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add new cpu

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Stefan 2016-01-06 14:26:55 +01:00
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-- ****
-- T65(b) core. In an effort to merge and maintain bug fixes ....
--
-- Ver 313 WoS January 2015
-- Fixed issue that NMI has to be first if issued the same time as a BRK instruction is latched in
-- Now all Lorenz CPU tests on FPGAARCADE C64 core (sources used: SVN version 1021) are OK! :D :D :D
-- This is just a starting point to go for optimizations and detailed fixes (the Lorenz test can't find)
--
-- Ver 312 WoS January 2015
-- Undoc opcode timing fixes for $B3 (LAX iy) and $BB (LAS ay)
-- Added comments in MCode section to find handling of individual opcodes more easily
-- All "basic" Lorenz instruction test (individual functional checks, CPUTIMING check) work now with
-- actual FPGAARCADE C64 core (sources used: SVN version 1021).
--
-- Ver 305, 306, 307, 308, 309, 310, 311 WoS January 2015
-- Undoc opcode fixes (now all Lorenz test on instruction functionality working, except timing issues on $B3 and $BB):
-- SAX opcode
-- SHA opcode
-- SHX opcode
-- SHY opcode
-- SHS opcode
-- LAS opcode
-- alternate SBC opcode
-- fixed NOP with immediate param (caused Lorenz trap test to fail)
-- IRQ and NMI timing fixes (in conjuction with branches)
--
-- Ver 304 WoS December 2014
-- Undoc opcode fixes:
-- ARR opcode
-- ANE/XAA opcode
-- Corrected issue with NMI/IRQ prio (when asserted the same time)
--
-- Ver 303 ost(ML) July 2014
-- (Sorry for some scratchpad comments that may make little sense)
-- Mods and some 6502 undocumented instructions.
-- Not correct opcodes acc. to Lorenz tests (incomplete list):
-- NOPN (nop)
-- NOPZX (nop + byte 172)
-- NOPAX (nop + word da ... da: byte 0)
-- ASOZ (byte $07 + byte 172)
--
-- Ver 303,302 WoS April 2014
-- Bugfixes for NMI from foft
-- Bugfix for BRK command (and its special flag)
--
-- Ver 300,301 WoS January 2014
-- More merging
-- Bugfixes by ehenciak added, started tidyup *bust*
--
-- MikeJ March 2005
-- Latest version from www.fpgaarcade.com (original www.opencores.org)
-- ****
--
-- 65xx compatible microprocessor core
--
-- FPGAARCADE SVN: $Id: T65.vhd 1347 2015-05-27 20:07:34Z wolfgang.scherr $
--
-- Copyright (c) 2002...2015
-- Daniel Wallner (jesus <at> opencores <dot> org)
-- Mike Johnson (mikej <at> fpgaarcade <dot> com)
-- Wolfgang Scherr (WoS <at> pin4 <dot> at>
-- Morten Leikvoll ()
--
-- 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(s), 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.
--
-- ----- IMPORTANT NOTES -----
--
-- Limitations:
-- 65C02 and 65C816 modes are incomplete (and definitely untested after all 6502 undoc fixes)
-- 65C02 supported : inc, dec, phx, plx, phy, ply
-- 65D02 missing : bra, ora, lda, cmp, sbc, tsb*2, trb*2, stz*2, bit*2, wai, stp, jmp, bbr*8, bbs*8
-- Some interface signals behave incorrect
-- NMI interrupt handling not nice, needs further rework (to cycle-based encoding).
--
-- Usage:
-- The enable signal allows clock gating / throttling without using the ready signal.
-- Set it to constant '1' when using the Clk input as the CPU clock directly.
--
-- TAKE CARE you route the DO signal back to the DI signal while R_W_n='0',
-- otherwise some undocumented opcodes won't work correctly.
-- EXAMPLE:
-- CPU : entity work.T65
-- port map (
-- R_W_n => cpu_rwn_s,
-- [....all other ports....]
-- DI => cpu_din_s,
-- DO => cpu_dout_s
-- );
-- cpu_din_s <= cpu_dout_s when cpu_rwn_s='0' else
-- [....other sources from peripherals and memories...]
--
-- ----- IMPORTANT NOTES -----
--
library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.numeric_std.all;
use work.T65_Pack.all;
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);
DEBUG : out T_t65_dbg
);
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 PwithB : std_logic_vector(7 downto 0);--ML:New way to push P with correct B state to stack
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 : T_ALU_Op;
signal Write_Data_r : T_Write_Data;
signal Set_Addr_To_r : T_Set_Addr_To;
signal PCAdder : unsigned(8 downto 0);
signal RstCycle : std_logic;
signal IRQCycle : std_logic;
signal NMICycle : 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 BusB_r : 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 : T_ALU_Op;
signal Set_BusA_To : T_Set_BusA_To;
signal Set_Addr_To : T_Set_Addr_To;
signal Write_Data : T_Write_Data;
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 Res_n_i : std_logic;
signal Res_n_d : std_logic;
signal really_rdy : std_logic;
signal WRn_i : std_logic;
signal NMI_entered : std_logic;
begin
-- gate Rdy with read/write to make an "OK, it's really OK to stop the processor
really_rdy <= Rdy or not(WRn_i);
Sync <= '1' when MCycle = "000" else '0';
EF <= EF_i;
MF <= MF_i;
XF <= XF_i;
R_W_n <= WRn_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 /= Set_Addr_To_PBR else '0';
VPA <= '1' when Jump(1) = '0' else '0';
-- debugging signals
DEBUG.I <= IR;
DEBUG.A <= ABC(7 downto 0);
DEBUG.X <= X(7 downto 0);
DEBUG.Y <= Y(7 downto 0);
DEBUG.S <= std_logic_vector(S(7 downto 0));
DEBUG.P <= P;
mcode : entity work.T65_MCode
port map(
--inputs
Mode => Mode_r,
IR => IR,
MCycle => MCycle,
P => P,
--outputs
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 : entity work.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
);
-- the 65xx design requires at least two clock cycles before
-- starting its reset sequence (according to datasheet)
process (Res_n_i, Clk)
begin
if Res_n = '0' then
Res_n_i <= '0';
Res_n_d <= '0';
elsif Clk'event and Clk = '1' then
Res_n_i <= Res_n_d;
Res_n_d <= '1';
end if;
end process;
process (Res_n_i, Clk)
begin
if Res_n_i = '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 <= ALU_OP_BIT;
Write_Data_r <= Write_Data_DL;
Set_Addr_To_r <= Set_Addr_To_PBR;
WRn_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
WRn_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;
if LDS = '1' then -- LAS won't work properly if not limited to machine cycle 0
S(7 downto 0) <= unsigned(ALU_Q);
end if;
end if;
ALU_Op_r <= ALU_Op;
Write_Data_r <= Write_Data;
if Break = '1' then
Set_Addr_To_r <= Set_Addr_To_PBR;
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 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 (Res_n_i, Clk)
variable tmpP:std_logic_vector(7 downto 0);--Lets try to handle loading P at mcycle=0 and set/clk flags at same cycle
begin
if Res_n_i = '0' then
P <= x"00"; -- ensure we have nothing set on reset
elsif Clk'event and Clk = '1' then
tmpP:=P;
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
tmpP:=P_Out;
end if;
end if;
if SaveP = '1' then
tmpP:=P_Out;
end if;
if LDP = '1' then
tmpP:=ALU_Q;
end if;
if IR(4 downto 0) = "11000" then
case IR(7 downto 5) is
when "000" =>--0x18(clc)
tmpP(Flag_C) := '0';
when "001" =>--0x38(sec)
tmpP(Flag_C) := '1';
when "010" =>--0x58(cli)
tmpP(Flag_I) := '0';
when "011" =>--0x78(sei)
tmpP(Flag_I) := '1';
when "101" =>--0xb8(clv)
tmpP(Flag_V) := '0';
when "110" =>--0xd8(cld)
tmpP(Flag_D) := '0';
when "111" =>--0xf8(sed)
tmpP(Flag_D) := '1';
when others =>
end case;
end if;
tmpP(Flag_B) := '1';
if IR = "00000000" and MCycle = "100" and RstCycle = '0' then
--This should happen after P has been pushed to stack
tmpP(Flag_I) := '1';
end if;
if SO_n_o = '1' and SO_n = '0' then
tmpP(Flag_V) := '1';
end if;
if RstCycle = '1' then
tmpP(Flag_I) := '0';
tmpP(Flag_D) := '0';
end if;
tmpP(Flag_1) := '1';
P<=tmpP;--new way
SO_n_o <= SO_n;
if IR(4 downto 0)/="10000" or Jump/="01" then -- delay interrupts during branches (checked with Lorenz test and real 6510), not best way yet, though - but works...
IRQ_n_o <= IRQ_n;
end if;
end if;
-- detect nmi even if not rdy
if IR(4 downto 0)/="10000" or Jump/="01" then -- delay interrupts during branches (checked with Lorenz test and real 6510) not best way yet, though - but works...
NMI_n_o <= NMI_n;
end if;
end if;
end if;
end process;
---------------------------------------------------------------------------
--
-- Buses
--
---------------------------------------------------------------------------
process (Res_n_i, Clk)
begin
if Res_n_i = '0' then
BusA_r <= (others => '0');
BusB <= (others => '0');
BusB_r <= (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
NMI_entered <= '0';
if (really_rdy = '1') then
BusA_r <= BusA;
BusB <= DI;
-- not really nice, but no better way found yet !
if Set_Addr_To_r = Set_Addr_To_PBR or Set_Addr_To_r = Set_Addr_To_ZPG then
BusB_r <= std_logic_vector(unsigned(DI(7 downto 0)) + 1); -- required for SHA
end if;
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;
-- modified to use Y register as well
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' or (NMIAct = '1' and MCycle="100") or NMI_entered='1' then
BAL(2 downto 0) <= "010";
if MCycle="100" then
NMI_entered <= '1';
end if;
else
BAL(2 downto 0) <= "110";
end if;
if Set_addr_To_r = Set_Addr_To_BA 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 Set_BusA_To_DI,
ABC(7 downto 0) when Set_BusA_To_ABC,
X(7 downto 0) when Set_BusA_To_X,
Y(7 downto 0) when Set_BusA_To_Y,
std_logic_vector(S(7 downto 0)) when Set_BusA_To_S,
P when Set_BusA_To_P,
ABC(7 downto 0) and DI when Set_BusA_To_DA,
(ABC(7 downto 0) or x"ee") and DI when Set_BusA_To_DAO,--ee for OAL instruction. constant may be different on other platforms.TODO:Move to generics
(ABC(7 downto 0) or x"ee") and DI and X(7 downto 0) when Set_BusA_To_DAX,--XAA, ee for OAL instruction. constant may be different on other platforms.TODO:Move to generics
ABC(7 downto 0) and X(7 downto 0) when Set_BusA_To_AAX,--SAX, SHA
(others => '-') when Set_BusA_To_DONTCARE;--Can probably remove this
with Set_Addr_To_r select
A <=
"0000000000000001" & std_logic_vector(S(7 downto 0)) when Set_Addr_To_SP,
DBR & "00000000" & AD when Set_Addr_To_ZPG,
"00000000" & BAH & BAL(7 downto 0) when Set_Addr_To_BA,
PBR & std_logic_vector(PC(15 downto 8)) & std_logic_vector(PCAdder(7 downto 0)) when Set_Addr_To_PBR;
-- This is the P that gets pushed on stack with correct B flag. I'm not sure if NMI also clears B, but I guess it does.
PwithB<=(P and x"ef") when (IRQCycle='1' or NMICycle='1') else P;
with Write_Data_r select
DO <=
DL when Write_Data_DL,
ABC(7 downto 0) when Write_Data_ABC,
X(7 downto 0) when Write_Data_X,
Y(7 downto 0) when Write_Data_Y,
std_logic_vector(S(7 downto 0)) when Write_Data_S,
PwithB when Write_Data_P,
std_logic_vector(PC(7 downto 0)) when Write_Data_PCL,
std_logic_vector(PC(15 downto 8)) when Write_Data_PCH,
ABC(7 downto 0) and X(7 downto 0) when Write_Data_AX,
ABC(7 downto 0) and X(7 downto 0) and BusB_r(7 downto 0) when Write_Data_AXB, -- no better way found yet...
X(7 downto 0) and BusB_r(7 downto 0) when Write_Data_XB, -- no better way found yet...
Y(7 downto 0) and BusB_r(7 downto 0) when Write_Data_YB, -- no better way found yet...
(others=>'-') when Write_Data_DONTCARE;--Can probably remove this
-------------------------------------------------------------------------
--
-- Main state machine
--
-------------------------------------------------------------------------
process (Res_n_i, Clk)
begin
if Res_n_i = '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' and IR/=x"00" then -- delay NMI further if we just executed a BRK
NMICycle <= '1';
NMIAct <= '0'; -- reset NMI edge detector if we start processing the NMI
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;
end if;
--detect NMI even if not rdy
if NMI_n_o = '1' and (NMI_n = '0' and (IR(4 downto 0)/="10000" or Jump/="01")) then -- branches have influence on NMI start (not best way yet, though - but works...)
NMIAct <= '1';
end if;
-- we entered NMI during BRK instruction
if NMI_entered='1' then
NMIAct <= '0';
end if;
end if;
end if;
end process;
end;