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 generic ( EX1_BYPASS : boolean := true; HAS_FPU : boolean := true; -- Non-zero to enable log data collection LOG_LENGTH : natural := 0 ); port ( clk : in std_ulogic; rst : in std_ulogic; complete_in : in instr_tag_t; busy_in : in std_ulogic; stall_out : out std_ulogic; stopped_out : out std_ulogic; flush_in: in std_ulogic; d_in : in Decode1ToDecode2Type; e_out : out Decode2ToExecute1Type; r_in : in RegisterFileToDecode2Type; r_out : out Decode2ToRegisterFileType; c_in : in CrFileToDecode2Type; c_out : out Decode2ToCrFileType; execute_bypass : in bypass_data_t; execute_cr_bypass : in cr_bypass_data_t; log_out : out std_ulogic_vector(9 downto 0) ); end entity decode2; architecture behaviour of decode2 is type reg_type is record e : Decode2ToExecute1Type; repeat : std_ulogic; end record; signal r, rin : reg_type; signal deferred : std_ulogic; type decode_input_reg_t is record reg_valid : std_ulogic; reg : gspr_index_t; data : std_ulogic_vector(63 downto 0); end record; type decode_output_reg_t is record reg_valid : std_ulogic; reg : gspr_index_t; 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); ispr : gspr_index_t; instr_addr : std_ulogic_vector(63 downto 0)) return decode_input_reg_t is begin if t = RA or (t = RA_OR_ZERO and insn_ra(insn_in) /= "00000") then return ('1', gpr_to_gspr(insn_ra(insn_in)), reg_data); elsif t = SPR then -- ISPR must be either a valid fast SPR number or all 0 for a slow SPR. -- If it's all 0, we don't treat it as a dependency as slow SPRs -- operations are single issue. -- assert is_fast_spr(ispr) = '1' or ispr = "0000000" report "Decode A says SPR but ISPR is invalid:" & to_hstring(ispr) severity failure; return (is_fast_spr(ispr), ispr, reg_data); elsif t = CIA then return ('0', (others => '0'), instr_addr); elsif HAS_FPU and t = FRA then return ('1', fpr_to_gspr(insn_fra(insn_in)), reg_data); else return ('0', (others => '0'), (others => '0')); end if; 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); ispr : gspr_index_t) return decode_input_reg_t is variable ret : decode_input_reg_t; begin case t is when RB => ret := ('1', gpr_to_gspr(insn_rb(insn_in)), reg_data); when FRB => if HAS_FPU then ret := ('1', fpr_to_gspr(insn_frb(insn_in)), reg_data); else ret := ('0', (others => '0'), (others => '0')); end if; when CONST_UI => ret := ('0', (others => '0'), std_ulogic_vector(resize(unsigned(insn_ui(insn_in)), 64))); when CONST_SI => ret := ('0', (others => '0'), std_ulogic_vector(resize(signed(insn_si(insn_in)), 64))); when CONST_SI_HI => ret := ('0', (others => '0'), std_ulogic_vector(resize(signed(insn_si(insn_in)) & x"0000", 64))); when CONST_UI_HI => ret := ('0', (others => '0'), std_ulogic_vector(resize(unsigned(insn_si(insn_in)) & x"0000", 64))); when CONST_LI => ret := ('0', (others => '0'), std_ulogic_vector(resize(signed(insn_li(insn_in)) & "00", 64))); when CONST_BD => ret := ('0', (others => '0'), std_ulogic_vector(resize(signed(insn_bd(insn_in)) & "00", 64))); when CONST_DS => ret := ('0', (others => '0'), std_ulogic_vector(resize(signed(insn_ds(insn_in)) & "00", 64))); when CONST_DQ => ret := ('0', (others => '0'), std_ulogic_vector(resize(signed(insn_dq(insn_in)) & "0000", 64))); when CONST_DXHI4 => ret := ('0', (others => '0'), std_ulogic_vector(resize(signed(insn_dx(insn_in)) & x"0004", 64))); when CONST_M1 => ret := ('0', (others => '0'), x"FFFFFFFFFFFFFFFF"); when CONST_SH => ret := ('0', (others => '0'), x"00000000000000" & "00" & insn_in(1) & insn_in(15 downto 11)); when CONST_SH32 => ret := ('0', (others => '0'), x"00000000000000" & "000" & insn_in(15 downto 11)); when SPR => -- ISPR must be either a valid fast SPR number or all 0 for a slow SPR. -- If it's all 0, we don't treat it as a dependency as slow SPRs -- operations are single issue. assert is_fast_spr(ispr) = '1' or ispr = "0000000" report "Decode B says SPR but ISPR is invalid:" & to_hstring(ispr) severity failure; ret := (is_fast_spr(ispr), ispr, reg_data); when NONE => ret := ('0', (others => '0'), (others => '0')); end case; return ret; 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', gpr_to_gspr(insn_rs(insn_in)), reg_data); when RCR => return ('1', gpr_to_gspr(insn_rcreg(insn_in)), reg_data); when FRS => if HAS_FPU then return ('1', fpr_to_gspr(insn_frt(insn_in)), reg_data); else return ('0', (others => '0'), (others => '0')); end if; when FRC => if HAS_FPU then return ('1', fpr_to_gspr(insn_frc(insn_in)), reg_data); else return ('0', (others => '0'), (others => '0')); end if; 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); ispr : gspr_index_t) return decode_output_reg_t is begin case t is when RT => return ('1', gpr_to_gspr(insn_rt(insn_in))); when RA => return ('1', gpr_to_gspr(insn_ra(insn_in))); when FRT => if HAS_FPU then return ('1', fpr_to_gspr(insn_frt(insn_in))); else return ('0', "0000000"); end if; when SPR => -- ISPR must be either a valid fast SPR number or all 0 for a slow SPR. -- If it's all 0, we don't treat it as a dependency as slow SPRs -- operations are single issue. assert is_fast_spr(ispr) = '1' or ispr = "0000000" report "Decode B says SPR but ISPR is invalid:" & to_hstring(ispr) severity failure; return (is_fast_spr(ispr), ispr); when NONE => return ('0', "0000000"); 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; -- control signals that are derived from insn_type type mux_select_array_t is array(insn_type_t) of std_ulogic_vector(2 downto 0); constant result_select : mux_select_array_t := ( OP_AND => "001", -- logical_result OP_OR => "001", OP_XOR => "001", OP_PRTY => "001", OP_CMPB => "001", OP_EXTS => "001", OP_BPERM => "001", OP_BCD => "001", OP_MTSPR => "001", OP_RLC => "010", -- rotator_result OP_RLCL => "010", OP_RLCR => "010", OP_SHL => "010", OP_SHR => "010", OP_EXTSWSLI => "010", OP_MUL_L64 => "011", -- muldiv_result OP_MFSPR => "101", -- spr_result OP_B => "110", -- next_nia OP_BC => "110", OP_BCREG => "110", OP_ADDG6S => "111", -- misc_result OP_ISEL => "111", OP_DARN => "111", OP_MFMSR => "111", OP_MFCR => "111", OP_SETB => "111", others => "000" -- default to adder_result ); constant subresult_select : mux_select_array_t := ( OP_MUL_L64 => "000", -- muldiv_result OP_MUL_H64 => "001", OP_MUL_H32 => "010", OP_DIV => "011", OP_DIVE => "011", OP_MOD => "011", OP_ADDG6S => "001", -- misc_result OP_ISEL => "010", OP_DARN => "011", OP_MFMSR => "100", OP_MFCR => "101", OP_SETB => "110", OP_CMP => "000", -- cr_result OP_CMPRB => "001", OP_CMPEQB => "010", OP_CROP => "011", OP_MCRXRX => "100", OP_MTCRF => "101", others => "000" ); -- issue control signals signal control_valid_in : std_ulogic; signal control_valid_out : std_ulogic; signal control_stall_out : std_ulogic; signal control_sgl_pipe : std_logic; signal gpr_write_valid : std_ulogic; signal gpr_write : gspr_index_t; signal gpr_a_read_valid : std_ulogic; signal gpr_a_read : gspr_index_t; signal gpr_a_bypass : std_ulogic; signal gpr_b_read_valid : std_ulogic; signal gpr_b_read : gspr_index_t; signal gpr_b_bypass : std_ulogic; signal gpr_c_read_valid : std_ulogic; signal gpr_c_read : gspr_index_t; signal gpr_c_bypass : std_ulogic; signal cr_read_valid : std_ulogic; signal cr_write_valid : std_ulogic; signal cr_bypass : std_ulogic; signal instr_tag : instr_tag_t; begin control_0: entity work.control generic map ( EX1_BYPASS => EX1_BYPASS ) port map ( clk => clk, rst => rst, complete_in => complete_in, valid_in => control_valid_in, repeated => r.repeat, busy_in => busy_in, deferred => deferred, flush_in => flush_in, sgl_pipe_in => control_sgl_pipe, stop_mark_in => d_in.stop_mark, gpr_write_valid_in => gpr_write_valid, gpr_write_in => gpr_write, gpr_a_read_valid_in => gpr_a_read_valid, gpr_a_read_in => gpr_a_read, gpr_b_read_valid_in => gpr_b_read_valid, gpr_b_read_in => gpr_b_read, gpr_c_read_valid_in => gpr_c_read_valid, gpr_c_read_in => gpr_c_read, execute_next_tag => execute_bypass.tag, execute_next_cr_tag => execute_cr_bypass.tag, cr_read_in => cr_read_valid, cr_write_in => cr_write_valid, cr_bypass => cr_bypass, valid_out => control_valid_out, stall_out => control_stall_out, stopped_out => stopped_out, gpr_bypass_a => gpr_a_bypass, gpr_bypass_b => gpr_b_bypass, gpr_bypass_c => gpr_c_bypass, instr_tag_out => instr_tag ); deferred <= r.e.valid and busy_in; decode2_0: process(clk) begin if rising_edge(clk) then if rst = '1' or flush_in = '1' or deferred = '0' then if rin.e.valid = '1' then report "execute " & to_hstring(rin.e.nia); end if; r <= rin; end if; end if; end process; c_out.read <= d_in.decode.input_cr; decode2_1: process(all) variable v : reg_type; 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; variable decoded_reg_o : decode_output_reg_t; variable length : std_ulogic_vector(3 downto 0); variable op : insn_type_t; begin v := r; v.e := Decode2ToExecute1Init; mul_a := (others => '0'); mul_b := (others => '0'); --v.e.input_cr := d_in.decode.input_cr; v.e.output_cr := d_in.decode.output_cr; -- Work out whether XER common bits are set v.e.output_xer := d_in.decode.output_carry; case d_in.decode.insn_type is when OP_ADD | OP_MUL_L64 | OP_DIV | OP_DIVE => -- OE field is valid in OP_ADD/OP_MUL_L64 with major opcode 31 only if d_in.insn(31 downto 26) = "011111" and insn_oe(d_in.insn) = '1' then v.e.oe := '1'; v.e.output_xer := '1'; end if; when OP_MTSPR => if decode_spr_num(d_in.insn) = SPR_XER then v.e.output_xer := '1'; end if; when others => end case; decoded_reg_a := decode_input_reg_a (d_in.decode.input_reg_a, d_in.insn, r_in.read1_data, d_in.ispr1, d_in.nia); decoded_reg_b := decode_input_reg_b (d_in.decode.input_reg_b, d_in.insn, r_in.read2_data, d_in.ispr2); decoded_reg_c := decode_input_reg_c (d_in.decode.input_reg_c, d_in.insn, r_in.read3_data); decoded_reg_o := decode_output_reg (d_in.decode.output_reg_a, d_in.insn, d_in.ispro); if d_in.decode.lr = '1' then v.e.lr := insn_lk(d_in.insn); -- b and bc have even major opcodes; bcreg is considered absolute v.e.br_abs := insn_aa(d_in.insn) or d_in.insn(26); end if; op := d_in.decode.insn_type; if d_in.decode.repeat /= NONE then v.e.repeat := '1'; v.e.second := r.repeat; case d_in.decode.repeat is when DRSE => -- do RS|1,RS for LE; RS,RS|1 for BE if r.repeat = d_in.big_endian then decoded_reg_c.reg(0) := '1'; end if; when DRTE => -- do RT|1,RT for LE; RT,RT|1 for BE if r.repeat = d_in.big_endian then decoded_reg_o.reg(0) := '1'; end if; when DUPD => -- update-form loads, 2nd instruction writes RA if r.repeat = '1' then decoded_reg_o.reg := decoded_reg_a.reg; end if; when others => end case; elsif v.e.lr = '1' and decoded_reg_a.reg_valid = '1' then -- bcl/bclrl/bctarl that needs to write both CTR and LR has to be doubled v.e.repeat := '1'; v.e.second := r.repeat; -- first one does CTR, second does LR decoded_reg_o.reg(0) := not r.repeat; end if; v.e.spr_select := d_in.spr_info; r_out.read1_enable <= decoded_reg_a.reg_valid and d_in.valid; r_out.read1_reg <= decoded_reg_a.reg; r_out.read2_enable <= decoded_reg_b.reg_valid and d_in.valid; r_out.read2_reg <= decoded_reg_b.reg; r_out.read3_enable <= decoded_reg_c.reg_valid and d_in.valid; r_out.read3_reg <= decoded_reg_c.reg; case d_in.decode.length is when is1B => length := "0001"; when is2B => length := "0010"; when is4B => length := "0100"; when is8B => length := "1000"; when NONE => length := "0000"; end case; -- execute unit v.e.nia := d_in.nia; v.e.unit := d_in.decode.unit; v.e.fac := d_in.decode.facility; v.e.instr_tag := instr_tag; v.e.read_reg1 := decoded_reg_a.reg; v.e.read_reg2 := decoded_reg_b.reg; v.e.write_reg := decoded_reg_o.reg; v.e.write_reg_enable := decoded_reg_o.reg_valid; v.e.rc := decode_rc(d_in.decode.rc, d_in.insn); v.e.xerc := c_in.read_xerc_data; v.e.invert_a := d_in.decode.invert_a; v.e.addm1 := '0'; v.e.insn_type := op; v.e.invert_out := d_in.decode.invert_out; v.e.input_carry := d_in.decode.input_carry; v.e.output_carry := d_in.decode.output_carry; v.e.is_32bit := d_in.decode.is_32bit; v.e.is_signed := d_in.decode.is_signed; v.e.insn := d_in.insn; v.e.data_len := length; v.e.byte_reverse := d_in.decode.byte_reverse; v.e.sign_extend := d_in.decode.sign_extend; v.e.update := d_in.decode.update; v.e.reserve := d_in.decode.reserve; v.e.br_pred := d_in.br_pred; v.e.result_sel := result_select(op); v.e.sub_select := subresult_select(op); if op = OP_BC or op = OP_BCREG then if d_in.insn(23) = '0' and r.repeat = '0' and not (d_in.decode.insn_type = OP_BCREG and d_in.insn(10) = '0') then -- decrement CTR if BO(2) = 0 and not bcctr v.e.addm1 := '1'; v.e.result_sel := "000"; -- select adder output end if; end if; if op = OP_MFSPR then if is_fast_spr(d_in.ispr1) = '1' then v.e.result_sel := "000"; -- adder_result, effectively a_in elsif d_in.spr_info.valid = '0' then -- Privileged mfspr to invalid/unimplemented SPR numbers -- writes the contents of RT back to RT (i.e. it's a no-op) v.e.result_sel := "001"; -- logical_result elsif d_in.spr_info.ispmu = '1' then v.e.result_sel := "100"; -- pmuspr_result end if; end if; -- See if any of the operands can get their value via the bypass path. case gpr_a_bypass is when '1' => v.e.read_data1 := execute_bypass.data; when others => v.e.read_data1 := decoded_reg_a.data; end case; case gpr_b_bypass is when '1' => v.e.read_data2 := execute_bypass.data; when others => v.e.read_data2 := decoded_reg_b.data; end case; case gpr_c_bypass is when '1' => v.e.read_data3 := execute_bypass.data; when others => v.e.read_data3 := decoded_reg_c.data; end case; v.e.cr := c_in.read_cr_data; if cr_bypass = '1' then v.e.cr := execute_cr_bypass.data; end if; -- issue control control_valid_in <= d_in.valid; control_sgl_pipe <= d_in.decode.sgl_pipe; gpr_write_valid <= v.e.write_reg_enable; gpr_write <= decoded_reg_o.reg; gpr_a_read_valid <= decoded_reg_a.reg_valid; gpr_a_read <= decoded_reg_a.reg; gpr_b_read_valid <= decoded_reg_b.reg_valid; gpr_b_read <= decoded_reg_b.reg; gpr_c_read_valid <= decoded_reg_c.reg_valid; gpr_c_read <= decoded_reg_c.reg; cr_write_valid <= d_in.decode.output_cr or decode_rc(d_in.decode.rc, d_in.insn); -- Since ops that write CR only write some of the fields, -- any op that writes CR effectively also reads it. cr_read_valid <= cr_write_valid or d_in.decode.input_cr; v.e.valid := control_valid_out; if control_valid_out = '1' then v.repeat := v.e.repeat and not r.repeat; end if; stall_out <= control_stall_out or v.repeat; if rst = '1' or flush_in = '1' then v.e := Decode2ToExecute1Init; v.repeat := '0'; end if; -- Update registers rin <= v; -- Update outputs e_out <= r.e; end process; d2_log: if LOG_LENGTH > 0 generate signal log_data : std_ulogic_vector(9 downto 0); begin dec2_log : process(clk) begin if rising_edge(clk) then log_data <= r.e.nia(5 downto 2) & r.e.valid & stopped_out & stall_out & gpr_a_bypass & gpr_b_bypass & gpr_c_bypass; end if; end process; log_out <= log_data; end generate; end architecture behaviour;