mips/types.vhd (774c7db) - mips_sys · BlinkenArea

types.vhd

LIBRARY ieee;
USE ieee.std_logic_1164.all;
USE ieee.numeric_std.all;

PACKAGE mips_types IS

-- operation
    TYPE t_op IS (
        op_none,
        op_alu, -- ALU operation
        op_j,   -- jump or branch
        op_l,   -- load
        op_s    -- store
    );

-- link (store return address in register)
    TYPE t_link IS (
        link_none,
        link_link  -- link
    );

-- compare mode
    TYPE t_cmp IS (
        cmp_none,
        cmp_eq,   -- equal
        cmp_gez,  -- greater or equal zero
        cmp_gtz,  -- greater than zero
        cmp_lez,  -- less or equal zero
        cmp_ltz,  -- less than zero
        cmp_ne    -- not equal
    );

-- ALU operation
    TYPE t_alu IS (
        alu_none,
        alu_add,  -- addition
        alu_and,  -- bitwise AND
        alu_nor,  -- bitwise NOR
        alu_or,   -- bitwise OR
        alu_sub,  -- subtraction
        alu_sll,  -- shift left logically
        alu_sra,  -- shift right arithmetically
        alu_srl,  -- shift right logically
        alu_slt,  -- set on less than
        alu_sltu, -- set on less than unsigned
        alu_up,   -- move to upper half
        alu_xor   -- bitwise XOR
    );

-- immediate usage
    TYPE t_imm IS (
        imm_none,
        imm_a,    -- "a" immediate
        imm_16se, -- 16 bit immediate, sign-extension
        imm_16ze, -- 16 bit immediate, zero-extension
        imm_26    -- 26 bit immediate
    );

-- load/store type
    TYPE t_ldst IS (
        ldst_none,
        ldst_b,  -- byte (sign-extension)
        ldst_bu, -- byte unsigned (zero-extension)
        ldst_h,  -- half word (16 bit) (sign-extension)
        ldst_hu, -- half word unsigned (16 bit) (zero-extension)
        ldst_w   -- word (32 bit)
    );

END PACKAGE;

mips_sys

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