- reworked exception stuff

- removed int-port (it's now in cop)

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git-svn-id: http://moon:8086/svn/vhdl/trunk@425 cc03376c-175c-47c8-b038-4cd826a8556b

lib/CPUs/MIPS/src/core/mips_pipeline.vhd

@@ -34,7 +34,6 @@ entity pipeline is
 		rst			: in  STD_LOGIC;
 		clk			: in  STD_LOGIC;
 		ce			: in  STD_LOGIC;
-		int			: in  unsigned(5 downto 0);
 		imem_err	: in  STD_LOGIC;
 		imem_rdy	: in  STD_LOGIC;
 		imem_en		: out STD_LOGIC;
@@ -171,6 +170,8 @@ architecture Behavioral of pipeline is
 	signal bcu_flags		: bcu_flags_t;
 	signal vaddr			: word_t;
 	signal dmem_src			: word_t;
+	signal stage_rst		: unsigned(3 downto 0);
+	signal pipe_rst			: STD_LOGIC;
 	
 	attribute ram_style : string;
 	
@@ -187,13 +188,13 @@ begin
 	cpu_run					<= ce;
 	
 	-- Stall Detection Unit ---------------------------------------------------
-	sdu.ID_nop				<= sdu.imem_dep or c0_ctrl_in.exc_pending or EX_stage.exc or MEM_stage.exc;
+	sdu.ID_nop				<= sdu.imem_dep or c0_ctrl_in.exc_pending or ID_stage.exc or EX_stage.exc or MEM_stage.exc;
 	sdu.EX_nop				<= sdu.mul_dep or ID_stage.nop or ID_stage.exc;
 	sdu.MEM_nop				<= EX_stage.nop or EX_stage.exc;
 	sdu.WB_nop				<= sdu.dmem_dep or MEM_stage.nop;
 
 	sdu.stall_all			<= sdu.dmem_dep;
-	sdu.ID_stall			<= sdu.stall_all or sdu.imem_dep or sdu.mul_dep or ID_stage.exc;
+	sdu.ID_stall			<= sdu.stall_all or sdu.imem_dep or sdu.mul_dep or c0_ctrl_in.exc_exit;
 	sdu.EX_stall			<= sdu.stall_all;
 	sdu.MEM_stall			<= sdu.stall_all;
 	sdu.WB_stall			<= '0';
@@ -210,10 +211,12 @@ begin
 	c0_ctrl_out.bd_wb		<= WB_stage.bd;
 	c0_ctrl_out.epc_mem		<= MEM_stage.pcn;
 	c0_ctrl_out.epc_wb		<= MEM_stage.epc;
-	c0_ctrl_out.imem_addr	<= pc.nxt;
+	c0_ctrl_out.imem_addr	<= EX_stage.epc;
 	c0_ctrl_out.dmem_addr	<= MEM_stage.va;
 	c0_ctrl_out.sdu			<= sdu;
-	c0_ctrl_out.events		<= MEM_stage.events;
+	c0_ctrl_out.events		<= WB_stage.events;
+	c0_ctrl_out.exc_req		<= MEM_stage.exc;
+	c0_ctrl_out.exc_ack		<= WB_stage.exc;
 	cop_ir					<= ID_stage.IR;
 	cop_ir_en				<= ID_stage.ctrl.cop_instr_en;
 	cop_dout				<= MEM_stage.data;
@@ -242,10 +245,24 @@ inst_muldiv: muldiv
 --------------------------------------------------------------------------
 	imem_addr		<= pc.curr;
 
+	pipe_rst		<= stage_rst(0);
+	
+proc_stage_reset:
+	process(clk_1)
+	begin
+		if rising_edge(clk_1) then
+			if rst = '1' then
+				stage_rst <= (others => '1');
+			else
+				stage_rst <= stage_rst(stage_rst'left-1 downto 0) & '0';
+			end if;	
+		end if;	
+	end process;
+
 proc_stage_pc:
 	process(pc, c0_ctrl_in)
 	begin
-		if pc.is_branch and c0_ctrl_in.exc_pending = '0' then
+		if pc.is_branch then
 			pc.curr	<= pc.pc_branch after 2 ns;
 		else
 			pc.curr	<= pc.nxt after 2 ns;
@@ -266,17 +283,15 @@ proc_stage_pc_next:
 	process(clk_1)
 	begin
 		if rising_edge(clk_1) then
-			c0_ctrl_out.exc_left		<= '0';
+			if pipe_rst = '1' then
-			if rst = '1' then
 				pc.nxt	<= RESET_VECTOR;
 				pc.last	<= RESET_VECTOR;
 				branch_ce	<= '1';
 			else
-				branch_ce	<= '0';
+				branch_ce	<= c0_ctrl_in.exc_pending;
-				if c0_ctrl_in.exc_commit = '1' then
+				if c0_ctrl_in.exc_inject = '1' then
 					pc.nxt	<= c0_ctrl_in.exc_vec;
 				elsif sdu.ID_stall = '0' then
-					c0_ctrl_out.exc_left		<= c0_ctrl_in.exc_exit;
 					branch_ce	<= '1';
 					pc.last	<= pc.curr;
 					if ID_stage.ctrl.jump = '1' then
@@ -342,8 +357,8 @@ proc_ID_except:
 	process(ID_stage, c0_ctrl_in, pc)
 	begin	
 		ID_stage.events					<= events_clr;
-		ID_stage.events.inst_load_err	<= pc.nxt(1) or pc.nxt(0);
+		ID_stage.events.inst_load_err	<= not c0_ctrl_in.exc_pending and (pc.nxt(1) or pc.nxt(0));
-		ID_stage.events.inst_priv_addr	<= pc.nxt(word_t'left) and c0_ctrl_in.user_mode;
+		ID_stage.events.inst_priv_addr	<= not c0_ctrl_in.exc_pending and (pc.nxt(word_t'left) and c0_ctrl_in.user_mode);
 	end process;
 	
 proc_stage_hdu:
@@ -459,7 +474,7 @@ proc_stage_ID_EX_1:
 	process(clk_1)
 	begin
 		if rising_edge(clk_1) then
-			if rst = '1' then
+			if stage_rst(1) = '1' then
 				EX_stage.op						<= NOP;
 				EX_stage.IR						<= (others => '0');
 				EX_stage.ctrl					<= ctrl_lines_default;
@@ -477,13 +492,12 @@ proc_stage_ID_EX_1:
 				EX_stage.nop			<= sdu.EX_nop;
 				EX_stage.IR				<= ID_stage.IR;
 				EX_stage.pcn			<= ID_stage.pcn;
+				EX_stage.epc			<= ID_stage.epc;
 				if sdu.EX_nop = '1' then
 					EX_stage.op				<= NOP;
 					EX_stage.IR				<= (others => '0');
 					EX_stage.ctrl			<= ctrl_lines_default;
 					EX_stage.reg_write		<= '0';
-				else
-					EX_stage.epc			<= ID_stage.epc;
 				end if;
 			end if;	
 		end if;
@@ -518,7 +532,7 @@ proc_stage_EX_mem_except:
 	process(clk_1)
 	begin
 		if rising_edge(clk_1) then
-			if rst = '1' then
+			if pipe_rst = '1' then
 				dmem_en		<= '0';
 			elsif sdu.EX_stall = '0' then
 				EX_events_mem	<= events_clr;
@@ -715,7 +729,7 @@ proc_stage_MEM_n:
 	process(clk_1)
 	begin
 		if rising_edge(clk_1) then
-			if rst = '1' then
+			if stage_rst(2) = '1' then
 				MEM_stage.op		<= NOP;
 				MEM_stage.wreg_we	<= '0';
 				MEM_stage.ctrl		<= ctrl_lines_default;
@@ -726,7 +740,9 @@ proc_stage_MEM_n:
 				MEM_stage.op			<= EX_stage.op;
 				MEM_stage.wreg_we		<= EX_stage.wreg_we;
 				MEM_stage.ctrl			<= EX_stage.ctrl;
+				if EX_stage.ctrl.dmem_en = '1' then
 					MEM_stage.va			<= EX_stage.va;
+				end if;	
 				MEM_stage.pa_off		<= EX_stage.pa_off;
 				MEM_stage.reg_wptr		<= EX_stage.reg_wptr;
 				MEM_stage.nop			<= sdu.MEM_nop;
@@ -760,7 +776,7 @@ proc_stage_MEM_mux:
 		data	:= MEM_stage.ex_result;
 		be		:= load_be(MEM_stage.pa_off, MEM_stage.ctrl.align_left, MEM_stage.ctrl.byte_en_byp);
 		if MEM_stage.ctrl.reg_link = '1' then
-			data		:= MEM_stage.pcn + 4;
+			data		:= MEM_stage.epc + 8;
 		elsif MEM_stage.ctrl.dmem_en = '1' then
 			temp1		:= load_shift(dmem_din,  MEM_stage.pa_off, MEM_stage.ctrl.shift_offset, MEM_stage.ctrl.shift_byp);
 			temp2		:= load_sign_ext(temp1, MEM_stage.ctrl.sign_ext_byp, MEM_stage.ctrl.load_signed, MEM_stage.ctrl.word2_en, MEM_stage.ctrl.word4_en);
@@ -782,13 +798,13 @@ proc_stage_MEM_mux:
 	end process;
 
 proc_stage_MEM_except:
-	process(MEM_stage, int)
+	process(MEM_stage, c0_ctrl_in)
 	begin
 		MEM_stage.events				<= MEM_stage.events_in;
-		MEM_stage.events.Int			<= int;
+		MEM_stage.events.Int			<= c0_ctrl_in.int;
 	end process;
 
-	MEM_stage.exc	<= c0_ctrl_in.int or event_is_active(MEM_stage.events_in);
+	MEM_stage.exc	<= event_is_active(MEM_stage.events);
 
 --------------------------------------------------------------------------
 -- WB stage
@@ -797,22 +813,29 @@ proc_stage_WB_p:
 	process(clk_1)
 	begin
 		if rising_edge(clk_1) then
-			if rst = '1' then
+			if stage_rst(3) = '1' then
 				WB_stage.op				<= NOP;
 				WB_stage.wreg_we		<= '1';
 				WB_stage.reg_wptr		<= (others => '0');
 				WB_stage.data			<= (others => '0');
+				WB_stage.events			<= events_clr;
 			elsif sdu.WB_stall = '0' then
 				WB_stage.op				<= MEM_stage.op;
 				WB_stage.wreg_we		<= MEM_stage.wreg_we;
 				WB_stage.reg_wptr		<= MEM_stage.reg_wptr;
 				WB_stage.data			<= MEM_stage.data;
+				WB_stage.exc			<= '0';
+				if sdu.stall_all = '0' then
+					WB_stage.exc			<= MEM_stage.exc;
+					if MEM_stage.exc = '1' then
+						WB_stage.events			<= MEM_stage.events;
+					end if;	
+				end if;	
 				WB_stage.nop			<= sdu.WB_nop;
 				if sdu.WB_nop = '1' then
 					WB_stage.op				<= NOP;
 					WB_stage.wreg_we		<= '0';
 				else
-					WB_stage.epc			<= MEM_stage.epc;
 					WB_stage.bd				<= MEM_stage.ctrl.branch or MEM_stage.ctrl.jump or MEM_stage.ctrl.jump_long; -- Todo: works
 				end if;	
 			end if;