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-- Note: it is the cache module that does all internal address decoding --------
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-- Note: it is the cache module that does all internal address decoding --------
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-- This is the slice of the address that will be used to decode memory areas
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-- This is the slice of the address that will be used to decode memory areas
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subtype t_addr_decode is std_logic_vector(31 downto 24);
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subtype t_addr_decode is std_logic_vector(31 downto 24);
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-- 'Attributes' of some memory block -- used when decoding memory addresses
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-- type[3] : can_write[1] : cacheable[1] : delay_states[2]
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subtype t_range_attr is std_logic_vector(6 downto 0);
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-- Part of the memory area attribute: the type of memory determines how the
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-- Part of the memory area attribute: the type of memory determines how the
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-- cache module handles each block
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-- cache module handles each block
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subtype t_memory_type is std_logic_vector(2 downto 0);
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subtype t_memory_type is std_logic_vector(7 downto 5);
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-- These are all the types the cache knows about
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-- These are all the types the cache knows about
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constant MT_BRAM : t_memory_type := "000";
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constant MT_BRAM : t_memory_type := "000";
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constant MT_IO_SYNC : t_memory_type := "001";
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constant MT_IO_SYNC : t_memory_type := "001";
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constant MT_SRAM_16B : t_memory_type := "010";
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constant MT_SRAM_16B : t_memory_type := "010";
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constant MT_FLASH_16B : t_memory_type := "011";
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constant MT_FLASH_16B : t_memory_type := "011";
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constant MT_DDR_16B : t_memory_type := "100";
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constant MT_DDR_16B : t_memory_type := "100";
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constant MT_UNMAPPED : t_memory_type := "111";
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constant MT_UNMAPPED : t_memory_type := "111";
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-- Wait state counter -- we're supporting static memory from 10 to >100 ns
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subtype t_wait_state_count is std_logic_vector(2 downto 0);
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-- 'Attributes' of some memory block -- used when decoding memory addresses
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type t_range_attr is record
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mem_type : t_memory_type;
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writeable : std_logic;
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cacheable : std_logic;
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wait_states : t_wait_state_count;
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end record t_range_attr;
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---- More basic types and constants --------------------------------------------
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---- More basic types and constants --------------------------------------------
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subtype t_addr is std_logic_vector(31 downto 0);
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subtype t_addr is std_logic_vector(31 downto 0);
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subtype t_dword is std_logic_vector(63 downto 0);
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subtype t_dword is std_logic_vector(63 downto 0);
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-- Address decoding for Plasma-like system
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-- Address decoding for Plasma-like system
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function decode_addr_plasma(addr : t_addr_decode) return t_range_attr is
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function decode_addr_plasma(addr : t_addr_decode) return t_range_attr is
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begin
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begin
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case addr(31 downto 27) is
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case addr(31 downto 27) is
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when "00000" => return MT_BRAM &"0"&"0"&"00"; -- useg
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when "00000" => return (MT_BRAM ,'0','0',"000"); -- useg
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when "10000" => return MT_SRAM_16B &"1"&"1"&"00"; -- kseg0
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when "10000" => return (MT_SRAM_16B ,'1','1',"000"); -- kseg0
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when "00100" => return MT_IO_SYNC &"1"&"0"&"00"; -- kseg1 i/o
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when "00100" => return (MT_IO_SYNC ,'1','0',"000"); -- kseg1 i/o
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when others => return MT_UNMAPPED &"0"&"0"&"00"; -- stray
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when others => return (MT_UNMAPPED ,'0','0',"000"); -- stray
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end case;
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end case;
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end function decode_addr_plasma;
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end function decode_addr_plasma;
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-- Address decoding for MIPS-I-like system
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-- Address decoding for MIPS-I-like system
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function decode_addr_mips1(addr : t_addr_decode) return t_range_attr is
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function decode_addr_mips1(addr : t_addr_decode) return t_range_attr is
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begin
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begin
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case addr(31 downto 27) is
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case addr(31 downto 27) is
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when "00000" => return MT_SRAM_16B &"1"&"1"&"00"; -- useg
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when "00000" => return (MT_SRAM_16B ,'1','1',"011"); -- useg
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when "10000" => return MT_SRAM_16B &"1"&"1"&"00"; -- kseg0
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when "10000" => return (MT_SRAM_16B ,'1','1',"000"); -- kseg0
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--when "10100" => return MT_IO_SYNC &"1"&"0"&"00"; -- kseg1 i/o
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--when "10100" => return (MT_IO_SYNC ,'1','0',"000"); -- kseg1 i/o
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when "00100" => return MT_IO_SYNC &"1"&"0"&"00"; -- kseg1 i/o
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when "00100" => return (MT_IO_SYNC ,'1','0',"000"); -- kseg1 i/o
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when "10110" => return MT_FLASH_16B&"0"&"0"&"10"; -- kseg1 flash
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when "10110" => return (MT_FLASH_16B,'0','0',"011"); -- kseg1 flash
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when "10111" => return MT_BRAM &"0"&"0"&"00"; -- kseg1 boot rom
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when "10111" => return (MT_BRAM ,'0','0',"000"); -- kseg1 boot rom
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when others => return MT_UNMAPPED &"0"&"0"&"00"; -- stray
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when others => return (MT_UNMAPPED ,'0','0',"000"); -- stray
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end case;
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end case;
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end function decode_addr_mips1;
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end function decode_addr_mips1;
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