diff options
| author | Mike Stirling <opensource@mikestirling.co.uk> | 2011-07-12 20:52:34 +0100 |
|---|---|---|
| committer | Mike Stirling <opensource@mikestirling.co.uk> | 2011-07-12 20:52:34 +0100 |
| commit | 3975fdfe4275347dab666e43dbfdaebe80c58ff8 (patch) | |
| tree | 5558fbfb78e6196545fd2fe47465a714d2461e73 /T65 | |
| download | fpga-bbc-3975fdfe4275347dab666e43dbfdaebe80c58ff8.tar.gz fpga-bbc-3975fdfe4275347dab666e43dbfdaebe80c58ff8.tar.bz2 fpga-bbc-3975fdfe4275347dab666e43dbfdaebe80c58ff8.zip | |
Initial commit. Some modules imported from experimental 6502 platform. Project added for Quartus 9.1
Diffstat (limited to 'T65')
| -rw-r--r-- | T65/T65.vhd | 551 | ||||
| -rw-r--r-- | T65/T65_ALU.vhd | 260 | ||||
| -rw-r--r-- | T65/T65_MCode.vhd | 1052 | ||||
| -rw-r--r-- | T65/T65_Pack.vhd | 117 |
4 files changed, 1980 insertions, 0 deletions
diff --git a/T65/T65.vhd b/T65/T65.vhd new file mode 100644 index 0000000..f02a5b6 --- /dev/null +++ b/T65/T65.vhd @@ -0,0 +1,551 @@ +-- ****
+-- T65(b) core. In an effort to merge and maintain bug fixes ....
+--
+--
+-- Ver 301 more merging
+-- Ver 300 Bugfixes by ehenciak added, started tidyup *bust*
+-- MikeJ March 2005
+-- Latest version from www.fpgaarcade.com (original www.opencores.org)
+--
+-- ****
+--
+-- 65xx compatible microprocessor core
+--
+-- Version : 0246
+--
+-- Copyright (c) 2002 Daniel Wallner (jesus@opencores.org)
+--
+-- All rights reserved
+--
+-- Redistribution and use in source and synthezised forms, with or without
+-- modification, are permitted provided that the following conditions are met:
+--
+-- Redistributions of source code must retain the above copyright notice,
+-- this list of conditions and the following disclaimer.
+--
+-- Redistributions in synthesized form must reproduce the above copyright
+-- notice, this list of conditions and the following disclaimer in the
+-- documentation and/or other materials provided with the distribution.
+--
+-- Neither the name of the author nor the names of other contributors may
+-- be used to endorse or promote products derived from this software without
+-- specific prior written permission.
+--
+-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+-- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+-- THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+-- PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE
+-- LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+-- CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+-- SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+-- INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+-- CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+-- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+-- POSSIBILITY OF SUCH DAMAGE.
+--
+-- Please report bugs to the author, but before you do so, please
+-- make sure that this is not a derivative work and that
+-- you have the latest version of this file.
+--
+-- The latest version of this file can be found at:
+-- http://www.opencores.org/cvsweb.shtml/t65/
+--
+-- Limitations :
+--
+-- 65C02 and 65C816 modes are incomplete
+-- Undocumented instructions are not supported
+-- Some interface signals behaves incorrect
+--
+-- File history :
+--
+-- 0246 : First release
+--
+
+library IEEE;
+ use IEEE.std_logic_1164.all;
+ use IEEE.numeric_std.all;
+ use work.T65_Pack.all;
+
+-- ehenciak 2-23-2005 : Added the enable signal so that one doesn't have to use
+-- the ready signal to limit the CPU.
+entity T65 is
+ port(
+ Mode : in std_logic_vector(1 downto 0); -- "00" => 6502, "01" => 65C02, "10" => 65C816
+ Res_n : in std_logic;
+ Enable : in std_logic;
+ Clk : in std_logic;
+ Rdy : in std_logic;
+ Abort_n : in std_logic;
+ IRQ_n : in std_logic;
+ NMI_n : in std_logic;
+ SO_n : in std_logic;
+ R_W_n : out std_logic;
+ Sync : out std_logic;
+ EF : out std_logic;
+ MF : out std_logic;
+ XF : out std_logic;
+ ML_n : out std_logic;
+ VP_n : out std_logic;
+ VDA : out std_logic;
+ VPA : out std_logic;
+ A : out std_logic_vector(23 downto 0);
+ DI : in std_logic_vector(7 downto 0);
+ DO : out std_logic_vector(7 downto 0)
+ );
+end T65;
+
+architecture rtl of T65 is
+
+ -- Registers
+ signal ABC, X, Y, D : std_logic_vector(15 downto 0);
+ signal P, AD, DL : std_logic_vector(7 downto 0) := x"00";
+ signal BAH : std_logic_vector(7 downto 0);
+ signal BAL : std_logic_vector(8 downto 0);
+ signal PBR : std_logic_vector(7 downto 0);
+ signal DBR : std_logic_vector(7 downto 0);
+ signal PC : unsigned(15 downto 0);
+ signal S : unsigned(15 downto 0);
+ signal EF_i : std_logic;
+ signal MF_i : std_logic;
+ signal XF_i : std_logic;
+
+ signal IR : std_logic_vector(7 downto 0);
+ signal MCycle : std_logic_vector(2 downto 0);
+
+ signal Mode_r : std_logic_vector(1 downto 0);
+ signal ALU_Op_r : std_logic_vector(3 downto 0);
+ signal Write_Data_r : std_logic_vector(2 downto 0);
+ signal Set_Addr_To_r : std_logic_vector(1 downto 0);
+ signal PCAdder : unsigned(8 downto 0);
+
+ signal RstCycle : std_logic;
+ signal IRQCycle : std_logic;
+ signal NMICycle : std_logic;
+
+ signal B_o : std_logic;
+ signal SO_n_o : std_logic;
+ signal IRQ_n_o : std_logic;
+ signal NMI_n_o : std_logic;
+ signal NMIAct : std_logic;
+
+ signal Break : std_logic;
+
+ -- ALU signals
+ signal BusA : std_logic_vector(7 downto 0);
+ signal BusA_r : std_logic_vector(7 downto 0);
+ signal BusB : std_logic_vector(7 downto 0);
+ signal ALU_Q : std_logic_vector(7 downto 0);
+ signal P_Out : std_logic_vector(7 downto 0);
+
+ -- Micro code outputs
+ signal LCycle : std_logic_vector(2 downto 0);
+ signal ALU_Op : std_logic_vector(3 downto 0);
+ signal Set_BusA_To : std_logic_vector(2 downto 0);
+ signal Set_Addr_To : std_logic_vector(1 downto 0);
+ signal Write_Data : std_logic_vector(2 downto 0);
+ signal Jump : std_logic_vector(1 downto 0);
+ signal BAAdd : std_logic_vector(1 downto 0);
+ signal BreakAtNA : std_logic;
+ signal ADAdd : std_logic;
+ signal AddY : std_logic;
+ signal PCAdd : std_logic;
+ signal Inc_S : std_logic;
+ signal Dec_S : std_logic;
+ signal LDA : std_logic;
+ signal LDP : std_logic;
+ signal LDX : std_logic;
+ signal LDY : std_logic;
+ signal LDS : std_logic;
+ signal LDDI : std_logic;
+ signal LDALU : std_logic;
+ signal LDAD : std_logic;
+ signal LDBAL : std_logic;
+ signal LDBAH : std_logic;
+ signal SaveP : std_logic;
+ signal Write : std_logic;
+
+ signal really_rdy : std_logic;
+ signal R_W_n_i : std_logic;
+
+begin
+ -- ehenciak : gate Rdy with read/write to make an "OK, it's
+ -- really OK to stop the processor now if Rdy is
+ -- deasserted" signal
+ really_rdy <= Rdy or not(R_W_n_i);
+
+ -- ehenciak : Drive R_W_n_i off chip.
+ R_W_n <= R_W_n_i;
+
+ Sync <= '1' when MCycle = "000" else '0';
+ EF <= EF_i;
+ MF <= MF_i;
+ XF <= XF_i;
+ ML_n <= '0' when IR(7 downto 6) /= "10" and IR(2 downto 1) = "11" and MCycle(2 downto 1) /= "00" else '1';
+ VP_n <= '0' when IRQCycle = '1' and (MCycle = "101" or MCycle = "110") else '1';
+ VDA <= '1' when Set_Addr_To_r /= "000" else '0'; -- Incorrect !!!!!!!!!!!!
+ VPA <= '1' when Jump(1) = '0' else '0'; -- Incorrect !!!!!!!!!!!!
+
+ mcode : T65_MCode
+ port map(
+ Mode => Mode_r,
+ IR => IR,
+ MCycle => MCycle,
+ P => P,
+ LCycle => LCycle,
+ ALU_Op => ALU_Op,
+ Set_BusA_To => Set_BusA_To,
+ Set_Addr_To => Set_Addr_To,
+ Write_Data => Write_Data,
+ Jump => Jump,
+ BAAdd => BAAdd,
+ BreakAtNA => BreakAtNA,
+ ADAdd => ADAdd,
+ AddY => AddY,
+ PCAdd => PCAdd,
+ Inc_S => Inc_S,
+ Dec_S => Dec_S,
+ LDA => LDA,
+ LDP => LDP,
+ LDX => LDX,
+ LDY => LDY,
+ LDS => LDS,
+ LDDI => LDDI,
+ LDALU => LDALU,
+ LDAD => LDAD,
+ LDBAL => LDBAL,
+ LDBAH => LDBAH,
+ SaveP => SaveP,
+ Write => Write
+ );
+
+ alu : T65_ALU
+ port map(
+ Mode => Mode_r,
+ Op => ALU_Op_r,
+ BusA => BusA_r,
+ BusB => BusB,
+ P_In => P,
+ P_Out => P_Out,
+ Q => ALU_Q
+ );
+
+ process (Res_n, Clk)
+ begin
+ if Res_n = '0' then
+ PC <= (others => '0'); -- Program Counter
+ IR <= "00000000";
+ S <= (others => '0'); -- Dummy !!!!!!!!!!!!!!!!!!!!!
+ D <= (others => '0');
+ PBR <= (others => '0');
+ DBR <= (others => '0');
+
+ Mode_r <= (others => '0');
+ ALU_Op_r <= "1100";
+ Write_Data_r <= "000";
+ Set_Addr_To_r <= "00";
+
+ R_W_n_i <= '1';
+ EF_i <= '1';
+ MF_i <= '1';
+ XF_i <= '1';
+
+ elsif Clk'event and Clk = '1' then
+ if (Enable = '1') then
+ if (really_rdy = '1') then
+ R_W_n_i <= not Write or RstCycle;
+
+ D <= (others => '1'); -- Dummy
+ PBR <= (others => '1'); -- Dummy
+ DBR <= (others => '1'); -- Dummy
+ EF_i <= '0'; -- Dummy
+ MF_i <= '0'; -- Dummy
+ XF_i <= '0'; -- Dummy
+
+ if MCycle = "000" then
+ Mode_r <= Mode;
+
+ if IRQCycle = '0' and NMICycle = '0' then
+ PC <= PC + 1;
+ end if;
+
+ if IRQCycle = '1' or NMICycle = '1' then
+ IR <= "00000000";
+ else
+ IR <= DI;
+ end if;
+ end if;
+
+ ALU_Op_r <= ALU_Op;
+ Write_Data_r <= Write_Data;
+ if Break = '1' then
+ Set_Addr_To_r <= "00";
+ else
+ Set_Addr_To_r <= Set_Addr_To;
+ end if;
+
+ if Inc_S = '1' then
+ S <= S + 1;
+ end if;
+ if Dec_S = '1' and RstCycle = '0' then
+ S <= S - 1;
+ end if;
+ if LDS = '1' then
+ S(7 downto 0) <= unsigned(ALU_Q);
+ end if;
+
+ if IR = "00000000" and MCycle = "001" and IRQCycle = '0' and NMICycle = '0' then
+ PC <= PC + 1;
+ end if;
+ --
+ -- jump control logic
+ --
+ case Jump is
+ when "01" =>
+ PC <= PC + 1;
+
+ when "10" =>
+ PC <= unsigned(DI & DL);
+
+ when "11" =>
+ if PCAdder(8) = '1' then
+ if DL(7) = '0' then
+ PC(15 downto 8) <= PC(15 downto 8) + 1;
+ else
+ PC(15 downto 8) <= PC(15 downto 8) - 1;
+ end if;
+ end if;
+ PC(7 downto 0) <= PCAdder(7 downto 0);
+
+ when others => null;
+ end case;
+ end if;
+ end if;
+ end if;
+ end process;
+
+ PCAdder <= resize(PC(7 downto 0),9) + resize(unsigned(DL(7) & DL),9) when PCAdd = '1'
+ else "0" & PC(7 downto 0);
+
+ process (Clk)
+ begin
+ if Clk'event and Clk = '1' then
+ if (Enable = '1') then
+ if (really_rdy = '1') then
+ if MCycle = "000" then
+ if LDA = '1' then
+ ABC(7 downto 0) <= ALU_Q;
+ end if;
+ if LDX = '1' then
+ X(7 downto 0) <= ALU_Q;
+ end if;
+ if LDY = '1' then
+ Y(7 downto 0) <= ALU_Q;
+ end if;
+ if (LDA or LDX or LDY) = '1' then
+ P <= P_Out;
+ end if;
+ end if;
+ if SaveP = '1' then
+ P <= P_Out;
+ end if;
+ if LDP = '1' then
+ P <= ALU_Q;
+ end if;
+ if IR(4 downto 0) = "11000" then
+ case IR(7 downto 5) is
+ when "000" =>
+ P(Flag_C) <= '0';
+ when "001" =>
+ P(Flag_C) <= '1';
+ when "010" =>
+ P(Flag_I) <= '0';
+ when "011" =>
+ P(Flag_I) <= '1';
+ when "101" =>
+ P(Flag_V) <= '0';
+ when "110" =>
+ P(Flag_D) <= '0';
+ when "111" =>
+ P(Flag_D) <= '1';
+ when others =>
+ end case;
+ end if;
+ if IR = "00000000" and MCycle = "011" and RstCycle = '0' and NMICycle = '0' and IRQCycle = '0' then
+ P(Flag_B) <= '1';
+ end if;
+ if IR = "00000000" and MCycle = "100" and RstCycle = '0' and (NMICycle = '1' or IRQCycle = '1') then
+ P(Flag_I) <= '1';
+ P(Flag_B) <= B_o;
+ end if;
+ if SO_n_o = '1' and SO_n = '0' then
+ P(Flag_V) <= '1';
+ end if;
+ if RstCycle = '1' and Mode_r /= "00" then
+ P(Flag_1) <= '1';
+ P(Flag_D) <= '0';
+ P(Flag_I) <= '1';
+ end if;
+ P(Flag_1) <= '1';
+
+ B_o <= P(Flag_B);
+ SO_n_o <= SO_n;
+ IRQ_n_o <= IRQ_n;
+ NMI_n_o <= NMI_n;
+ end if;
+ end if;
+ end if;
+ end process;
+
+---------------------------------------------------------------------------
+--
+-- Buses
+--
+---------------------------------------------------------------------------
+
+ process (Res_n, Clk)
+ begin
+ if Res_n = '0' then
+ BusA_r <= (others => '0');
+ BusB <= (others => '0');
+ AD <= (others => '0');
+ BAL <= (others => '0');
+ BAH <= (others => '0');
+ DL <= (others => '0');
+ elsif Clk'event and Clk = '1' then
+ if (Enable = '1') then
+ if (Rdy = '1') then
+ BusA_r <= BusA;
+ BusB <= DI;
+
+ case BAAdd is
+ when "01" =>
+ -- BA Inc
+ AD <= std_logic_vector(unsigned(AD) + 1);
+ BAL <= std_logic_vector(unsigned(BAL) + 1);
+ when "10" =>
+ -- BA Add
+ BAL <= std_logic_vector(resize(unsigned(BAL(7 downto 0)),9) + resize(unsigned(BusA),9));
+ when "11" =>
+ -- BA Adj
+ if BAL(8) = '1' then
+ BAH <= std_logic_vector(unsigned(BAH) + 1);
+ end if;
+ when others =>
+ end case;
+
+ -- ehenciak : modified to use Y register as well (bugfix)
+ if ADAdd = '1' then
+ if (AddY = '1') then
+ AD <= std_logic_vector(unsigned(AD) + unsigned(Y(7 downto 0)));
+ else
+ AD <= std_logic_vector(unsigned(AD) + unsigned(X(7 downto 0)));
+ end if;
+ end if;
+
+ if IR = "00000000" then
+ BAL <= (others => '1');
+ BAH <= (others => '1');
+ if RstCycle = '1' then
+ BAL(2 downto 0) <= "100";
+ elsif NMICycle = '1' then
+ BAL(2 downto 0) <= "010";
+ else
+ BAL(2 downto 0) <= "110";
+ end if;
+ if Set_addr_To_r = "11" then
+ BAL(0) <= '1';
+ end if;
+ end if;
+
+
+ if LDDI = '1' then
+ DL <= DI;
+ end if;
+ if LDALU = '1' then
+ DL <= ALU_Q;
+ end if;
+ if LDAD = '1' then
+ AD <= DI;
+ end if;
+ if LDBAL = '1' then
+ BAL(7 downto 0) <= DI;
+ end if;
+ if LDBAH = '1' then
+ BAH <= DI;
+ end if;
+ end if;
+ end if;
+ end if;
+ end process;
+
+ Break <= (BreakAtNA and not BAL(8)) or (PCAdd and not PCAdder(8));
+
+
+ with Set_BusA_To select
+ BusA <= DI when "000",
+ ABC(7 downto 0) when "001",
+ X(7 downto 0) when "010",
+ Y(7 downto 0) when "011",
+ std_logic_vector(S(7 downto 0)) when "100",
+ P when "101",
+ (others => '-') when others;
+
+ with Set_Addr_To_r select
+ A <= "0000000000000001" & std_logic_vector(S(7 downto 0)) when "01",
+ DBR & "00000000" & AD when "10",
+ "00000000" & BAH & BAL(7 downto 0) when "11",
+ PBR & std_logic_vector(PC(15 downto 8)) & std_logic_vector(PCAdder(7 downto 0)) when others;
+
+ with Write_Data_r select
+ DO <= DL when "000",
+ ABC(7 downto 0) when "001",
+ X(7 downto 0) when "010",
+ Y(7 downto 0) when "011",
+ std_logic_vector(S(7 downto 0)) when "100",
+ P when "101",
+ std_logic_vector(PC(7 downto 0)) when "110",
+ std_logic_vector(PC(15 downto 8)) when others;
+
+-------------------------------------------------------------------------
+--
+-- Main state machine
+--
+-------------------------------------------------------------------------
+
+ process (Res_n, Clk)
+ begin
+ if Res_n = '0' then
+ MCycle <= "001";
+ RstCycle <= '1';
+ IRQCycle <= '0';
+ NMICycle <= '0';
+ NMIAct <= '0';
+ elsif Clk'event and Clk = '1' then
+ if (Enable = '1') then
+ if (really_rdy = '1') then
+ if MCycle = LCycle or Break = '1' then
+ MCycle <= "000";
+ RstCycle <= '0';
+ IRQCycle <= '0';
+ NMICycle <= '0';
+ if NMIAct = '1' then
+ NMICycle <= '1';
+ elsif IRQ_n_o = '0' and P(Flag_I) = '0' then
+ IRQCycle <= '1';
+ end if;
+ else
+ MCycle <= std_logic_vector(unsigned(MCycle) + 1);
+ end if;
+
+ if NMICycle = '1' then
+ NMIAct <= '0';
+ end if;
+ if NMI_n_o = '1' and NMI_n = '0' then
+ NMIAct <= '1';
+ end if;
+ end if;
+ end if;
+ end if;
+ end process;
+
+end;
diff --git a/T65/T65_ALU.vhd b/T65/T65_ALU.vhd new file mode 100644 index 0000000..d9d25e1 --- /dev/null +++ b/T65/T65_ALU.vhd @@ -0,0 +1,260 @@ +-- ****
+-- T65(b) core. In an effort to merge and maintain bug fixes ....
+--
+--
+-- Ver 300 Bugfixes by ehenciak added
+-- MikeJ March 2005
+-- Latest version from www.fpgaarcade.com (original www.opencores.org)
+--
+-- ****
+--
+-- 6502 compatible microprocessor core
+--
+-- Version : 0245
+--
+-- Copyright (c) 2002 Daniel Wallner (jesus@opencores.org)
+--
+-- All rights reserved
+--
+-- Redistribution and use in source and synthezised forms, with or without
+-- modification, are permitted provided that the following conditions are met:
+--
+-- Redistributions of source code must retain the above copyright notice,
+-- this list of conditions and the following disclaimer.
+--
+-- Redistributions in synthesized form must reproduce the above copyright
+-- notice, this list of conditions and the following disclaimer in the
+-- documentation and/or other materials provided with the distribution.
+--
+-- Neither the name of the author nor the names of other contributors may
+-- be used to endorse or promote products derived from this software without
+-- specific prior written permission.
+--
+-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+-- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+-- THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+-- PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE
+-- LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+-- CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+-- SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+-- INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+-- CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+-- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+-- POSSIBILITY OF SUCH DAMAGE.
+--
+-- Please report bugs to the author, but before you do so, please
+-- make sure that this is not a derivative work and that
+-- you have the latest version of this file.
+--
+-- The latest version of this file can be found at:
+-- http://www.opencores.org/cvsweb.shtml/t65/
+--
+-- Limitations :
+--
+-- File history :
+--
+-- 0245 : First version
+--
+
+library IEEE;
+use IEEE.std_logic_1164.all;
+use IEEE.numeric_std.all;
+use work.T65_Pack.all;
+
+entity T65_ALU is
+ port(
+ Mode : in std_logic_vector(1 downto 0); -- "00" => 6502, "01" => 65C02, "10" => 65816
+ Op : in std_logic_vector(3 downto 0);
+ BusA : in std_logic_vector(7 downto 0);
+ BusB : in std_logic_vector(7 downto 0);
+ P_In : in std_logic_vector(7 downto 0);
+ P_Out : out std_logic_vector(7 downto 0);
+ Q : out std_logic_vector(7 downto 0)
+ );
+end T65_ALU;
+
+architecture rtl of T65_ALU is
+
+ -- AddSub variables (temporary signals)
+ signal ADC_Z : std_logic;
+ signal ADC_C : std_logic;
+ signal ADC_V : std_logic;
+ signal ADC_N : std_logic;
+ signal ADC_Q : std_logic_vector(7 downto 0);
+ signal SBC_Z : std_logic;
+ signal SBC_C : std_logic;
+ signal SBC_V : std_logic;
+ signal SBC_N : std_logic;
+ signal SBC_Q : std_logic_vector(7 downto 0);
+
+begin
+
+ process (P_In, BusA, BusB)
+ variable AL : unsigned(6 downto 0);
+ variable AH : unsigned(6 downto 0);
+ variable C : std_logic;
+ begin
+ AL := resize(unsigned(BusA(3 downto 0) & P_In(Flag_C)), 7) + resize(unsigned(BusB(3 downto 0) & "1"), 7);
+ AH := resize(unsigned(BusA(7 downto 4) & AL(5)), 7) + resize(unsigned(BusB(7 downto 4) & "1"), 7);
+
+-- pragma translate_off
+ if is_x(std_logic_vector(AL)) then AL := "0000000"; end if;
+ if is_x(std_logic_vector(AH)) then AH := "0000000"; end if;
+-- pragma translate_on
+
+ if AL(4 downto 1) = 0 and AH(4 downto 1) = 0 then
+ ADC_Z <= '1';
+ else
+ ADC_Z <= '0';
+ end if;
+
+ if AL(5 downto 1) > 9 and P_In(Flag_D) = '1' then
+ AL(6 downto 1) := AL(6 downto 1) + 6;
+ end if;
+
+ C := AL(6) or AL(5);
+ AH := resize(unsigned(BusA(7 downto 4) & C), 7) + resize(unsigned(BusB(7 downto 4) & "1"), 7);
+
+ ADC_N <= AH(4);
+ ADC_V <= (AH(4) xor BusA(7)) and not (BusA(7) xor BusB(7));
+
+-- pragma translate_off
+ if is_x(std_logic_vector(AH)) then AH := "0000000"; end if;
+-- pragma translate_on
+
+ if AH(5 downto 1) > 9 and P_In(Flag_D) = '1' then
+ AH(6 downto 1) := AH(6 downto 1) + 6;
+ end if;
+
+ ADC_C <= AH(6) or AH(5);
+
+ ADC_Q <= std_logic_vector(AH(4 downto 1) & AL(4 downto 1));
+ end process;
+
+ process (Op, P_In, BusA, BusB)
+ variable AL : unsigned(6 downto 0);
+ variable AH : unsigned(5 downto 0);
+ variable C : std_logic;
+ begin
+ C := P_In(Flag_C) or not Op(0);
+ AL := resize(unsigned(BusA(3 downto 0) & C), 7) - resize(unsigned(BusB(3 downto 0) & "1"), 6);
+ AH := resize(unsigned(BusA(7 downto 4) & "0"), 6) - resize(unsigned(BusB(7 downto 4) & AL(5)), 6);
+
+-- pragma translate_off
+ if is_x(std_logic_vector(AL)) then AL := "0000000"; end if;
+ if is_x(std_logic_vector(AH)) then AH := "000000"; end if;
+-- pragma translate_on
+
+ if AL(4 downto 1) = 0 and AH(4 downto 1) = 0 then
+ SBC_Z <= '1';
+ else
+ SBC_Z <= '0';
+ end if;
+
+ SBC_C <= not AH(5);
+ SBC_V <= (AH(4) xor BusA(7)) and (BusA(7) xor BusB(7));
+ SBC_N <= AH(4);
+
+ if P_In(Flag_D) = '1' then
+ if AL(5) = '1' then
+ AL(5 downto 1) := AL(5 downto 1) - 6;
+ end if;
+ AH := resize(unsigned(BusA(7 downto 4) & "0"), 6) - resize(unsigned(BusB(7 downto 4) & AL(6)), 6);
+ if AH(5) = '1' then
+ AH(5 downto 1) := AH(5 downto 1) - 6;
+ end if;
+ end if;
+
+ SBC_Q <= std_logic_vector(AH(4 downto 1) & AL(4 downto 1));
+ end process;
+
+ process (Op, P_In, BusA, BusB,
+ ADC_Z, ADC_C, ADC_V, ADC_N, ADC_Q,
+ SBC_Z, SBC_C, SBC_V, SBC_N, SBC_Q)
+ variable Q_t : std_logic_vector(7 downto 0);
+ begin
+ -- ORA, AND, EOR, ADC, NOP, LD, CMP, SBC
+ -- ASL, ROL, LSR, ROR, BIT, LD, DEC, INC
+ P_Out <= P_In;
+ Q_t := BusA;
+ case Op(3 downto 0) is
+ when "0000" =>
+ -- ORA
+ Q_t := BusA or BusB;
+ when "0001" =>
+ -- AND
+ Q_t := BusA and BusB;
+ when "0010" =>
+ -- EOR
+ Q_t := BusA xor BusB;
+ when "0011" =>
+ -- ADC
+ P_Out(Flag_V) <= ADC_V;
+ P_Out(Flag_C) <= ADC_C;
+ Q_t := ADC_Q;
+ when "0101" | "1101" =>
+ -- LDA
+ when "0110" =>
+ -- CMP
+ P_Out(Flag_C) <= SBC_C;
+ when "0111" =>
+ -- SBC
+ P_Out(Flag_V) <= SBC_V;
+ P_Out(Flag_C) <= SBC_C;
+ Q_t := SBC_Q;
+ when "1000" =>
+ -- ASL
+ Q_t := BusA(6 downto 0) & "0";
+ P_Out(Flag_C) <= BusA(7);
+ when "1001" =>
+ -- ROL
+ Q_t := BusA(6 downto 0) & P_In(Flag_C);
+ P_Out(Flag_C) <= BusA(7);
+ when "1010" =>
+ -- LSR
+ Q_t := "0" & BusA(7 downto 1);
+ P_Out(Flag_C) <= BusA(0);
+ when "1011" =>
+ -- ROR
+ Q_t := P_In(Flag_C) & BusA(7 downto 1);
+ P_Out(Flag_C) <= BusA(0);
+ when "1100" =>
+ -- BIT
+ P_Out(Flag_V) <= BusB(6);
+ when "1110" =>
+ -- DEC
+ Q_t := std_logic_vector(unsigned(BusA) - 1);
+ when "1111" =>
+ -- INC
+ Q_t := std_logic_vector(unsigned(BusA) + 1);
+ when others =>
+ end case;
+
+ case Op(3 downto 0) is
+ when "0011" =>
+ P_Out(Flag_N) <= ADC_N;
+ P_Out(Flag_Z) <= ADC_Z;
+ when "0110" | "0111" =>
+ P_Out(Flag_N) <= SBC_N;
+ P_Out(Flag_Z) <= SBC_Z;
+ when "0100" =>
+ when "1100" =>
+ P_Out(Flag_N) <= BusB(7);
+ if (BusA and BusB) = "00000000" then
+ P_Out(Flag_Z) <= '1';
+ else
+ P_Out(Flag_Z) <= '0';
+ end if;
+ when others =>
+ P_Out(Flag_N) <= Q_t(7);
+ if Q_t = "00000000" then
+ P_Out(Flag_Z) <= '1';
+ else
+ P_Out(Flag_Z) <= '0';
+ end if;
+ end case;
+
+ Q <= Q_t;
+ end process;
+
+end;
diff --git a/T65/T65_MCode.vhd b/T65/T65_MCode.vhd new file mode 100644 index 0000000..3fd40d8 --- /dev/null +++ b/T65/T65_MCode.vhd @@ -0,0 +1,1052 @@ +-- ****
+-- T65(b) core. In an effort to merge and maintain bug fixes ....
+--
+--
+-- Ver 302 minor timing fixes
+-- Ver 301 Jump timing fixed
+-- Ver 300 Bugfixes by ehenciak added
+-- MikeJ March 2005
+-- Latest version from www.fpgaarcade.com (original www.opencores.org)
+--
+-- ****
+--
+-- 65xx compatible microprocessor core
+--
+-- Version : 0246 + fix
+--
+-- Copyright (c) 2002 Daniel Wallner (jesus@opencores.org)
+--
+-- All rights reserved
+--
+-- Redistribution and use in source and synthezised forms, with or without
+-- modification, are permitted provided that the following conditions are met:
+--
+-- Redistributions of source code must retain the above copyright notice,
+-- this list of conditions and the following disclaimer.
+--
+-- Redistributions in synthesized form must reproduce the above copyright
+-- notice, this list of conditions and the following disclaimer in the
+-- documentation and/or other materials provided with the distribution.
+--
+-- Neither the name of the author nor the names of other contributors may
+-- be used to endorse or promote products derived from this software without
+-- specific prior written permission.
+--
+-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+-- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+-- THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+-- PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE
+-- LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+-- CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+-- SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+-- INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+-- CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+-- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+-- POSSIBILITY OF SUCH DAMAGE.
+--
+-- Please report bugs to the author, but before you do so, please
+-- make sure that this is not a derivative work and that
+-- you have the latest version of this file.
+--
+-- The latest version of this file can be found at:
+-- http://www.opencores.org/cvsweb.shtml/t65/
+--
+-- Limitations :
+--
+-- 65C02
+-- supported : inc, dec, phx, plx, phy, ply
+-- missing : bra, ora, lda, cmp, sbc, tsb*2, trb*2, stz*2, bit*2, wai, stp, jmp, bbr*8, bbs*8
+--
+-- File history :
+--
+-- 0246 : First release
+--
+
+library IEEE;
+use IEEE.std_logic_1164.all;
+use IEEE.numeric_std.all;
+use work.T65_Pack.all;
+
+entity T65_MCode is
+ port(
+ Mode : in std_logic_vector(1 downto 0); -- "00" => 6502, "01" => 65C02, "10" => 65816
+ IR : in std_logic_vector(7 downto 0);
+ MCycle : in std_logic_vector(2 downto 0);
+ P : in std_logic_vector(7 downto 0);
+ LCycle : out std_logic_vector(2 downto 0);
+ ALU_Op : out std_logic_vector(3 downto 0);
+ Set_BusA_To : out std_logic_vector(2 downto 0); -- DI,A,X,Y,S,P
+ Set_Addr_To : out std_logic_vector(1 downto 0); -- PC Adder,S,AD,BA
+ Write_Data : out std_logic_vector(2 downto 0); -- DL,A,X,Y,S,P,PCL,PCH
+ Jump : out std_logic_vector(1 downto 0); -- PC,++,DIDL,Rel
+ BAAdd : out std_logic_vector(1 downto 0); -- None,DB Inc,BA Add,BA Adj
+ BreakAtNA : out std_logic;
+ ADAdd : out std_logic;
+ AddY : out std_logic;
+ PCAdd : out std_logic;
+ Inc_S : out std_logic;
+ Dec_S : out std_logic;
+ LDA : out std_logic;
+ LDP : out std_logic;
+ LDX : out std_logic;
+ LDY : out std_logic;
+ LDS : out std_logic;
+ LDDI : out std_logic;
+ LDALU : out std_logic;
+ LDAD : out std_logic;
+ LDBAL : out std_logic;
+ LDBAH : out std_logic;
+ SaveP : out std_logic;
+ Write : out std_logic
+ );
+end T65_MCode;
+
+architecture rtl of T65_MCode is
+
+ signal Branch : std_logic;
+
+begin
+
+ with IR(7 downto 5) select
+ Branch <= not P(Flag_N) when "000",
+ P(Flag_N) when "001",
+ not P(Flag_V) when "010",
+ P(Flag_V) when "011",
+ not P(Flag_C) when "100",
+ P(Flag_C) when "101",
+ not P(Flag_Z) when "110",
+ P(Flag_Z) when others;
+
+ process (IR, MCycle, P, Branch, Mode)
+ begin
+ LCycle <= "001";
+ Set_BusA_To <= "001"; -- A
+ Set_Addr_To <= (others => '0');
+ Write_Data <= (others => '0');
+ Jump <= (others => '0');
+ BAAdd <= "00";
+ BreakAtNA <= '0';
+ ADAdd <= '0';
+ PCAdd <= '0';
+ Inc_S <= '0';
+ Dec_S <= '0';
+ LDA <= '0';
+ LDP <= '0';
+ LDX <= '0';
+ LDY <= '0';
+ LDS <= '0';
+ LDDI <= '0';
+ LDALU <= '0';
+ LDAD <= '0';
+ LDBAL <= '0';
+ LDBAH <= '0';
+ SaveP <= '0';
+ Write <= '0';
+ AddY <= '0';
+
+ case IR(7 downto 5) is
+ when "100" =>
+ --{{{
+ case IR(1 downto 0) is
+ when "00" =>
+ Set_BusA_To <= "011"; -- Y
+ Write_Data <= "011"; -- Y
+ when "10" =>
+ Set_BusA_To <= "010"; -- X
+ Write_Data <= "010"; -- X
+ when others =>
+ Write_Data <= "001"; -- A
+ end case;
+ --}}}
+ when "101" =>
+ --{{{
+ case IR(1 downto 0) is
+ when "00" =>
+ if IR(4) /= '1' or IR(2) /= '0' then
+ LDY <= '1';
+ end if;
+ when "10" =>
+ LDX <= '1';
+ when others =>
+ LDA <= '1';
+ end case;
+ Set_BusA_To <= "000"; -- DI
+ --}}}
+ when "110" =>
+ --{{{
+ case IR(1 downto 0) is
+ when "00" =>
+ if IR(4) = '0' then
+ LDY <= '1';
+ end if;
+ Set_BusA_To <= "011"; -- Y
+ when others =>
+ Set_BusA_To <= "001"; -- A
+ end case;
+ --}}}
+ when "111" =>
+ --{{{
+ case IR(1 downto 0) is
+ when "00" =>
+ if IR(4) = '0' then
+ LDX <= '1';
+ end if;
+ Set_BusA_To <= "010"; -- X
+ when others =>
+ Set_BusA_To <= "001"; -- A
+ end case;
+ --}}}
+ when others =>
+ end case;
+
+ if IR(7 downto 6) /= "10" and IR(1 downto 0) = "10" then
+ Set_BusA_To <= "000"; -- DI
+ end if;
+
+ case IR(4 downto 0) is
+ when "00000" | "01000" | "01010" | "11000" | "11010" =>
+ --{{{
+ -- Implied
+ case IR is
+ when "00000000" =>
+ -- BRK
+ LCycle <= "110";
+ case to_integer(unsigned(MCycle)) is
+ when 1 =>
+ Set_Addr_To <= "01"; -- S
+ Write_Data <= "111"; -- PCH
+ Write <= '1';
+ when 2 =>
+ Dec_S <= '1';
+ Set_Addr_To <= "01"; -- S
+ Write_Data <= "110"; -- PCL
+ Write <= '1';
+ when 3 =>
+ Dec_S <= '1';
+ Set_Addr_To <= "01"; -- S
+ Write_Data <= "101"; -- P
+ Write <= '1';
+ when 4 =>
+ Dec_S <= '1';
+ Set_Addr_To <= "11"; -- BA
+ when 5 =>
+ LDDI <= '1';
+ Set_Addr_To <= "11"; -- BA
+ when 6 =>
+ Jump <= "10"; -- DIDL
+ when others =>
+ end case;
+ when "00100000" =>
+ -- JSR
+ LCycle <= "101";
+ case to_integer(unsigned(MCycle)) is
+ when 1 =>
+ Jump <= "01";
+ LDDI <= '1';
+ Set_Addr_To <= "01"; -- S
+ when 2 =>
+ Set_Addr_To <= "01"; -- S
+ Write_Data <= "111"; -- PCH
+ Write <= '1';
+ when 3 =>
+ Dec_S <= '1';
+ Set_Addr_To <= "01"; -- S
+ Write_Data <= "110"; -- PCL
+ Write <= '1';
+ when 4 =>
+ Dec_S <= '1';
+ when 5 =>
+ Jump <= "10"; -- DIDL
+ when others =>
+ end case;
+ when "01000000" =>
+ -- RTI
+ LCycle <= "101";
+ case to_integer(unsigned(MCycle)) is
+ when 1 =>
+ Set_Addr_To <= "01"; -- S
+ when 2 =>
+ Inc_S <= '1';
+ Set_Addr_To <= "01"; -- S
+ when 3 =>
+ Inc_S <= '1';
+ Set_Addr_To <= "01"; -- S
+ Set_BusA_To <= "000"; -- DI
+ when 4 =>
+ LDP <= '1';
+ Inc_S <= '1';
+ LDDI <= '1';
+ Set_Addr_To <= "01"; -- S
+ when 5 =>
+ Jump <= "10"; -- DIDL
+ when others =>
+ end case;
+ when "01100000" =>
+ -- RTS
+ LCycle <= "101";
+ case to_integer(unsigned(MCycle)) is
+ when 1 =>
+ Set_Addr_To <= "01"; -- S
+ when 2 =>
+ Inc_S <= '1';
+ Set_Addr_To <= "01"; -- S
+ when 3 =>
+ Inc_S <= '1';
+ LDDI <= '1';
+ Set_Addr_To <= "01"; -- S
+ when 4 =>
+ Jump <= "10"; -- DIDL
+ when 5 =>
+ Jump <= "01";
+ when others =>
+ end case;
+ when "00001000" | "01001000" | "01011010" | "11011010" =>
+ -- PHP, PHA, PHY*, PHX*
+ LCycle <= "010";
+ if Mode = "00" and IR(1) = '1' then
+ LCycle <= "001";
+ end if;
+ case to_integer(unsigned(MCycle)) is
+ when 1 =>
+ case IR(7 downto 4) is
+ when "0000" =>
+ Write_Data <= "101"; -- P
+ when "0100" =>
+ Write_Data <= "001"; -- A
+ when "0101" =>
+ Write_Data <= "011"; -- Y
+ when "1101" =>
+ Write_Data <= "010"; -- X
+ when others =>
+ end case;
+ Write <= '1';
+ Set_Addr_To <= "01"; -- S
+ when 2 =>
+ Dec_S <= '1';
+ when others =>
+ end case;
+ when "00101000" | "01101000" | "01111010" | "11111010" =>
+ -- PLP, PLA, PLY*, PLX*
+ LCycle <= "011";
+ if Mode = "00" and IR(1) = '1' then
+ LCycle <= "001";
+ end if;
+ case IR(7 downto 4) is
+ when "0010" =>
+ LDP <= '1';
+ when "0110" =>
+ LDA <= '1';
+ when "0111" =>
+ if Mode /= "00" then
+ LDY <= '1';
+ end if;
+ when "1111" =>
+ if Mode /= "00" then
+ LDX <= '1';
+ end if;
+ when others =>
+ end case;
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ SaveP <= '1';
+ when 1 =>
+ Set_Addr_To <= "01"; -- S
+ when 2 =>
+ Inc_S <= '1';
+ Set_Addr_To <= "01"; -- S
+ when 3 =>
+ Set_BusA_To <= "000"; -- DI
+ when others =>
+ end case;
+ when "10100000" | "11000000" | "11100000" =>
+ -- LDY, CPY, CPX
+ -- Immediate
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ when 1 =>
+ Jump <= "01";
+ when others =>
+ end case;
+ when "10001000" =>
+ -- DEY
+ LDY <= '1';
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ when 1 =>
+ Set_BusA_To <= "011"; -- Y
+ when others =>
+ end case;
+ when "11001010" =>
+ -- DEX
+ LDX <= '1';
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ when 1 =>
+ Set_BusA_To <= "010"; -- X
+ when others =>
+ end case;
+ when "00011010" | "00111010" =>
+ -- INC*, DEC*
+ if Mode /= "00" then
+ LDA <= '1'; -- A
+ end if;
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ when 1 =>
+ Set_BusA_To <= "100"; -- S
+ when others =>
+ end case;
+ when "00001010" | "00101010" | "01001010" | "01101010" =>
+ -- ASL, ROL, LSR, ROR
+ LDA <= '1'; -- A
+ Set_BusA_To <= "001"; -- A
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ when 1 =>
+ when others =>
+ end case;
+ when "10001010" | "10011000" =>
+ -- TYA, TXA
+ LDA <= '1'; -- A
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ when 1 =>
+ when others =>
+ end case;
+ when "10101010" | "10101000" =>
+ -- TAX, TAY
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ when 1 =>
+ Set_BusA_To <= "001"; -- A
+ when others =>
+ end case;
+ when "10011010" =>
+ -- TXS
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ LDS <= '1';
+ when 1 =>
+ when others =>
+ end case;
+ when "10111010" =>
+ -- TSX
+ LDX <= '1';
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ when 1 =>
+ Set_BusA_To <= "100"; -- S
+ when others =>
+ end case;
+
+ -- when "00011000" | "00111000" | "01011000" | "01111000" | "10111000" | "11011000" | "11111000" | "11001000" | "11101000" =>
+ -- -- CLC, SEC, CLI, SEI, CLV, CLD, SED, INY, INX
+ -- case to_integer(unsigned(MCycle)) is
+ -- when 1 =>
+ -- when others =>
+ -- end case;
+ when others =>
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ when others =>
+ end case;
+ end case;
+ --}}}
+
+ when "00001" | "00011" =>
+ --{{{
+ -- Zero Page Indexed Indirect (d,x)
+ LCycle <= "101";
+ if IR(7 downto 6) /= "10" then
+ LDA <= '1';
+ end if;
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ when 1 =>
+ Jump <= "01";
+ LDAD <= '1';
+ Set_Addr_To <= "10"; -- AD
+ when 2 =>
+ ADAdd <= '1';
+ Set_Addr_To <= "10"; -- AD
+ when 3 =>
+ BAAdd <= "01"; -- DB Inc
+ LDBAL <= '1';
+ Set_Addr_To <= "10"; -- AD
+ when 4 =>
+ LDBAH <= '1';
+ if IR(7 downto 5) = "100" then
+ Write <= '1';
+ end if;
+ Set_Addr_To <= "11"; -- BA
+ when 5 =>
+ when others =>
+ end case;
+ --}}}
+
+ when "01001" | "01011" =>
+ --{{{
+ -- Immediate
+ LDA <= '1';
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ when 1 =>
+ Jump <= "01";
+ when others =>
+ end case;
+
+ --}}}
+
+ when "00010" | "10010" =>
+ --{{{
+ -- Immediate, KIL
+ LDX <= '1';
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ when 1 =>
+ if IR = "10100010" then
+ -- LDX
+ Jump <= "01";
+ else
+ -- KIL !!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+ end if;
+ when others =>
+ end case;
+ --}}}
+
+ when "00100" =>
+ --{{{
+ -- Zero Page
+ LCycle <= "010";
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ if IR(7 downto 5) = "001" then
+ SaveP <= '1';
+ end if;
+ when 1 =>
+ Jump <= "01";
+ LDAD <= '1';
+ if IR(7 downto 5) = "100" then
+ Write <= '1';
+ end if;
+ Set_Addr_To <= "10"; -- AD
+ when 2 =>
+ when others =>
+ end case;
+ --}}}
+
+ when "00101" | "00110" | "00111" =>
+ --{{{
+ -- Zero Page
+ if IR(7 downto 6) /= "10" and IR(1 downto 0) = "10" then
+ -- Read-Modify-Write
+ LCycle <= "100";
+ case to_integer(unsigned(MCycle)) is
+ when 1 =>
+ Jump <= "01";
+ LDAD <= '1';
+ Set_Addr_To <= "10"; -- AD
+ when 2 =>
+ LDDI <= '1';
+ Write <= '1';
+ Set_Addr_To <= "10"; -- AD
+ when 3 =>
+ LDALU <= '1';
+ SaveP <= '1';
+ Write <= '1';
+ Set_Addr_To <= "10"; -- AD
+ when 4 =>
+ when others =>
+ end case;
+ else
+ LCycle <= "010";
+ if IR(7 downto 6) /= "10" then
+ LDA <= '1';
+ end if;
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ when 1 =>
+ Jump <= "01";
+ LDAD <= '1';
+ if IR(7 downto 5) = "100" then
+ Write <= '1';
+ end if;
+ Set_Addr_To <= "10"; -- AD
+ when 2 =>
+ when others =>
+ end case;
+ end if;
+ --}}}
+
+ when "01100" =>
+ --{{{
+ -- Absolute
+ if IR(7 downto 6) = "01" and IR(4 downto 0) = "01100" then
+ -- JMP
+ if IR(5) = '0' then
+ --LCycle <= "011";
+ LCycle <= "010";
+ case to_integer(unsigned(MCycle)) is
+ when 1 =>
+ Jump <= "01";
+ LDDI <= '1';
+ when 2 =>
+ Jump <= "10"; -- DIDL
+ when others =>
+ end case;
+ else
+ --LCycle <= "101";
+ LCycle <= "100"; -- mikej
+ case to_integer(unsigned(MCycle)) is
+ when 1 =>
+ Jump <= "01";
+ LDDI <= '1';
+ LDBAL <= '1';
+ when 2 =>
+ LDBAH <= '1';
+ if Mode /= "00" then
+ Jump <= "10"; -- DIDL
+ end if;
+ if Mode = "00" then
+ Set_Addr_To <= "11"; -- BA
+ end if;
+ when 3 =>
+ LDDI <= '1';
+ if Mode = "00" then
+ Set_Addr_To <= "11"; -- BA
+ BAAdd <= "01"; -- DB Inc
+ else
+ Jump <= "01";
+ end if;
+ when 4 =>
+ Jump <= "10"; -- DIDL
+ when others =>
+ end case;
+ end if;
+ else
+ LCycle <= "011";
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ if IR(7 downto 5) = "001" then
+ SaveP <= '1';
+ end if;
+ when 1 =>
+ Jump <= "01";
+ LDBAL <= '1';
+ when 2 =>
+ Jump <= "01";
+ LDBAH <= '1';
+ if IR(7 downto 5) = "100" then
+ Write <= '1';
+ end if;
+ Set_Addr_To <= "11"; -- BA
+ when 3 =>
+ when others =>
+ end case;
+ end if;
+ --}}}
+
+ when "01101" | "01110" | "01111" =>
+ --{{{
+ -- Absolute
+ if IR(7 downto 6) /= "10" and IR(1 downto 0) = "10" then
+ -- Read-Modify-Write
+ LCycle <= "101";
+ case to_integer(unsigned(MCycle)) is
+ when 1 =>
+ Jump <= "01";
+ LDBAL <= '1';
+ when 2 =>
+ Jump <= "01";
+ LDBAH <= '1';
+ Set_Addr_To <= "11"; -- BA
+ when 3 =>
+ LDDI <= '1';
+ Write <= '1';
+ Set_Addr_To <= "11"; -- BA
+ when 4 =>
+ Write <= '1';
+ LDALU <= '1';
+ SaveP <= '1';
+ Set_Addr_To <= "11"; -- BA
+ when 5 =>
+ SaveP <= '0'; -- MIKEJ was 1
+ when others =>
+ end case;
+ else
+ LCycle <= "011";
+ if IR(7 downto 6) /= "10" then
+ LDA <= '1';
+ end if;
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ when 1 =>
+ Jump <= "01";
+ LDBAL <= '1';
+ when 2 =>
+ Jump <= "01";
+ LDBAH <= '1';
+ if IR(7 downto 5) = "100" then
+ Write <= '1';
+ end if;
+ Set_Addr_To <= "11"; -- BA
+ when 3 =>
+ when others =>
+ end case;
+ end if;
+ --}}}
+
+ when "10000" =>
+ --{{{
+ -- Relative
+
+ -- This circuit dictates when the last
+ -- microcycle occurs for the branch depending on
+ -- whether or not the branch is taken and if a page
+ -- is crossed...
+ if (Branch = '1') then
+
+ LCycle <= "011"; -- We're done @ T3 if branching...upper
+ -- level logic will stop at T2 if no page cross
+ -- (See the Break signal)
+ else
+
+ LCycle <= "001";
+
+ end if;
+
+ -- This decodes the current microcycle and takes the
+ -- proper course of action...
+ case to_integer(unsigned(MCycle)) is
+
+ -- On the T1 microcycle, increment the program counter
+ -- and instruct the upper level logic to fetch the offset
+ -- from the Din bus and store it in the data latches. This
+ -- will be the last microcycle if the branch isn't taken.
+ when 1 =>
+
+ Jump <= "01"; -- Increments the PC by one (PC will now be PC+2)
+ -- from microcycle T0.
+
+ LDDI <= '1'; -- Tells logic in top level (T65.vhd) to route
+ -- the Din bus to the memory data latch (DL)
+ -- so that the branch offset is fetched.
+
+ -- In microcycle T2, tell the logic in the top level to
+ -- add the offset. If the most significant byte of the
+ -- program counter (i.e. the current "page") does not need
+ -- updating, we are done here...the Break signal at the
+ -- T65.vhd level takes care of that...
+ when 2 =>
+
+ Jump <= "11"; -- Tell the PC Jump logic to use relative mode.
+
+ PCAdd <= '1'; -- This tells the PC adder to update itself with
+ -- the current offset recently fetched from
+ -- memory.
+
+ -- The following is microcycle T3 :
+ -- The program counter should be completely updated
+ -- on this cycle after the page cross is detected.
+ -- We don't need to do anything here...
+ when 3 =>
+
+
+ when others => null; -- Do nothing.
+
+ end case;
+ --}}}
+
+ when "10001" | "10011" =>
+ --{{{
+ -- Zero Page Indirect Indexed (d),y
+ LCycle <= "101";
+ if IR(7 downto 6) /= "10" then
+ LDA <= '1';
+ end if;
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ when 1 =>
+ Jump <= "01";
+ LDAD <= '1';
+ Set_Addr_To <= "10"; -- AD
+ when 2 =>
+ LDBAL <= '1';
+ BAAdd <= "01"; -- DB Inc
+ Set_Addr_To <= "10"; -- AD
+ when 3 =>
+ Set_BusA_To <= "011"; -- Y
+ BAAdd <= "10"; -- BA Add
+ LDBAH <= '1';
+ Set_Addr_To <= "11"; -- BA
+ when 4 =>
+ BAAdd <= "11"; -- BA Adj
+ if IR(7 downto 5) = "100" then
+ Write <= '1';
+ else
+ BreakAtNA <= '1';
+ end if;
+ Set_Addr_To <= "11"; -- BA
+ when 5 =>
+ when others =>
+ end case;
+ --}}}
+
+ when "10100" | "10101" | "10110" | "10111" =>
+ --{{{
+ -- Zero Page, X
+ if IR(7 downto 6) /= "10" and IR(1 downto 0) = "10" then
+ -- Read-Modify-Write
+ LCycle <= "101";
+ case to_integer(unsigned(MCycle)) is
+ when 1 =>
+ Jump <= "01";
+ LDAD <= '1';
+ Set_Addr_To <= "10"; -- AD
+ when 2 =>
+ ADAdd <= '1';
+ Set_Addr_To <= "10"; -- AD
+ when 3 =>
+ LDDI <= '1';
+ Write <= '1';
+ Set_Addr_To <= "10"; -- AD
+ when 4 =>
+ LDALU <= '1';
+ SaveP <= '1';
+ Write <= '1';
+ Set_Addr_To <= "10"; -- AD
+ when 5 =>
+ when others =>
+ end case;
+ else
+ LCycle <= "011";
+ if IR(7 downto 6) /= "10" then
+ LDA <= '1';
+ end if;
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ when 1 =>
+ Jump <= "01";
+ LDAD <= '1';
+ Set_Addr_To <= "10"; -- AD
+ when 2 =>
+ ADAdd <= '1';
+ -- Added this check for Y reg. use...
+ if (IR(3 downto 0) = "0110") then
+ AddY <= '1';
+ end if;
+
+ if IR(7 downto 5) = "100" then
+ Write <= '1';
+ end if;
+ Set_Addr_To <= "10"; -- AD
+ when 3 => null;
+ when others =>
+ end case;
+ end if;
+ --}}}
+
+ when "11001" | "11011" =>
+ --{{{
+ -- Absolute Y
+ LCycle <= "100";
+ if IR(7 downto 6) /= "10" then
+ LDA <= '1';
+ end if;
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ when 1 =>
+ Jump <= "01";
+ LDBAL <= '1';
+ when 2 =>
+ Jump <= "01";
+ Set_BusA_To <= "011"; -- Y
+ BAAdd <= "10"; -- BA Add
+ LDBAH <= '1';
+ Set_Addr_To <= "11"; -- BA
+ when 3 =>
+ BAAdd <= "11"; -- BA adj
+ if IR(7 downto 5) = "100" then
+ Write <= '1';
+ else
+ BreakAtNA <= '1';
+ end if;
+ Set_Addr_To <= "11"; -- BA
+ when 4 =>
+ when others =>
+ end case;
+ --}}}
+
+ when "11100" | "11101" | "11110" | "11111" =>
+ --{{{
+ -- Absolute X
+
+ if IR(7 downto 6) /= "10" and IR(1 downto 0) = "10" then
+ -- Read-Modify-Write
+ LCycle <= "110";
+ case to_integer(unsigned(MCycle)) is
+ when 1 =>
+ Jump <= "01";
+ LDBAL <= '1';
+ when 2 =>
+ Jump <= "01";
+ Set_BusA_To <= "010"; -- X
+ BAAdd <= "10"; -- BA Add
+ LDBAH <= '1';
+ Set_Addr_To <= "11"; -- BA
+ when 3 =>
+ BAAdd <= "11"; -- BA adj
+ Set_Addr_To <= "11"; -- BA
+ when 4 =>
+ LDDI <= '1';
+ Write <= '1';
+ Set_Addr_To <= "11"; -- BA
+ when 5 =>
+ LDALU <= '1';
+ SaveP <= '1';
+ Write <= '1';
+ Set_Addr_To <= "11"; -- BA
+ when 6 =>
+ when others =>
+ end case;
+ else
+ LCycle <= "100";
+ if IR(7 downto 6) /= "10" then
+ LDA <= '1';
+ end if;
+ case to_integer(unsigned(MCycle)) is
+ when 0 =>
+ when 1 =>
+ Jump <= "01";
+ LDBAL <= '1';
+ when 2 =>
+ Jump <= "01";
+ -- mikej
+ -- special case 0xBE which uses Y reg as index!!
+ if (IR = "10111110") then
+ Set_BusA_To <= "011"; -- Y
+ else
+ Set_BusA_To <= "010"; -- X
+ end if;
+ BAAdd <= "10"; -- BA Add
+ LDBAH <= '1';
+ Set_Addr_To <= "11"; -- BA
+ when 3 =>
+ BAAdd <= "11"; -- BA adj
+ if IR(7 downto 5) = "100" then
+ Write <= '1';
+ else
+ BreakAtNA <= '1';
+ end if;
+ Set_Addr_To <= "11"; -- BA
+ when 4 =>
+ when others =>
+ end case;
+ end if;
+ --}}}
+ when others =>
+ end case;
+ end process;
+
+ process (IR, MCycle)
+ begin
+ -- ORA, AND, EOR, ADC, NOP, LD, CMP, SBC
+ -- ASL, ROL, LSR, ROR, BIT, LD, DEC, INC
+ case IR(1 downto 0) is
+ when "00" =>
+ --{{{
+ case IR(4 downto 2) is
+ when "000" | "001" | "011" =>
+ case IR(7 downto 5) is
+ when "110" | "111" =>
+ -- CP
+ ALU_Op <= "0110";
+ when "101" =>
+ -- LD
+ ALU_Op <= "0101";
+ when "001" =>
+ -- BIT
+ ALU_Op <= "1100";
+ when others =>
+ -- NOP/ST
+ ALU_Op <= "0100";
+ end case;
+ when "010" =>
+ case IR(7 downto 5) is
+ when "111" | "110" =>
+ -- IN
+ ALU_Op <= "1111";
+ when "100" =>
+ -- DEY
+ ALU_Op <= "1110";
+ when others =>
+ -- LD
+ ALU_Op <= "1101";
+ end case;
+ when "110" =>
+ case IR(7 downto 5) is
+ when "100" =>
+ -- TYA
+ ALU_Op <= "1101";
+ when others =>
+ ALU_Op <= "----";
+ end case;
+ when others =>
+ case IR(7 downto 5) is
+ when "101" =>
+ -- LD
+ ALU_Op <= "1101";
+ when others =>
+ ALU_Op <= "0100";
+ end case;
+ end case;
+ --}}}
+ when "01" => -- OR
+ --{{{
+ ALU_Op(3) <= '0';
+ ALU_Op(2 downto 0) <= IR(7 downto 5);
+ --}}}
+ when "10" =>
+ --{{{
+ ALU_Op(3) <= '1';
+ ALU_Op(2 downto 0) <= IR(7 downto 5);
+ case IR(7 downto 5) is
+ when "000" =>
+ if IR(4 downto 2) = "110" then
+ -- INC
+ ALU_Op <= "1111";
+ end if;
+ when "001" =>
+ if IR(4 downto 2) = "110" then
+ -- DEC
+ ALU_Op <= "1110";
+ end if;
+ when "100" =>
+ if IR(4 downto 2) = "010" then
+ -- TXA
+ ALU_Op <= "0101";
+ else
+ ALU_Op <= "0100";
+ end if;
+ when others =>
+ end case;
+ --}}}
+ when others =>
+ --{{{
+ case IR(7 downto 5) is
+ when "100" =>
+ ALU_Op <= "0100";
+ when others =>
+ if MCycle = "000" then
+ ALU_Op(3) <= '0';
+ ALU_Op(2 downto 0) <= IR(7 downto 5);
+ else
+ ALU_Op(3) <= '1';
+ ALU_Op(2 downto 0) <= IR(7 downto 5);
+ end if;
+ end case;
+ --}}}
+ end case;
+ end process;
+
+end;
diff --git a/T65/T65_Pack.vhd b/T65/T65_Pack.vhd new file mode 100644 index 0000000..f8d603c --- /dev/null +++ b/T65/T65_Pack.vhd @@ -0,0 +1,117 @@ +-- ****
+-- T65(b) core. In an effort to merge and maintain bug fixes ....
+--
+--
+-- Ver 300 Bugfixes by ehenciak added
+-- MikeJ March 2005
+-- Latest version from www.fpgaarcade.com (original www.opencores.org)
+--
+-- ****
+--
+-- 65xx compatible microprocessor core
+--
+-- Version : 0246
+--
+-- Copyright (c) 2002 Daniel Wallner (jesus@opencores.org)
+--
+-- All rights reserved
+--
+-- Redistribution and use in source and synthezised forms, with or without
+-- modification, are permitted provided that the following conditions are met:
+--
+-- Redistributions of source code must retain the above copyright notice,
+-- this list of conditions and the following disclaimer.
+--
+-- Redistributions in synthesized form must reproduce the above copyright
+-- notice, this list of conditions and the following disclaimer in the
+-- documentation and/or other materials provided with the distribution.
+--
+-- Neither the name of the author nor the names of other contributors may
+-- be used to endorse or promote products derived from this software without
+-- specific prior written permission.
+--
+-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+-- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+-- THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+-- PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE
+-- LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+-- CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+-- SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+-- INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+-- CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+-- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+-- POSSIBILITY OF SUCH DAMAGE.
+--
+-- Please report bugs to the author, but before you do so, please
+-- make sure that this is not a derivative work and that
+-- you have the latest version of this file.
+--
+-- The latest version of this file can be found at:
+-- http://www.opencores.org/cvsweb.shtml/t65/
+--
+-- Limitations :
+--
+-- File history :
+--
+
+library IEEE;
+use IEEE.std_logic_1164.all;
+
+package T65_Pack is
+
+ constant Flag_C : integer := 0;
+ constant Flag_Z : integer := 1;
+ constant Flag_I : integer := 2;
+ constant Flag_D : integer := 3;
+ constant Flag_B : integer := 4;
+ constant Flag_1 : integer := 5;
+ constant Flag_V : integer := 6;
+ constant Flag_N : integer := 7;
+
+ component T65_MCode
+ port(
+ Mode : in std_logic_vector(1 downto 0); -- "00" => 6502, "01" => 65C02, "10" => 65816
+ IR : in std_logic_vector(7 downto 0);
+ MCycle : in std_logic_vector(2 downto 0);
+ P : in std_logic_vector(7 downto 0);
+ LCycle : out std_logic_vector(2 downto 0);
+ ALU_Op : out std_logic_vector(3 downto 0);
+ Set_BusA_To : out std_logic_vector(2 downto 0); -- DI,A,X,Y,S,P
+ Set_Addr_To : out std_logic_vector(1 downto 0); -- PC Adder,S,AD,BA
+ Write_Data : out std_logic_vector(2 downto 0); -- DL,A,X,Y,S,P,PCL,PCH
+ Jump : out std_logic_vector(1 downto 0); -- PC,++,DIDL,Rel
+ BAAdd : out std_logic_vector(1 downto 0); -- None,DB Inc,BA Add,BA Adj
+ BreakAtNA : out std_logic;
+ ADAdd : out std_logic;
+ AddY : out std_logic;
+ PCAdd : out std_logic;
+ Inc_S : out std_logic;
+ Dec_S : out std_logic;
+ LDA : out std_logic;
+ LDP : out std_logic;
+ LDX : out std_logic;
+ LDY : out std_logic;
+ LDS : out std_logic;
+ LDDI : out std_logic;
+ LDALU : out std_logic;
+ LDAD : out std_logic;
+ LDBAL : out std_logic;
+ LDBAH : out std_logic;
+ SaveP : out std_logic;
+ Write : out std_logic
+ );
+ end component;
+
+ component T65_ALU
+ port(
+ Mode : in std_logic_vector(1 downto 0); -- "00" => 6502, "01" => 65C02, "10" => 65C816
+ Op : in std_logic_vector(3 downto 0);
+ BusA : in std_logic_vector(7 downto 0);
+ BusB : in std_logic_vector(7 downto 0);
+ P_In : in std_logic_vector(7 downto 0);
+ P_Out : out std_logic_vector(7 downto 0);
+ Q : out std_logic_vector(7 downto 0)
+ );
+ end component;
+
+end;
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