
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c_in : in CrFileToDecode2Type;
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c_out : out Decode2ToCrFileType
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);
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end entity decode2;
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architecture behaviour of decode2 is
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type reg_type is record
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e : Decode2ToExecute1Type;
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end record;
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signal r, rin : reg_type;
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type decode_input_reg_t is record
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reg_valid : std_ulogic;
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reg : gspr_index_t;
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data : std_ulogic_vector(63 downto 0);
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end record;
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type decode_output_reg_t is record
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reg_valid : std_ulogic;
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reg : gspr_index_t;
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end record;
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function decode_input_reg_a (t : input_reg_a_t; insn_in : std_ulogic_vector(31 downto 0);
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reg_data : std_ulogic_vector(63 downto 0);
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ispr : gspr_index_t;
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instr_addr : std_ulogic_vector(63 downto 0))
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return decode_input_reg_t is
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begin
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if t = RA or (t = RA_OR_ZERO and insn_ra(insn_in) /= "00000") then
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assert is_fast_spr(ispr) = '0' report "Decode A says GPR but ISPR says SPR:" &
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to_hstring(ispr) severity failure;
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return ('1', gpr_to_gspr(insn_ra(insn_in)), reg_data);
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elsif t = SPR then
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-- ISPR must be either a valid fast SPR number or all 0 for a slow SPR.
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-- If it's all 0, we don't treat it as a dependency as slow SPRs
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-- operations are single issue.
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--
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assert is_fast_spr(ispr) = '1' or ispr = "000000"
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report "Decode A says SPR but ISPR is invalid:" &
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to_hstring(ispr) severity failure;
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return (is_fast_spr(ispr), ispr, reg_data);
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elsif t = CIA then
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return ('0', (others => '0'), instr_addr);
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else
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return ('0', (others => '0'), (others => '0'));
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end if;
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end;
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function decode_input_reg_b (t : input_reg_b_t; insn_in : std_ulogic_vector(31 downto 0);
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reg_data : std_ulogic_vector(63 downto 0);
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ispr : gspr_index_t) return decode_input_reg_t is
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variable ret : decode_input_reg_t;
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begin
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case t is
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when RB =>
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assert is_fast_spr(ispr) = '0' report "Decode B says GPR but ISPR says SPR:" &
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to_hstring(ispr) severity failure;
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ret := ('1', gpr_to_gspr(insn_rb(insn_in)), reg_data);
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when CONST_UI =>
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ret := ('0', (others => '0'), std_ulogic_vector(resize(unsigned(insn_ui(insn_in)), 64)));
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when CONST_SI =>
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ret := ('0', (others => '0'), std_ulogic_vector(resize(signed(insn_si(insn_in)), 64)));
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when CONST_SI_HI =>
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ret := ('0', (others => '0'), std_ulogic_vector(resize(signed(insn_si(insn_in)) & x"0000", 64)));
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when CONST_UI_HI =>
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ret := ('0', (others => '0'), std_ulogic_vector(resize(unsigned(insn_si(insn_in)) & x"0000", 64)));
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when CONST_LI =>
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ret := ('0', (others => '0'), std_ulogic_vector(resize(signed(insn_li(insn_in)) & "00", 64)));
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when CONST_BD =>
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ret := ('0', (others => '0'), std_ulogic_vector(resize(signed(insn_bd(insn_in)) & "00", 64)));
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when CONST_DS =>
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ret := ('0', (others => '0'), std_ulogic_vector(resize(signed(insn_ds(insn_in)) & "00", 64)));
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when CONST_DXHI4 =>
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ret := ('0', (others => '0'), std_ulogic_vector(resize(signed(insn_dx(insn_in)) & x"0004", 64)));
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when CONST_M1 =>
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ret := ('0', (others => '0'), x"FFFFFFFFFFFFFFFF");
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when CONST_SH =>
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ret := ('0', (others => '0'), x"00000000000000" & "00" & insn_in(1) & insn_in(15 downto 11));
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when CONST_SH32 =>
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ret := ('0', (others => '0'), x"00000000000000" & "000" & insn_in(15 downto 11));
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when SPR =>
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-- ISPR must be either a valid fast SPR number or all 0 for a slow SPR.
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-- If it's all 0, we don't treat it as a dependency as slow SPRs
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-- operations are single issue.
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assert is_fast_spr(ispr) = '1' or ispr = "000000"
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report "Decode B says SPR but ISPR is invalid:" &
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to_hstring(ispr) severity failure;
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ret := (is_fast_spr(ispr), ispr, reg_data);
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when NONE =>
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ret := ('0', (others => '0'), (others => '0'));
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end case;
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return ret;
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end;
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function decode_input_reg_c (t : input_reg_c_t; insn_in : std_ulogic_vector(31 downto 0);
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reg_data : std_ulogic_vector(63 downto 0)) return decode_input_reg_t is
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begin
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case t is
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when RS =>
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return ('1', gpr_to_gspr(insn_rs(insn_in)), reg_data);
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when NONE =>
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return ('0', (others => '0'), (others => '0'));
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end case;
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end;
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function decode_output_reg (t : output_reg_a_t; insn_in : std_ulogic_vector(31 downto 0);
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ispr : gspr_index_t) return decode_output_reg_t is
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begin
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case t is
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when RT =>
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return ('1', gpr_to_gspr(insn_rt(insn_in)));
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when RA =>
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return ('1', gpr_to_gspr(insn_ra(insn_in)));
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when SPR =>
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-- ISPR must be either a valid fast SPR number or all 0 for a slow SPR.
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-- If it's all 0, we don't treat it as a dependency as slow SPRs
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-- operations are single issue.
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assert is_fast_spr(ispr) = '1' or ispr = "000000"
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report "Decode B says SPR but ISPR is invalid:" &
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to_hstring(ispr) severity failure;
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return (is_fast_spr(ispr), ispr);
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when NONE =>
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return ('0', "000000");
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end case;
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end;
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function decode_rc (t : rc_t; insn_in : std_ulogic_vector(31 downto 0)) return std_ulogic is
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begin
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case t is
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when RC =>
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return insn_rc(insn_in);
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when ONE =>
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return '1';
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when NONE =>
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return '0';
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end case;
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end;
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-- For now, use "rc" in the decode table to decide whether oe exists.
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-- This is not entirely correct architecturally: For mulhd and
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-- mulhdu, the OE field is reserved. It remains to be seen what an
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-- actual POWER9 does if we set it on those instructions, for now we
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-- test that further down when assigning to the multiplier oe input.
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--
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function decode_oe (t : rc_t; insn_in : std_ulogic_vector(31 downto 0)) return std_ulogic is
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begin
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case t is
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when RC =>
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return insn_oe(insn_in);
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when OTHERS =>
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return '0';
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end case;
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end;
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-- issue control signals
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signal control_valid_in : std_ulogic;
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signal control_valid_out : std_ulogic;
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signal control_sgl_pipe : std_logic;
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signal gpr_write_valid : std_ulogic;
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signal gpr_write : gspr_index_t;
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signal gpr_bypassable : std_ulogic;
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signal gpr_a_read_valid : std_ulogic;
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signal gpr_a_read :gspr_index_t;
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signal gpr_a_bypass : std_ulogic;
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signal gpr_b_read_valid : std_ulogic;
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signal gpr_b_read : gspr_index_t;
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signal gpr_b_bypass : std_ulogic;
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signal gpr_c_read_valid : std_ulogic;
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signal gpr_c_read : gpr_index_t;
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signal gpr_c_bypass : std_ulogic;
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signal cr_write_valid : std_ulogic;
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begin
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control_0: entity work.control
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generic map (
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PIPELINE_DEPTH => 1
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)
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port map (
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clk => clk,
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rst => rst,
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complete_in => complete_in,
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valid_in => control_valid_in,
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stall_in => stall_in,
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flush_in => flush_in,
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sgl_pipe_in => control_sgl_pipe,
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stop_mark_in => d_in.stop_mark,
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gpr_write_valid_in => gpr_write_valid,
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gpr_write_in => gpr_write,
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gpr_bypassable => gpr_bypassable,
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gpr_a_read_valid_in => gpr_a_read_valid,
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gpr_a_read_in => gpr_a_read,
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gpr_b_read_valid_in => gpr_b_read_valid,
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gpr_b_read_in => gpr_b_read,
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gpr_c_read_valid_in => gpr_c_read_valid,
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gpr_c_read_in => gpr_c_read,
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cr_read_in => d_in.decode.input_cr,
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cr_write_in => cr_write_valid,
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valid_out => control_valid_out,
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stall_out => stall_out,
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stopped_out => stopped_out,
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gpr_bypass_a => gpr_a_bypass,
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gpr_bypass_b => gpr_b_bypass,
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gpr_bypass_c => gpr_c_bypass
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);
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decode2_0: process(clk)
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begin
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if rising_edge(clk) then
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if rin.e.valid = '1' then
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report "execute " & to_hstring(rin.e.nia);
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end if;
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r <= rin;
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end if;
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end process;
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r_out.read1_reg <= gpr_or_spr_to_gspr(insn_ra(d_in.insn), d_in.ispr1);
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r_out.read2_reg <= gpr_or_spr_to_gspr(insn_rb(d_in.insn), d_in.ispr2);
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r_out.read3_reg <= insn_rs(d_in.insn);
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c_out.read <= d_in.decode.input_cr;
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decode2_1: process(all)
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variable v : reg_type;
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variable mul_a : std_ulogic_vector(63 downto 0);
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variable mul_b : std_ulogic_vector(63 downto 0);
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variable decoded_reg_a : decode_input_reg_t;
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variable decoded_reg_b : decode_input_reg_t;
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variable decoded_reg_c : decode_input_reg_t;
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variable decoded_reg_o : decode_output_reg_t;
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variable length : std_ulogic_vector(3 downto 0);
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begin
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v := r;
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v.e := Decode2ToExecute1Init;
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mul_a := (others => '0');
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mul_b := (others => '0');
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--v.e.input_cr := d_in.decode.input_cr;
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--v.e.output_cr := d_in.decode.output_cr;
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decoded_reg_a := decode_input_reg_a (d_in.decode.input_reg_a, d_in.insn, r_in.read1_data, d_in.ispr1,
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d_in.nia);
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decoded_reg_b := decode_input_reg_b (d_in.decode.input_reg_b, d_in.insn, r_in.read2_data, d_in.ispr2);
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decoded_reg_c := decode_input_reg_c (d_in.decode.input_reg_c, d_in.insn, r_in.read3_data);
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decoded_reg_o := decode_output_reg (d_in.decode.output_reg_a, d_in.insn, d_in.ispr1);
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r_out.read1_enable <= decoded_reg_a.reg_valid and d_in.valid;
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r_out.read2_enable <= decoded_reg_b.reg_valid and d_in.valid;
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r_out.read3_enable <= decoded_reg_c.reg_valid and d_in.valid;
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case d_in.decode.length is
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when is1B =>
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length := "0001";
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when is2B =>
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length := "0010";
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when is4B =>
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length := "0100";
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when is8B =>
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length := "1000";
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when NONE =>
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length := "0000";
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end case;
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-- execute unit
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v.e.nia := d_in.nia;
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v.e.unit := d_in.decode.unit;
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v.e.insn_type := d_in.decode.insn_type;
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v.e.read_reg1 := decoded_reg_a.reg;
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v.e.read_data1 := decoded_reg_a.data;
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v.e.bypass_data1 := gpr_a_bypass;
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v.e.read_reg2 := decoded_reg_b.reg;
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v.e.read_data2 := decoded_reg_b.data;
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v.e.bypass_data2 := gpr_b_bypass;
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v.e.read_data3 := decoded_reg_c.data;
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v.e.bypass_data3 := gpr_c_bypass;
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v.e.write_reg := decoded_reg_o.reg;
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v.e.rc := decode_rc(d_in.decode.rc, d_in.insn);
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if not (d_in.decode.insn_type = OP_MUL_H32 or d_in.decode.insn_type = OP_MUL_H64) then
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v.e.oe := decode_oe(d_in.decode.rc, d_in.insn);
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end if;
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v.e.cr := c_in.read_cr_data;
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v.e.xerc := c_in.read_xerc_data;
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v.e.invert_a := d_in.decode.invert_a;
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v.e.invert_out := d_in.decode.invert_out;
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v.e.input_carry := d_in.decode.input_carry;
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v.e.output_carry := d_in.decode.output_carry;
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v.e.is_32bit := d_in.decode.is_32bit;
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v.e.is_signed := d_in.decode.is_signed;
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if d_in.decode.lr = '1' then
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v.e.lr := insn_lk(d_in.insn);
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end if;
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v.e.insn := d_in.insn;
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v.e.data_len := length;
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v.e.byte_reverse := d_in.decode.byte_reverse;
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v.e.sign_extend := d_in.decode.sign_extend;
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v.e.update := d_in.decode.update;
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v.e.reserve := d_in.decode.reserve;
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-- issue control
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control_valid_in <= d_in.valid;
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control_sgl_pipe <= d_in.decode.sgl_pipe;
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gpr_write_valid <= decoded_reg_o.reg_valid;
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gpr_write <= decoded_reg_o.reg;
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gpr_bypassable <= '0';
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if EX1_BYPASS and d_in.decode.unit = ALU then
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gpr_bypassable <= '1';
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end if;
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gpr_a_read_valid <= decoded_reg_a.reg_valid;
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gpr_a_read <= decoded_reg_a.reg;
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gpr_b_read_valid <= decoded_reg_b.reg_valid;
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gpr_b_read <= decoded_reg_b.reg;
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gpr_c_read_valid <= decoded_reg_c.reg_valid;
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gpr_c_read <= gspr_to_gpr(decoded_reg_c.reg);
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cr_write_valid <= d_in.decode.output_cr or decode_rc(d_in.decode.rc, d_in.insn);
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v.e.valid := control_valid_out;
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if d_in.decode.unit = NONE then
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v.e.insn_type := OP_ILLEGAL;
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end if;
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if rst = '1' then
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v.e := Decode2ToExecute1Init;
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end if;
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-- Update registers
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rin <= v;
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-- Update outputs
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e_out <= r.e;
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end process;
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end architecture behaviour;
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