- simplified instruction decoder and removed genrom functions

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git-svn-id: http://moon:8086/svn/vhdl/trunk@394 cc03376c-175c-47c8-b038-4cd826a8556b

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

@@ -43,12 +43,7 @@ package mips_instr is
 	function extract_bimm18(instr, pc : word_t) return word_t;
 	function decode_op(instr : word_t) return op_t;
 	function ctrl_lines_default return ctrl_lines_t;
-	function special_ctrl_lines(func : func_t) return ctrl_lines_t;
+	function opcode_ctrl_lines(instr : word_t) return ctrl_lines_t;
-	function regimm_ctrl_lines(rt : reg_ptr_t) return ctrl_lines_t;
-	function opcode_ctrl_lines(opc : opcode_t) return ctrl_lines_t;
-	function gen_rom_opcode return rom_opcode_t;
-	function gen_rom_regimm return rom_regimm_t;
-	function gen_rom_special return rom_special_t;
 
 end mips_instr;
 
@@ -153,12 +148,14 @@ package body mips_instr is
 	variable opc : natural range 0 to 63;
 	variable func : natural range 0 to 63;
 	variable rt : natural range 0 to 31;
+	variable rs : natural range 0 to 31;
 	
 	begin
 		
 		opc		:= to_integer(extract_opc(instr));
 		func	:= to_integer(extract_func(instr));
 		rt		:= to_integer(extract_rt(instr));
+		rs		:= to_integer(extract_rs(instr));
 		
 		result := op_sll;
 		
@@ -317,16 +314,100 @@ package body mips_instr is
 			result	:= op_lui;
 
 		when 16 =>
-			result	:= op_cop0;
+			case rs is
+				when 0 =>
+					result	:= op_mfc0;
+				when 2 =>
+					result	:= op_cfc0;	-- illegal
+				when 4 =>
+					result	:= op_mtc0;
+				when 6 =>
+					result	:= op_ctc0;	-- illegal
+				when 8 =>
+					case rt is
+						when 0 =>
+							result := op_bcf0;	-- illegal
+						when 1 =>
+							result := op_bct0;	-- illegal
+			
+						when others => null; -- undef
+					end case;	
+							
+				when others => null; -- undef
+			
+			end case;
 
 		when 17 =>
-			result	:= op_cop1;
+			case rs is
+				when 0 =>
+					result	:= op_mfc1;
+				when 2 =>
+					result	:= op_cfc1;
+				when 4 =>
+					result	:= op_mtc1;
+				when 6 =>
+					result	:= op_ctc1;
+				when 8 =>
+					case rt is
+						when 0 =>
+							result := op_bcf1;
+						when 1 =>
+							result := op_bct1;
+			
+						when others => null; -- undef
+					end case;	
+							
+				when others => null; -- undef
+			
+			end case;
 
 		when 18 =>
-			result	:= op_cop2;
+			case rs is
+				when 0 =>
+					result	:= op_mfc2;
+				when 2 =>
+					result	:= op_cfc2;
+				when 4 =>
+					result	:= op_mtc2;
+				when 6 =>
+					result	:= op_ctc2;
+				when 8 =>
+					case rt is
+						when 0 =>
+							result := op_bcf2;
+						when 1 =>
+							result := op_bct2;
+			
+						when others => null; -- undef
+					end case;	
+							
+				when others => null; -- undef
+			
+			end case;
 
 		when 19 =>
-			result	:= op_cop3;
+			case rs is
+				when 0 =>
+					result	:= op_mfc3;
+				when 2 =>
+					result	:= op_cfc3;
+				when 4 =>
+					result	:= op_mtc3;
+				when 6 =>
+					result	:= op_ctc3;
+				when 8 =>
+					case rt is
+						when 0 =>
+							result := op_bcf3;
+						when 1 =>
+							result := op_bct3;
+			
+						when others => null; -- undef
+					end case;	
+							
+				when others => null; -- undef
+			
+			end case;
 
 		when 32 =>
 			result	:= op_lb;
@@ -364,6 +445,9 @@ package body mips_instr is
 		when 46 =>
 			result	:= op_swr;
 
+		when 48 =>
+			result	:= op_lwc0;	-- illegal
+			
 		when 49 =>
 			result	:= op_lwc1;
 			
@@ -373,6 +457,9 @@ package body mips_instr is
 		when 51 =>
 			result	:= op_lwc3;
 
+		when 56 =>
+			result	:= op_swc0;	-- illegal
+
 		when 57 =>
 			result	:= op_swc1;
 			
@@ -436,18 +523,26 @@ package body mips_instr is
 	
 	end ctrl_lines_default;
 
-
+	function opcode_ctrl_lines(instr : word_t) return ctrl_lines_t is
-	function special_ctrl_lines(func : func_t) return ctrl_lines_t is
 	variable result : ctrl_lines_t;
-	variable op : integer range 0 to 2**func_t'length-1;
+	variable opc	: integer range 0 to 2**opcode_t'length-1;
+	variable func	: integer range 0 to 2**func_t'length-1;
+	variable rt		: integer range 0 to 2**reg_ptr_t'length-1;
+	variable rs		: integer range 0 to 2**reg_ptr_t'length-1;
 	begin
 	
 		result	:= ctrl_lines_default;
+		opc		:= to_integer(extract_opc(instr));
+		func 	:= to_integer(extract_func(instr));
+		rt 		:= to_integer(extract_rt(instr));
+		rs 		:= to_integer(extract_rs(instr));
 
-		op	:= to_integer(func);
+		case opc is
-		case op is
+--		SPECIAL
+		when 0 =>	
+			case func is
 
---		when op_add  =>
+	--		when op_add  =>
 			when 32 =>
 				result.alu.outsel		:= alu_adder;
 				result.alu.add			:= '1';
@@ -456,7 +551,7 @@ package body mips_instr is
 				result.reg_write		:= '1';
 				result.alu_exc_en		:= '1';
 
---		when op_addu =>
+	--		when op_addu =>
 			when 33 =>
 				result.alu.outsel		:= alu_adder;
 				result.alu.add			:= '1';
@@ -464,94 +559,94 @@ package body mips_instr is
 				result.alu.op2_src		:= alu_src_reg;
 				result.reg_write		:= '1';
 
---		when op_and =>
+	--		when op_and =>
 			when 36 =>
 				result.alu.outsel		:= alu_and;
 				result.alu.op1_src		:= alu_src_reg;
 				result.alu.op2_src		:= alu_src_reg;
 				result.reg_write		:= '1';
 
---		when op_break =>
+	--		when op_break =>
 			when 13 =>
 				result.exc_break		:= '1';
 				result.except_en		:= '1';
 
---		when op_div =>
+	--		when op_div =>
 			when 26 =>
 				result.mul_access		:= '1';
 				result.mul_start		:= '1';
 				result.mul_s_un			:= '1';
 				result.mul_mul_divn		:= '0';
 
---		when op_divu =>
+	--		when op_divu =>
 			when 27 =>
 				result.mul_access		:= '1';
 				result.mul_start		:= '1';
 				result.mul_s_un			:= '0';
 				result.mul_mul_divn		:= '0';
 
---		when op_jalr =>
+	--		when op_jalr =>
 			when 9 =>
 				result.jump_long		:= '1';
 				result.wptr_srcsel		:= wptr_src_imm;
 				result.reg_write		:= '1';
 				result.reg_link			:= '1';
 
---		when op_jr =>
+	--		when op_jr =>
 			when 8 =>
 				result.jump_long		:= '1';
 
---		when op_mfhi =>
+	--		when op_mfhi =>
 			when 16 =>
 				result.reg_write		:= '1';
 				result.mul_access		:= '1';
 				result.mul_hilo_sel		:= '1';
 
---		when op_mflo =>
+	--		when op_mflo =>
 			when 18 =>
 				result.reg_write		:= '1';
 				result.mul_access		:= '1';
 				result.mul_hilo_sel		:= '0';
 
---		when op_mthi =>
+	--		when op_mthi =>
 			when 17 =>
 				result.mul_hilo_we		:= '1';
 				result.mul_hilo_sel		:= '1';
 
---		when op_mtlo =>
+	--		when op_mtlo =>
 			when 19 =>
 				result.mul_hilo_we		:= '1';
 				result.mul_hilo_sel		:= '0';
 
---		when op_mult =>
+	--		when op_mult =>
 			when 24 =>
 				result.mul_access		:= '1';
 				result.mul_start		:= '1';
 				result.mul_s_un			:= '1';
 				result.mul_mul_divn		:= '1';
 
---		when op_multu =>
+	--		when op_multu =>
 			when 25 =>
 				result.mul_access		:= '1';
 				result.mul_start		:= '1';
 				result.mul_s_un			:= '0';
 				result.mul_mul_divn		:= '1';
 
---		when op_or =>
+	--		when op_or =>
 			when 37 =>
 				result.alu.outsel		:= alu_or;
 				result.alu.op1_src		:= alu_src_reg;
 				result.alu.op2_src		:= alu_src_reg;
 				result.reg_write		:= '1';
 
---		when op_nor =>
+	--		when op_nor =>
 			when 39 =>
 				result.alu.outsel		:= alu_nor;
 				result.alu.op1_src		:= alu_src_reg;
 				result.alu.op2_src		:= alu_src_reg;
 				result.reg_write		:= '1';
 
---		when op_sll =>
+	--		when op_sll =>
 			when 0 =>
 				result.alu.op2_src		:= alu_src_reg;
 				result.alu.outsel		:= alu_shift2;
@@ -559,7 +654,7 @@ package body mips_instr is
 				result.shamt2_srcsel	:= sa_src_imm;
 				result.reg_write		:= '1';
 
---		when op_sllv =>
+	--		when op_sllv =>
 			when 4 =>
 				result.alu.op2_src		:= alu_src_reg;
 				result.alu.outsel		:= alu_shift2;
@@ -567,7 +662,7 @@ package body mips_instr is
 				result.shamt2_srcsel	:= sa_src_reg;
 				result.reg_write		:= '1';
 
---		when op_slt =>
+	--		when op_slt =>
 			when 42 =>
 				result.alu.outsel		:= alu_lts;
 				result.alu.add			:= '0';
@@ -575,7 +670,7 @@ package body mips_instr is
 				result.alu.op2_src		:= alu_src_reg;
 				result.reg_write		:= '1';
 
---		when op_sltu =>
+	--		when op_sltu =>
 			when 43 =>
 				result.alu.outsel		:= alu_ltu;
 				result.alu.add			:= '0';
@@ -583,7 +678,7 @@ package body mips_instr is
 				result.alu.op2_src		:= alu_src_reg;
 				result.reg_write		:= '1';
 
---		when op_sra =>
+	--		when op_sra =>
 			when 3 =>
 				result.alu.op2_src		:= alu_src_reg;
 				result.alu.outsel		:= alu_shift2;
@@ -592,7 +687,7 @@ package body mips_instr is
 				result.shamt2_srcsel	:= sa_src_imm;
 				result.reg_write		:= '1';
 
---		when op_srav =>
+	--		when op_srav =>
 			when 7 =>
 				result.alu.op2_src		:= alu_src_reg;
 				result.alu.outsel		:= alu_shift2;
@@ -601,7 +696,7 @@ package body mips_instr is
 				result.shamt2_srcsel	:= sa_src_reg;
 				result.reg_write		:= '1';
 
---		when op_srl =>
+	--		when op_srl =>
 			when 2 =>
 				result.alu.op2_src		:= alu_src_reg;
 				result.alu.outsel		:= alu_shift2;
@@ -610,7 +705,7 @@ package body mips_instr is
 				result.shamt2_srcsel	:= sa_src_imm;
 				result.reg_write		:= '1';
 
---		when op_srlv =>
+	--		when op_srlv =>
 			when 6 =>
 				result.alu.op2_src		:= alu_src_reg;
 				result.alu.outsel		:= alu_shift2;
@@ -619,7 +714,7 @@ package body mips_instr is
 				result.shamt2_srcsel	:= sa_src_reg;
 				result.reg_write		:= '1';
 
---		when op_sub =>
+	--		when op_sub =>
 			when 34 =>
 				result.alu.outsel		:= alu_adder;
 				result.alu.add			:= '0';
@@ -628,7 +723,7 @@ package body mips_instr is
 				result.reg_write		:= '1';
 				result.alu_exc_en		:= '1';
 
---		when op_subu =>
+	--		when op_subu =>
 			when 35 =>
 				result.alu.outsel		:= alu_adder;
 				result.alu.add			:= '0';
@@ -636,12 +731,12 @@ package body mips_instr is
 				result.alu.op2_src		:= alu_src_reg;
 				result.reg_write		:= '1';
 
---		when op_syscall =>
+	--		when op_syscall =>
 			when 12 =>
 				result.exc_syscall		:= '1';
 				result.except_en		:= '1';
 
---		when op_xor =>
+	--		when op_xor =>
 			when 38 =>
 				result.alu.outsel		:= alu_xor;
 				result.alu.op1_src		:= alu_src_reg;
@@ -653,40 +748,17 @@ package body mips_instr is
 
 			end case;
 
-		return result;
+--		REGIMM
+		when 1 =>	
+			case rt is
 
-	end special_ctrl_lines;
+	--		when op_bgez =>
-	
-	function gen_rom_special return rom_special_t is
-	variable result : rom_special_t; 
-	variable func : func_t;
-	begin
-		
-		for i in 0 to 2**func_t'length-1 loop
-			func := to_unsigned(i, func_t'length);
-			result(i) := special_ctrl_lines(func);
-		end loop;
-
-		return result;
-	end gen_rom_special;
-
-	function regimm_ctrl_lines(rt : reg_ptr_t) return ctrl_lines_t is
-	variable result : ctrl_lines_t;
-	variable op : integer range 0 to 2**reg_ptr_t'length-1;
-	begin
-	
-		result := ctrl_lines_default;
-		
-		op	:= to_integer(rt);
-		case op is
-
---		when op_bgez =>
 			when 1 =>
 				result.branch			:= '1';
 				result.bc_src			:= bc_ltz_gez;
 				result.bc_not			:= '1';
 
---		when op_bgezal =>
+	--		when op_bgezal =>
 			when 17 =>
 				result.branch			:= '1';
 				result.bc_src			:= bc_ltz_gez;
@@ -695,13 +767,13 @@ package body mips_instr is
 				result.reg_write		:= '1';
 				result.reg_link			:= '1';
 
---		when op_bltz =>
+	--		when op_bltz =>
 			when 0 =>
 				result.branch			:= '1';
 				result.bc_src			:= bc_ltz_gez;
 				result.bc_not			:= '0';
 
---		when op_bltzal =>
+	--		when op_bltzal =>
 			when 16 =>
 				result.branch			:= '1';
 				result.bc_src			:= bc_ltz_gez;
@@ -715,32 +787,9 @@ package body mips_instr is
 
 			end case;
 
-		return result;
+--		when COPz =>
-	
+		when 16 | 17 | 18 | 19 =>			
-	end regimm_ctrl_lines;
+			result.cop_instr_en		:= '1';
-
-	function gen_rom_regimm return rom_regimm_t is
-	variable result : rom_regimm_t; 
-	variable rt : reg_ptr_t;
-	begin
-		
-		for i in 0 to 2**reg_ptr_t'length-1 loop
-			rt := to_unsigned(i, reg_ptr_t'length);
-			result(i) := regimm_ctrl_lines(rt);
-		end loop;
-
-		return result;
-	end gen_rom_regimm;
-
-	function opcode_ctrl_lines(opc : opcode_t) return ctrl_lines_t is
-	variable result : ctrl_lines_t;
-	variable op : integer range 0 to 2**opcode_t'length-1;
-	begin
-	
-		result := ctrl_lines_default;
-
-		op	:= to_integer(opc);
-		case op is
 			
 --		when op_addi =>
 		when 8 =>
@@ -793,10 +842,6 @@ package body mips_instr is
 			result.bc_src			:= bc_eq_ne;
 			result.bc_not			:= '1';
 
---		when op_cop =>			
-		when 16 | 17 | 18 | 19 =>			
-			result.cop_instr_en		:= '1';
-			
 --		when op_j =>
 		when 2 =>
 			result.jump				:= '1';
@@ -977,19 +1022,6 @@ package body mips_instr is
 	
 	end opcode_ctrl_lines;
 
-	function gen_rom_opcode return rom_opcode_t is
-	variable result : rom_opcode_t; 
-	variable opc : opcode_t;
-	begin
-		
-		for i in 0 to 2**opcode_t'length-1 loop
-			opc := to_unsigned(i, opcode_t'length);
-			result(i) := opcode_ctrl_lines(opc);
-		end loop;
-
-		return result;
-	end gen_rom_opcode;
-
 end mips_instr;
 
 --------------------------------------------------------------------------