2 use IEEE.std_logic_1164.all;
3 use IEEE.numeric_std.all;
7 architecture behav of writeback_stage is
12 signal data_ram_read : word_t;
14 signal wb_reg, wb_reg_nxt : writeback_rec;
24 wb_reg_nxt.address(PHYS_DATA_ADDR_WIDTH+1 downto 2),
25 wb_reg_nxt.address(PHYS_DATA_ADDR_WIDTH+1 downto 2),
26 wb_reg_nxt.dmem_write_en,
32 syn: process(sys_clk, reset)
36 if (reset = RESET_VALUE) then
38 elsif rising_edge(sys_clk) then
44 -- type writeback_rec is record
45 -- address : in word_t; --ureg
46 -- dmem_en : in std_logic; --ureg (jump addr in mem or in address)
47 -- dmem_write_en : in std_logic; --ureg
48 -- hword_hl : in std_logic --ureg
53 shift_input: process(data_ram_read, address, dmem_en, dmem_write_en, hword_hl, wb_reg, result)
56 wb_reg_nxt.address <= address;
57 wb_reg_nxt.dmem_en <= dmem_en;
58 wb_reg_nxt.dmem_write_en <= dmem_write_en;
59 wb_reg_nxt.hword <= hword;
60 wb_reg_nxt.byte_s <= byte_s;
62 regfile_val <= result; --(others => '0');
64 if (wb_reg.dmem_en = '1' and wb_reg.dmem_write_en = '0') then -- ram read operation --alu_jmp = '0' and
65 regfile_val <= data_ram_read;
66 if (wb_reg.hword = '1') then
67 regfile_val <= (others => '0');
68 if (wb_reg.address(1) = '1') then
69 regfile_val(15 downto 0) <= data_ram_read(31 downto 16);
71 regfile_val(15 downto 0) <= data_ram_read(15 downto 0);
74 if (wb_reg.byte_s = '1') then
75 regfile_val <= (others => '0');
76 case wb_reg.address(1 downto 0) is
77 when "00" => regfile_val(7 downto 0) <= data_ram_read(7 downto 0);
78 when "01" => regfile_val(7 downto 0) <= data_ram_read(15 downto 8);
79 when "10" => regfile_val(7 downto 0) <= data_ram_read(23 downto 16);
80 when "11" => regfile_val(7 downto 0) <= data_ram_read(31 downto 24);
85 jump <= alu_jmp xor br_pred;
87 if ((alu_jmp and wb_reg.dmem_en) = '1') then
88 jump_addr <= data_ram_read;
93 -- result : in gp_register_t; --reg (alu result or jumpaddr)
94 -- result_addr : in gp_addr_t; --reg
95 -- address : in word_t; --ureg
96 -- alu_jmp : in std_logic; --reg
97 -- br_pred : in std_logic; --reg
98 -- write_en : in std_logic; --reg (register file)
99 -- dmem_en : in std_logic; --ureg (jump addr in mem or in result)
100 -- dmem_write_en : in std_logic; --ureg
101 -- hword : in std_logic --ureg
105 out_logic: process(write_en, result_addr)
109 reg_addr <= result_addr;