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authoroharboe <oharboe>2008-05-01 08:20:02 +0000
committeroharboe <oharboe>2008-05-01 08:20:02 +0000
commit30faee20f811215e6d53ca2434119aa5cd059feb (patch)
tree05311c41ed61f35cd7e894d925c38312f61a1e58 /zpu/hdl/zpu4/src
parent7a1fb6dbe419749a2acf4ce583d7732480264ba6 (diff)
downloadzpu-30faee20f811215e6d53ca2434119aa5cd059feb.zip
zpu-30faee20f811215e6d53ca2434119aa5cd059feb.tar.gz
work in progress.
Diffstat (limited to 'zpu/hdl/zpu4/src')
-rw-r--r--zpu/hdl/zpu4/src/zpu_core_wip.vhd948
1 files changed, 948 insertions, 0 deletions
diff --git a/zpu/hdl/zpu4/src/zpu_core_wip.vhd b/zpu/hdl/zpu4/src/zpu_core_wip.vhd
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+++ b/zpu/hdl/zpu4/src/zpu_core_wip.vhd
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+
+-- Company: ZPU4 generic memory interface CPU
+-- Engineer: Řyvind Harboe
+
+library IEEE;
+use IEEE.STD_LOGIC_1164.ALL;
+use IEEE.STD_LOGIC_UNSIGNED.ALL;
+use IEEE.STD_LOGIC_arith.ALL;
+
+library work;
+use work.zpu_config.all;
+use work.zpupkg.all;
+
+
+
+
+
+entity zpu_core is
+ Port ( clk : in std_logic;
+ areset : in std_logic;
+ enable : in std_logic;
+ mem_req : out std_logic;
+ mem_we : out std_logic;
+ mem_ack : in std_logic;
+ mem_read : in std_logic_vector(wordSize-1 downto 0);
+ mem_write : out std_logic_vector(wordSize-1 downto 0);
+ out_mem_addr : out std_logic_vector(maxAddrBitIncIO downto 0);
+ mem_writeMask: out std_logic_vector(wordBytes-1 downto 0);
+ interrupt : in std_logic;
+ break : out std_logic;
+ zpu_status : out std_logic_vector(63 downto 0));
+end zpu_core;
+
+architecture behave of zpu_core is
+
+type InsnType is
+(
+State_AddTop,
+State_Dup,
+State_DupStackB,
+State_Pop,
+State_Popdown,
+State_Add,
+State_Or,
+State_And,
+State_Store,
+State_AddSP,
+State_Shift,
+State_Nop,
+State_Im,
+State_LoadSP,
+State_StoreSP,
+State_Emulate,
+State_Load,
+State_PushPC,
+State_PushSP,
+State_PopPC,
+State_PopPCRel,
+State_Not,
+State_Flip,
+State_PopSP,
+State_Neqbranch,
+State_Eq,
+State_Loadb,
+State_Mult,
+State_Lessthan,
+State_Lessthanorequal,
+State_Ulessthanorequal,
+State_Ulessthan,
+State_Pushspadd,
+State_Call,
+State_Callpcrel,
+State_Sub,
+State_Break,
+State_Storeb,
+State_Interrupt,
+State_InsnFetch
+);
+
+type StateType is
+(
+State_Idle, -- using first state first on the list out of paranoia
+State_Load2,
+State_Popped,
+State_LoadSP2,
+State_LoadSP3,
+State_AddSP2,
+State_Fetch,
+State_Execute,
+State_Decode,
+State_Decode2,
+State_Resync,
+
+State_StoreSP2,
+State_Resync2,
+State_Resync3,
+State_Loadb2,
+State_Storeb2,
+State_Mult2,
+State_Mult3,
+State_Mult5,
+State_Mult6,
+State_Mult4,
+State_BinaryOpResult
+);
+
+
+signal pc : std_logic_vector(maxAddrBitIncIO downto 0);
+signal sp : std_logic_vector(maxAddrBitIncIO downto minAddrBit);
+signal incSp : std_logic_vector(maxAddrBitIncIO downto minAddrBit);
+signal incIncSp : std_logic_vector(maxAddrBitIncIO downto minAddrBit);
+signal decSp : std_logic_vector(maxAddrBitIncIO downto minAddrBit);
+signal stackA : std_logic_vector(wordSize-1 downto 0);
+signal binaryOpResult : std_logic_vector(wordSize-1 downto 0);
+signal multResult2 : std_logic_vector(wordSize-1 downto 0);
+signal multResult3 : std_logic_vector(wordSize-1 downto 0);
+signal multResult : std_logic_vector(wordSize-1 downto 0);
+signal multA : std_logic_vector(wordSize-1 downto 0);
+signal multB : std_logic_vector(wordSize-1 downto 0);
+signal stackB : std_logic_vector(wordSize-1 downto 0);
+signal idim_flag : std_logic;
+signal busy : std_logic;
+signal mem_readEnable : std_logic;
+signal mem_addr : std_logic_vector(maxAddrBitIncIO downto minAddrBit);
+signal mem_delayAddr : std_logic_vector(maxAddrBitIncIO downto minAddrBit);
+signal mem_delayReadEnable : std_logic;
+signal mem_busy : std_logic;
+signal decodeWord : std_logic_vector(wordSize-1 downto 0);
+
+
+signal state : StateType;
+signal insn : InsnType;
+type InsnArray is array(0 to wordBytes-1) of InsnType;
+signal decodedOpcode : InsnArray;
+
+type OpcodeArray is array(0 to wordBytes-1) of std_logic_vector(7 downto 0);
+
+signal opcode : OpcodeArray;
+
+
+
+
+signal begin_inst : std_logic;
+signal trace_opcode : std_logic_vector(7 downto 0);
+signal trace_pc : std_logic_vector(maxAddrBitIncIO downto 0);
+signal trace_sp : std_logic_vector(maxAddrBitIncIO downto minAddrBit);
+signal trace_topOfStack : std_logic_vector(wordSize-1 downto 0);
+signal trace_topOfStackB : std_logic_vector(wordSize-1 downto 0);
+
+signal out_mem_req : std_logic;
+
+signal inInterrupt : std_logic;
+
+-- state machine.
+
+begin
+
+ zpu_status(maxAddrBitIncIO downto 0) <= trace_pc;
+ zpu_status(31) <= '1';
+ zpu_status(39 downto 32) <= trace_opcode;
+ zpu_status(40) <= '1' when (state = State_Idle) else '0';
+ zpu_status(62) <= '1';
+
+ traceFileGenerate:
+ if Generate_Trace generate
+ trace_file: trace port map (
+ clk => clk,
+ begin_inst => begin_inst,
+ pc => trace_pc,
+ opcode => trace_opcode,
+ sp => trace_sp,
+ memA => trace_topOfStack,
+ memB => trace_topOfStackB,
+ busy => busy,
+ intsp => (others => 'U')
+ );
+ end generate;
+
+
+ -- the memory subsystem will tell us one cycle later whether or
+ -- not it is busy
+ out_mem_addr(maxAddrBitIncIO downto minAddrBit) <= mem_addr;
+ out_mem_addr(minAddrBit-1 downto 0) <= (others => '0');
+ mem_req <= out_mem_req;
+
+ incSp <= sp + 1;
+ incIncSp <= sp + 2;
+ decSp <= sp - 1;
+
+ mem_busy <= out_mem_req and not mem_ack; -- '1' when the memory is busy
+
+ opcodeControl:
+ process(clk, areset)
+ variable tOpcode : std_logic_vector(OpCode_Size-1 downto 0);
+ variable spOffset : std_logic_vector(4 downto 0);
+ variable tSpOffset : std_logic_vector(4 downto 0);
+ variable nextPC : std_logic_vector(maxAddrBitIncIO downto 0);
+ variable tNextState : InsnType;
+ variable tDecodedOpcode : InsnArray;
+ variable tMultResult : std_logic_vector(wordSize*2-1 downto 0);
+ begin
+ if areset = '1' then
+ state <= State_Idle;
+ break <= '0';
+ sp <= spStart(maxAddrBitIncIO downto minAddrBit);
+
+ pc <= (others => '0');
+ idim_flag <= '0';
+ begin_inst <= '0';
+ mem_we <= '0';
+ multA <= (others => '0');
+ multB <= (others => '0');
+ mem_writeMask <= (others => '1');
+ out_mem_req <= '0';
+ mem_addr <= (others => DontCareValue);
+ mem_write <= (others => DontCareValue);
+ inInterrupt <= '0';
+ elsif (clk'event and clk = '1') then
+ -- we must multiply unconditionally to get pipelined multiplication
+ tMultResult := multA * multB;
+ multResult3 <= multResult2;
+ multResult2 <= multResult;
+ multResult <= tMultResult(wordSize-1 downto 0);
+
+
+ spOffset(4):=not opcode(conv_integer(pc(byteBits-1 downto 0)))(4);
+ spOffset(3 downto 0):=opcode(conv_integer(pc(byteBits-1 downto 0)))(3 downto 0);
+ nextPC := pc + 1;
+
+ -- prepare trace snapshot
+ trace_opcode <= opcode(conv_integer(pc(byteBits-1 downto 0)));
+ trace_pc <= pc;
+ trace_sp <= sp;
+ trace_topOfStack <= stackA;
+ trace_topOfStackB <= stackB;
+ begin_inst <= '0';
+
+ -- we terminate the requeset as soon as we get acknowledge
+ if mem_ack = '1' then
+ out_mem_req <= '0';
+ mem_we <= '0';
+ end if;
+
+ if interrupt='0' then
+ inInterrupt <= '0'; -- no longer in an interrupt
+ end if;
+
+ case state is
+ when State_Idle =>
+ if enable='1' then
+ state <= State_Resync;
+ end if;
+ -- Initial state of ZPU, fetch top of stack + first instruction
+ when State_Resync =>
+ if mem_busy='0' then
+ mem_addr <= sp;
+ out_mem_req <= '1';
+ state <= State_Resync2;
+ end if;
+ when State_Resync2 =>
+ if mem_busy='0' then
+ stackA <= mem_read;
+ mem_addr <= incSp;
+ out_mem_req <= '1';
+ state <= State_Resync3;
+ end if;
+ when State_Resync3 =>
+ if mem_busy='0' then
+ stackB <= mem_read;
+ mem_addr <= pc(maxAddrBitIncIO downto minAddrBit);
+ out_mem_req <= '1';
+ state <= State_Decode;
+ end if;
+ when State_Decode =>
+ if mem_busy='0' then
+ decodeWord <= mem_read;
+ state <= State_Decode2;
+ end if;
+ when State_Decode2 =>
+ -- decode 4 instructions in parallel
+ for i in 0 to wordBytes-1 loop
+ tOpcode := decodeWord((wordBytes-1-i+1)*8-1 downto (wordBytes-1-i)*8);
+
+ tSpOffset(4):=not tOpcode(4);
+ tSpOffset(3 downto 0):=tOpcode(3 downto 0);
+
+ opcode(i) <= tOpcode;
+ if (tOpcode(7 downto 7)=OpCode_Im) then
+ tNextState:=State_Im;
+ elsif (tOpcode(7 downto 5)=OpCode_StoreSP) then
+ if tSpOffset = 0 then
+ tNextState := State_Pop;
+ elsif tSpOffset=1 then
+ tNextState := State_PopDown;
+ else
+ tNextState :=State_StoreSP;
+ end if;
+ elsif (tOpcode(7 downto 5)=OpCode_LoadSP) then
+ if tSpOffset = 0 then
+ tNextState :=State_Dup;
+ elsif tSpOffset = 1 then
+ tNextState :=State_DupStackB;
+ else
+ tNextState :=State_LoadSP;
+ end if;
+ elsif (tOpcode(7 downto 5)=OpCode_Emulate) then
+ tNextState :=State_Emulate;
+ if tOpcode(5 downto 0)=OpCode_Neqbranch then
+ tNextState :=State_Neqbranch;
+ elsif tOpcode(5 downto 0)=OpCode_Eq then
+ tNextState :=State_Eq;
+ elsif tOpcode(5 downto 0)=OpCode_Lessthan then
+ tNextState :=State_Lessthan;
+ elsif tOpcode(5 downto 0)=OpCode_Lessthanorequal then
+ --tNextState :=State_Lessthanorequal;
+ elsif tOpcode(5 downto 0)=OpCode_Ulessthan then
+ tNextState :=State_Ulessthan;
+ elsif tOpcode(5 downto 0)=OpCode_Ulessthanorequal then
+ --tNextState :=State_Ulessthanorequal;
+ elsif tOpcode(5 downto 0)=OpCode_Loadb then
+ tNextState :=State_Loadb;
+ elsif tOpcode(5 downto 0)=OpCode_Mult then
+ tNextState :=State_Mult;
+ elsif tOpcode(5 downto 0)=OpCode_Storeb then
+ tNextState :=State_Storeb;
+ elsif tOpcode(5 downto 0)=OpCode_Pushspadd then
+ tNextState :=State_Pushspadd;
+ elsif tOpcode(5 downto 0)=OpCode_Callpcrel then
+ tNextState :=State_Callpcrel;
+ elsif tOpcode(5 downto 0)=OpCode_Call then
+ --tNextState :=State_Call;
+ elsif tOpcode(5 downto 0)=OpCode_Sub then
+ tNextState :=State_Sub;
+ elsif tOpcode(5 downto 0)=OpCode_PopPCRel then
+ --tNextState :=State_PopPCRel;
+ end if;
+ elsif (tOpcode(7 downto 4)=OpCode_AddSP) then
+ if tSpOffset = 0 then
+ tNextState := State_Shift;
+ elsif tSpOffset = 1 then
+ tNextState := State_AddTop;
+ else
+ tNextState :=State_AddSP;
+ end if;
+ else
+ case tOpcode(3 downto 0) is
+ when OpCode_Nop =>
+ tNextState :=State_Nop;
+ when OpCode_PushSP =>
+ tNextState :=State_PushSP;
+ when OpCode_PopPC =>
+ tNextState :=State_PopPC;
+ when OpCode_Add =>
+ tNextState :=State_Add;
+ when OpCode_Or =>
+ tNextState :=State_Or;
+ when OpCode_And =>
+ tNextState :=State_And;
+ when OpCode_Load =>
+ tNextState :=State_Load;
+ when OpCode_Not =>
+ tNextState :=State_Not;
+ when OpCode_Flip =>
+ tNextState :=State_Flip;
+ when OpCode_Store =>
+ tNextState :=State_Store;
+ when OpCode_PopSP =>
+ tNextState :=State_PopSP;
+ when others =>
+ tNextState := State_Break;
+
+ end case;
+ end if;
+ tDecodedOpcode(i) := tNextState;
+
+ end loop;
+
+ insn <= tDecodedOpcode(conv_integer(pc(byteBits-1 downto 0)));
+
+ -- once we wrap, we need to fetch
+ tDecodedOpcode(0) := State_InsnFetch;
+
+ decodedOpcode <= tDecodedOpcode;
+ state <= State_Execute;
+
+
+
+ -- Each instruction must:
+ --
+ -- 1. set idim_flag
+ -- 2. increase pc if applicable
+ -- 3. set next state if appliable
+ -- 4. do it's operation
+
+ when State_Execute =>
+ insn <= decodedOpcode(conv_integer(nextPC(byteBits-1 downto 0)));
+
+ case insn is
+ when State_InsnFetch =>
+ state <= State_Fetch;
+ when State_Im =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '1';
+ pc <= pc + 1;
+
+ if idim_flag='1' then
+ stackA(wordSize-1 downto 7) <= stackA(wordSize-8 downto 0);
+ stackA(6 downto 0) <= opcode(conv_integer(pc(byteBits-1 downto 0)))(6 downto 0);
+ else
+ out_mem_req <= '1';
+ mem_we <= '1';
+ mem_addr <= incSp;
+ mem_write <= stackB;
+ stackB <= stackA;
+ sp <= decSp;
+ for i in wordSize-1 downto 7 loop
+ stackA(i) <= opcode(conv_integer(pc(byteBits-1 downto 0)))(6);
+ end loop;
+ stackA(6 downto 0) <= opcode(conv_integer(pc(byteBits-1 downto 0)))(6 downto 0);
+ end if;
+ else
+ insn <= insn;
+ end if;
+ when State_StoreSP =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+ state <= State_StoreSP2;
+
+ out_mem_req <= '1';
+ mem_we <= '1';
+ mem_addr <= sp+spOffset;
+ mem_write <= stackA;
+ stackA <= stackB;
+ sp <= incSp;
+ else
+ insn <= insn;
+ end if;
+
+
+ when State_LoadSP =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+ state <= State_LoadSP2;
+
+ sp <= decSp;
+ out_mem_req <= '1';
+ mem_we <= '1';
+ mem_addr <= incSp;
+ mem_write <= stackB;
+ else
+ insn <= insn;
+ end if;
+ when State_Emulate =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+ sp <= decSp;
+ out_mem_req <= '1';
+ mem_we <= '1';
+ mem_addr <= incSp;
+ mem_write <= stackB;
+ stackA <= (others => DontCareValue);
+ stackA(maxAddrBitIncIO downto 0) <= pc + 1;
+ stackB <= stackA;
+
+ -- The emulate address is:
+ -- 98 7654 3210
+ -- 0000 00aa aaa0 0000
+ pc <= (others => '0');
+ pc(9 downto 5) <= opcode(conv_integer(pc(byteBits-1 downto 0)))(4 downto 0);
+ state <= State_Fetch;
+ else
+ insn <= insn;
+ end if;
+ when State_Callpcrel =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+ stackA <= (others => DontCareValue);
+ stackA(maxAddrBitIncIO downto 0) <= pc + 1;
+
+ pc <= pc + stackA(maxAddrBitIncIO downto 0);
+ state <= State_Fetch;
+ else
+ insn <= insn;
+ end if;
+ when State_Call =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+ stackA <= (others => DontCareValue);
+ stackA(maxAddrBitIncIO downto 0) <= pc + 1;
+ pc <= stackA(maxAddrBitIncIO downto 0);
+ state <= State_Fetch;
+ else
+ insn <= insn;
+ end if;
+ when State_AddSP =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+ state <= State_AddSP2;
+
+ out_mem_req <= '1';
+ mem_addr <= sp+spOffset;
+ else
+ insn <= insn;
+ end if;
+ when State_PushSP =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+ pc <= pc + 1;
+
+ sp <= decSp;
+ stackA <= (others => '0');
+ stackA(maxAddrBitIncIO downto minAddrBit) <= sp;
+ stackB <= stackA;
+ out_mem_req <= '1';
+ mem_we <= '1';
+ mem_addr <= incSp;
+ mem_write <= stackB;
+ else
+ insn <= insn;
+ end if;
+ when State_PopPC =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+ pc <= stackA(maxAddrBitIncIO downto 0);
+ sp <= incSp;
+
+ out_mem_req <= '1';
+ mem_we <= '1';
+ mem_addr <= incSp;
+ mem_write <= stackB;
+ state <= State_Resync;
+ else
+ insn <= insn;
+ end if;
+ when State_PopPCRel =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+ pc <= stackA(maxAddrBitIncIO downto 0) + pc;
+ sp <= incSp;
+
+ out_mem_req <= '1';
+ mem_we <= '1';
+ mem_addr <= incSp;
+ mem_write <= stackB;
+ state <= State_Resync;
+ else
+ insn <= insn;
+ end if;
+ when State_Add =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+ stackA <= stackA + stackB;
+
+ out_mem_req <= '1';
+ mem_addr <= incIncSp;
+ sp <= incSp;
+ state <= State_Popped;
+ else
+ insn <= insn;
+ end if;
+ when State_Sub =>
+ begin_inst <= '1';
+ idim_flag <= '0';
+ binaryOpResult <= stackB - stackA;
+ state <= State_BinaryOpResult;
+ when State_Pop =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+ mem_addr <= incIncSp;
+ out_mem_req <= '1';
+ sp <= incSp;
+ stackA <= stackB;
+ state <= State_Popped;
+ else
+ insn <= insn;
+ end if;
+ when State_PopDown =>
+ if mem_busy='0' then
+ -- PopDown leaves top of stack unchanged
+ begin_inst <= '1';
+ idim_flag <= '0';
+ mem_addr <= incIncSp;
+ out_mem_req <= '1';
+ sp <= incSp;
+ state <= State_Popped;
+ else
+ insn <= insn;
+ end if;
+ when State_Or =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+ stackA <= stackA or stackB;
+ out_mem_req <= '1';
+ mem_addr <= incIncSp;
+ sp <= incSp;
+ state <= State_Popped;
+ else
+ insn <= insn;
+ end if;
+ when State_And =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+
+ stackA <= stackA and stackB;
+ out_mem_req <= '1';
+ mem_addr <= incIncSp;
+ sp <= incSp;
+ state <= State_Popped;
+ else
+ insn <= insn;
+ end if;
+ when State_Eq =>
+ begin_inst <= '1';
+ idim_flag <= '0';
+
+ binaryOpResult <= (others => '0');
+ if (stackA=stackB) then
+ binaryOpResult(0) <= '1';
+ end if;
+ state <= State_BinaryOpResult;
+ when State_Ulessthan =>
+ begin_inst <= '1';
+ idim_flag <= '0';
+
+ binaryOpResult <= (others => '0');
+ if (stackA<stackB) then
+ binaryOpResult(0) <= '1';
+ end if;
+ state <= State_BinaryOpResult;
+ when State_Ulessthanorequal =>
+ begin_inst <= '1';
+ idim_flag <= '0';
+
+ binaryOpResult <= (others => '0');
+ if (stackA<=stackB) then
+ binaryOpResult(0) <= '1';
+ end if;
+ state <= State_BinaryOpResult;
+ when State_Lessthan =>
+ begin_inst <= '1';
+ idim_flag <= '0';
+
+ binaryOpResult <= (others => '0');
+ if (signed(stackA)<signed(stackB)) then
+ binaryOpResult(0) <= '1';
+ end if;
+ state <= State_BinaryOpResult;
+ when State_Lessthanorequal =>
+ begin_inst <= '1';
+ idim_flag <= '0';
+
+ binaryOpResult <= (others => '0');
+ if (signed(stackA)<=signed(stackB)) then
+ binaryOpResult(0) <= '1';
+ end if;
+ state <= State_BinaryOpResult;
+ when State_Load =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+ state <= State_Load2;
+
+ mem_addr <= stackA(maxAddrBitIncIO downto minAddrBit);
+ out_mem_req <= '1';
+ else
+ insn <= insn;
+ end if;
+
+ when State_Dup =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+ pc <= pc + 1;
+
+ sp <= decSp;
+ stackB <= stackA;
+ mem_write <= stackB;
+ mem_addr <= incSp;
+ out_mem_req <= '1';
+ mem_we <= '1';
+ else
+ insn <= insn;
+ end if;
+ when State_DupStackB =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+ pc <= pc + 1;
+
+ sp <= decSp;
+ stackA <= stackB;
+ stackB <= stackA;
+ mem_write <= stackB;
+ mem_addr <= incSp;
+ out_mem_req <= '1';
+ mem_we <= '1';
+ else
+ insn <= insn;
+ end if;
+ when State_Store =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+ pc <= pc + 1;
+ mem_addr <= stackA(maxAddrBitIncIO downto minAddrBit);
+ mem_write <= stackB;
+ out_mem_req <= '1';
+ mem_we <= '1';
+ sp <= incIncSp;
+ state <= State_Resync;
+ else
+ insn <= insn;
+ end if;
+ when State_PopSP =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+ pc <= pc + 1;
+
+ mem_write <= stackB;
+ mem_addr <= incSp;
+ out_mem_req <= '1';
+ mem_we <= '1';
+ sp <= stackA(maxAddrBitIncIO downto minAddrBit);
+ state <= State_Resync;
+ else
+ insn <= insn;
+ end if;
+ when State_Nop =>
+ begin_inst <= '1';
+ idim_flag <= '0';
+ pc <= pc + 1;
+ when State_Not =>
+ begin_inst <= '1';
+ idim_flag <= '0';
+ pc <= pc + 1;
+
+ stackA <= not stackA;
+ when State_Flip =>
+ begin_inst <= '1';
+ idim_flag <= '0';
+ pc <= pc + 1;
+
+ for i in 0 to wordSize-1 loop
+ stackA(i) <= stackA(wordSize-1-i);
+ end loop;
+ when State_AddTop =>
+ begin_inst <= '1';
+ idim_flag <= '0';
+ pc <= pc + 1;
+
+ stackA <= stackA + stackB;
+ when State_Shift =>
+ begin_inst <= '1';
+ idim_flag <= '0';
+ pc <= pc + 1;
+
+ stackA(wordSize-1 downto 1) <= stackA(wordSize-2 downto 0);
+ stackA(0) <= '0';
+ when State_Pushspadd =>
+ begin_inst <= '1';
+ idim_flag <= '0';
+ pc <= pc + 1;
+
+ stackA <= (others => '0');
+ stackA(maxAddrBitIncIO downto minAddrBit) <= stackA(maxAddrBitIncIO-minAddrBit downto 0)+sp;
+ when State_Neqbranch =>
+ -- branches are almost always taken as they form loops
+ begin_inst <= '1';
+ idim_flag <= '0';
+ sp <= incIncSp;
+ if (stackB/=0) then
+ pc <= stackA(maxAddrBitIncIO downto 0) + pc;
+ else
+ pc <= pc + 1;
+ end if;
+ -- need to fetch stack again.
+ state <= State_Resync;
+ when State_Mult =>
+ begin_inst <= '1';
+ idim_flag <= '0';
+
+ multA <= stackA;
+ multB <= stackB;
+ state <= State_Mult2;
+ when State_Break =>
+ report "Break instruction encountered" severity failure;
+ break <= '1';
+
+ when State_Loadb =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+ state <= State_Loadb2;
+
+ mem_addr <= stackA(maxAddrBitIncIO downto minAddrBit);
+ out_mem_req <= '1';
+ else
+ insn <= insn;
+ end if;
+ when State_Storeb =>
+ if mem_busy='0' then
+ begin_inst <= '1';
+ idim_flag <= '0';
+ state <= State_Storeb2;
+
+ mem_addr <= stackA(maxAddrBitIncIO downto minAddrBit);
+ out_mem_req <= '1';
+ else
+ insn <= insn;
+ end if;
+
+ when others =>
+-- sp <= (others => DontCareValue);
+ report "Illegal instruction" severity failure;
+ break <= '1';
+ end case;
+
+
+ when State_StoreSP2 =>
+ if mem_busy='0' then
+ mem_addr <= incSp;
+ out_mem_req <= '1';
+ state <= State_Popped;
+ end if;
+ when State_LoadSP2 =>
+ if mem_busy='0' then
+ state <= State_LoadSP3;
+ out_mem_req <= '1';
+ mem_addr <= sp+spOffset+1;
+ end if;
+ when State_LoadSP3 =>
+ if mem_busy='0' then
+ pc <= pc + 1;
+ state <= State_Execute;
+ stackB <= stackA;
+ stackA <= mem_read;
+ end if;
+ when State_AddSP2 =>
+ if mem_busy='0' then
+ pc <= pc + 1;
+ state <= State_Execute;
+ stackA <= stackA + mem_read;
+ end if;
+ when State_Load2 =>
+ if mem_busy='0' then
+ stackA <= mem_read;
+ pc <= pc + 1;
+ state <= State_Execute;
+ end if;
+ when State_Loadb2 =>
+ if mem_busy='0' then
+ stackA <= (others => '0');
+ stackA(7 downto 0) <= mem_read(((wordBytes-1-conv_integer(stackA(byteBits-1 downto 0)))*8+7) downto (wordBytes-1-conv_integer(stackA(byteBits-1 downto 0)))*8);
+ pc <= pc + 1;
+ state <= State_Execute;
+ end if;
+ when State_Storeb2 =>
+ if mem_busy='0' then
+ mem_addr <= stackA(maxAddrBitIncIO downto minAddrBit);
+ mem_write <= mem_read;
+ mem_write(((wordBytes-1-conv_integer(stackA(byteBits-1 downto 0)))*8+7) downto (wordBytes-1-conv_integer(stackA(byteBits-1 downto 0)))*8) <= stackB(7 downto 0) ;
+ out_mem_req <= '1';
+ mem_we <= '1';
+ pc <= pc + 1;
+ sp <= incIncSp;
+ state <= State_Resync;
+ end if;
+ when State_Fetch =>
+ if mem_busy='0' then
+ if interrupt='1' and inInterrupt='0' and idim_flag='0' then
+ -- We got an interrupt
+ inInterrupt <= '1';
+
+ sp <= decSp;
+ out_mem_req <= '1';
+ mem_we <= '1';
+ mem_addr <= incSp;
+ mem_write <= stackB;
+ stackA <= (others => DontCareValue);
+ stackA(maxAddrBitIncIO downto 0) <= pc;
+ stackB <= stackA;
+
+ pc <= conv_std_logic_vector(32, maxAddrBitIncIo+1); -- interrupt address
+
+ report "ZPU jumped to interrupt!" severity note;
+ else
+ mem_addr <= pc(maxAddrBitIncIO downto minAddrBit);
+ out_mem_req <= '1';
+ state <= State_Decode;
+ end if;
+ end if;
+ when State_Mult2 =>
+ state <= State_Mult3;
+ when State_Mult3 =>
+ state <= State_Mult4;
+ when State_Mult4 =>
+ state <= State_Mult5;
+ when State_Mult5 =>
+ stackA <= multResult3;
+ state <= State_Mult6;
+ when State_Mult6 =>
+ if mem_busy='0' then
+ out_mem_req <= '1';
+ mem_addr <= incIncSp;
+ sp <= incSp;
+ state <= State_Popped;
+ end if;
+ when State_BinaryOpResult =>
+ if mem_busy='0' then
+ -- NB!!!! we know that the memory isn't busy at this point!!!!
+ out_mem_req <= '1';
+ mem_addr <= incIncSp;
+ sp <= incSp;
+ stackA <= binaryOpResult;
+ state <= State_Popped;
+ end if;
+ when State_Popped =>
+ if mem_busy='0' then
+ pc <= pc + 1;
+ stackB <= mem_read;
+ state <= State_Execute;
+ end if;
+ when others =>
+-- sp <= (others => DontCareValue);
+ report "Illegal state" severity failure;
+ break <= '1';
+ end case;
+ end if;
+ end process;
+
+
+
+end behave;
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