| Line 54... |
Line 54... |
-- data input --
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-- data input --
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rs1_i : in std_ulogic_vector(data_width_c-1 downto 0); -- rf source 1
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rs1_i : in std_ulogic_vector(data_width_c-1 downto 0); -- rf source 1
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rs2_i : in std_ulogic_vector(data_width_c-1 downto 0); -- rf source 2
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rs2_i : in std_ulogic_vector(data_width_c-1 downto 0); -- rf source 2
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pc2_i : in std_ulogic_vector(data_width_c-1 downto 0); -- delayed PC
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pc2_i : in std_ulogic_vector(data_width_c-1 downto 0); -- delayed PC
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imm_i : in std_ulogic_vector(data_width_c-1 downto 0); -- immediate
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imm_i : in std_ulogic_vector(data_width_c-1 downto 0); -- immediate
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csr_i : in std_ulogic_vector(data_width_c-1 downto 0); -- csr read data
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-- data output --
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-- data output --
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cmp_o : out std_ulogic_vector(1 downto 0); -- comparator status
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cmp_o : out std_ulogic_vector(1 downto 0); -- comparator status
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add_o : out std_ulogic_vector(data_width_c-1 downto 0); -- OPA + OPB
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add_o : out std_ulogic_vector(data_width_c-1 downto 0); -- OPA + OPB
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res_o : out std_ulogic_vector(data_width_c-1 downto 0); -- ALU result
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res_o : out std_ulogic_vector(data_width_c-1 downto 0); -- ALU result
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-- co-processor interface --
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-- co-processor interface --
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cp_opa_o : out std_ulogic_vector(data_width_c-1 downto 0); -- co-processor operand a
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cp_opb_o : out std_ulogic_vector(data_width_c-1 downto 0); -- co-processor operand b
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cp0_start_o : out std_ulogic; -- trigger co-processor 0
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cp0_start_o : out std_ulogic; -- trigger co-processor 0
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cp0_data_i : in std_ulogic_vector(data_width_c-1 downto 0); -- co-processor 0 result
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cp0_data_i : in std_ulogic_vector(data_width_c-1 downto 0); -- co-processor 0 result
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cp0_valid_i : in std_ulogic; -- co-processor 0 result valid
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cp0_valid_i : in std_ulogic; -- co-processor 0 result valid
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cp1_start_o : out std_ulogic; -- trigger co-processor 1
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cp1_start_o : out std_ulogic; -- trigger co-processor 1
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cp1_data_i : in std_ulogic_vector(data_width_c-1 downto 0); -- co-processor 1 result
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cp1_data_i : in std_ulogic_vector(data_width_c-1 downto 0); -- co-processor 1 result
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Line 113... |
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begin
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begin
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-- Operand Mux ----------------------------------------------------------------------------
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-- Operand Mux ----------------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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input_op_mux: process(ctrl_i, csr_i, pc2_i, rs1_i, rs2_i, imm_i)
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opa <= rs1_i when (ctrl_i(ctrl_alu_opa_mux_c) = '0') else pc2_i; -- operand a (first ALU input operand)
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begin
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opb <= rs2_i when (ctrl_i(ctrl_alu_opb_mux_c) = '0') else imm_i; -- operand b (second ALU input operand)
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-- operand a (first ALU input operand) --
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opc <= rs2_i when (ctrl_i(ctrl_alu_opc_mux_c) = '0') else imm_i; -- operand c (third ALU input operand for comparison and SUB)
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case ctrl_i(ctrl_alu_opa_mux_msb_c downto ctrl_alu_opa_mux_lsb_c) is
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when "00" => opa <= rs1_i;
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when "01" => opa <= pc2_i;
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when others => opa <= csr_i;
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end case;
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-- operand b (second ALU input operand) --
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if (ctrl_i(ctrl_alu_opb_mux_c) = '0') then
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opb <= rs2_i;
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else
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opb <= imm_i;
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end if;
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-- operand c (third ALU input operand for comparison and SUB) --
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if (ctrl_i(ctrl_alu_opc_mux_c) = '0') then
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opc <= rs2_i;
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else
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opc <= imm_i;
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end if;
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end process input_op_mux;
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-- Comparator Unit ------------------------------------------------------------------------
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-- Comparator Unit ------------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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-- less than (x < y) --
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-- less than (x < y) --
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cp1_start_o <= '0'; -- not yet implemented
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cp1_start_o <= '0'; -- not yet implemented
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-- co-processor operation running? --
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-- co-processor operation running? --
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cp_ctrl.halt <= cp_ctrl.busy or cp_ctrl.start;
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cp_ctrl.halt <= cp_ctrl.busy or cp_ctrl.start;
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-- co-processor operands --
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cp_opa_o <= opa;
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cp_opb_o <= opb;
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-- co-processor result --
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-- co-processor result --
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cp_res <= cp0_data_i or cp1_data_i; -- only the selcted cp may output data != 0
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cp_res <= cp0_data_i or cp1_data_i; -- only the selected cp may output data != 0
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-- ALU Function Select --------------------------------------------------------------------
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-- ALU Function Select --------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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-- -------------------------------------------------------------------------------------------
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alu_function_mux: process(ctrl_i, opa, opb, add_res, sub_res, cmp_less, shifter.sreg)
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alu_function_mux: process(ctrl_i, opa, opb, add_res, sub_res, cmp_less, shifter.sreg)
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begin
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begin
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case ctrl_i(ctrl_alu_cmd2_c downto ctrl_alu_cmd0_c) is
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case ctrl_i(ctrl_alu_cmd2_c downto ctrl_alu_cmd0_c) is
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when alu_cmd_xor_c => alu_res <= opa xor opb;
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when alu_cmd_xor_c => alu_res <= opa xor opb;
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when alu_cmd_or_c => alu_res <= opa or opb;
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when alu_cmd_or_c => alu_res <= opa or opb;
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when alu_cmd_and_c => alu_res <= opa and opb;
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when alu_cmd_and_c => alu_res <= opa and opb;
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when alu_cmd_bclr_c => alu_res <= opa and (not opb);
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when alu_cmd_movb_c => alu_res <= opb;
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when alu_cmd_sub_c => alu_res <= sub_res;
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when alu_cmd_sub_c => alu_res <= sub_res;
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when alu_cmd_add_c => alu_res <= add_res;
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when alu_cmd_add_c => alu_res <= add_res;
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when alu_cmd_shift_c => alu_res <= shifter.sreg;
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when alu_cmd_shift_c => alu_res <= shifter.sreg;
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when alu_cmd_slt_c => alu_res <= (others => '0'); alu_res(0) <= cmp_less;
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when alu_cmd_slt_c => alu_res <= (others => '0'); alu_res(0) <= cmp_less;
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when others => alu_res <= (others => '0'); -- undefined
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when others => alu_res <= (others => '0'); -- undefined
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