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- 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
This commit is contained in:
jens
2009-03-16 11:31:51 +00:00
parent e465dc860b
commit 81c8bf1897
1 changed files with 356 additions and 324 deletions
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lib/CPUs/MIPS/src/core/mips_instr.vhd
+116 -84
View File
@@ -43,12 +43,7 @@ package mips_instr is
function extract_bimm18(instr, pc : word_t) return word_t; function extract_bimm18(instr, pc : word_t) return word_t;
function decode_op(instr : word_t) return op_t; function decode_op(instr : word_t) return op_t;
function ctrl_lines_default return ctrl_lines_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; end mips_instr;
@@ -153,12 +148,14 @@ package body mips_instr is
variable opc : natural range 0 to 63; variable opc : natural range 0 to 63;
variable func : natural range 0 to 63; variable func : natural range 0 to 63;
variable rt : natural range 0 to 31; variable rt : natural range 0 to 31;
variable rs : natural range 0 to 31;
begin begin
opc := to_integer(extract_opc(instr)); opc := to_integer(extract_opc(instr));
func := to_integer(extract_func(instr)); func := to_integer(extract_func(instr));
rt := to_integer(extract_rt(instr)); rt := to_integer(extract_rt(instr));
rs := to_integer(extract_rs(instr));
result := op_sll; result := op_sll;
@@ -317,16 +314,100 @@ package body mips_instr is
result := op_lui; result := op_lui;
when 16 => 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 => 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 => 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 => 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 => when 32 =>
result := op_lb; result := op_lb;
@@ -364,6 +445,9 @@ package body mips_instr is
when 46 => when 46 =>
result := op_swr; result := op_swr;
when 48 =>
result := op_lwc0; -- illegal
when 49 => when 49 =>
result := op_lwc1; result := op_lwc1;
@@ -373,6 +457,9 @@ package body mips_instr is
when 51 => when 51 =>
result := op_lwc3; result := op_lwc3;
when 56 =>
result := op_swc0; -- illegal
when 57 => when 57 =>
result := op_swc1; result := op_swc1;
@@ -436,16 +523,24 @@ package body mips_instr is
end ctrl_lines_default; 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 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 begin
result := ctrl_lines_default; 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 => when 32 =>
@@ -653,32 +748,9 @@ package body mips_instr is
end case; end case;
return result; -- REGIMM
when 1 =>
end special_ctrl_lines; case rt is
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 op_bgez =>
when 1 => when 1 =>
@@ -715,32 +787,9 @@ package body mips_instr is
end case; 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 op_addi =>
when 8 => when 8 =>
@@ -793,10 +842,6 @@ package body mips_instr is
result.bc_src := bc_eq_ne; result.bc_src := bc_eq_ne;
result.bc_not := '1'; result.bc_not := '1';
-- when op_cop =>
when 16 | 17 | 18 | 19 =>
result.cop_instr_en := '1';
-- when op_j => -- when op_j =>
when 2 => when 2 =>
result.jump := '1'; result.jump := '1';
@@ -977,19 +1022,6 @@ package body mips_instr is
end opcode_ctrl_lines; 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; end mips_instr;
-------------------------------------------------------------------------- --------------------------------------------------------------------------