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-- ****
-- T80(b) core. In an effort to merge and maintain bug fixes ....
--
--
-- Ver 300 started tidyup
-- MikeJ March 2005
-- Latest version from www.fpgaarcade.com (original www.opencores.org)
--
-- ****
--
-- Z80 compatible microprocessor core
--
-- Version : 0242
--
-- Copyright (c) 2001-2002 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/t80/
--
-- Limitations :
--
-- File history :
--
-- 0208 : First complete release
--
-- 0211 : Fixed IM 1
--
-- 0214 : Fixed mostly flags, only the block instructions now fail the zex regression test
--
-- 0235 : Added IM 2 fix by Mike Johnson
--
-- 0238 : Added NoRead signal
--
-- 0238b: Fixed instruction timing for POP and DJNZ
--
-- 0240 : Added (IX/IY+d) states, removed op-codes from mode 2 and added all remaining mode 3 op-codes
-- 0240mj1 fix for HL inc/dec for INI, IND, INIR, INDR, OUTI, OUTD, OTIR, OTDR
--
-- 0242 : Fixed I/O instruction timing, cleanup
--
library IEEE;
use IEEE.std_logic_1164.all;
use IEEE.numeric_std.all;
use work.T80_Pack.all;
entity T80_MCode is
generic(
Mode : integer := 0;
Flag_C : integer := 0;
Flag_N : integer := 1;
Flag_P : integer := 2;
Flag_X : integer := 3;
Flag_H : integer := 4;
Flag_Y : integer := 5;
Flag_Z : integer := 6;
Flag_S : integer := 7
);
port(
IR : in std_logic_vector(7 downto 0);
ISet : in std_logic_vector(1 downto 0);
MCycle : in std_logic_vector(2 downto 0);
F : in std_logic_vector(7 downto 0);
NMICycle : in std_logic;
IntCycle : in std_logic;
MCycles : out std_logic_vector(2 downto 0);
TStates : out std_logic_vector(2 downto 0);
Prefix : out std_logic_vector(1 downto 0); -- None,BC,ED,DD/FD
Inc_PC : out std_logic;
Inc_WZ : out std_logic;
IncDec_16 : out std_logic_vector(3 downto 0); -- BC,DE,HL,SP 0 is inc
Read_To_Reg : out std_logic;
Read_To_Acc : out std_logic;
Set_BusA_To : out std_logic_vector(3 downto 0); -- B,C,D,E,H,L,DI/DB,A,SP(L),SP(M),0,F
Set_BusB_To : out std_logic_vector(3 downto 0); -- B,C,D,E,H,L,DI,A,SP(L),SP(M),1,F,PC(L),PC(M),0
ALU_Op : out std_logic_vector(3 downto 0);
-- ADD, ADC, SUB, SBC, AND, XOR, OR, CP, ROT, BIT, SET, RES, DAA, RLD, RRD, None
Save_ALU : out std_logic;
PreserveC : out std_logic;
Arith16 : out std_logic;
Set_Addr_To : out std_logic_vector(2 downto 0); -- aNone,aXY,aIOA,aSP,aBC,aDE,aZI
IORQ : out std_logic;
Jump : out std_logic;
JumpE : out std_logic;
JumpXY : out std_logic;
Call : out std_logic;
RstP : out std_logic;
LDZ : out std_logic;
LDW : out std_logic;
LDSPHL : out std_logic;
Special_LD : out std_logic_vector(2 downto 0); -- A,I;A,R;I,A;R,A;None
ExchangeDH : out std_logic;
ExchangeRp : out std_logic;
ExchangeAF : out std_logic;
ExchangeRS : out std_logic;
I_DJNZ : out std_logic;
I_CPL : out std_logic;
I_CCF : out std_logic;
I_SCF : out std_logic;
I_RETN : out std_logic;
I_BT : out std_logic;
I_BC : out std_logic;
I_BTR : out std_logic;
I_RLD : out std_logic;
I_RRD : out std_logic;
I_INRC : out std_logic;
SetDI : out std_logic;
SetEI : out std_logic;
IMode : out std_logic_vector(1 downto 0);
Halt : out std_logic;
NoRead : out std_logic;
Write : out std_logic
);
end T80_MCode;
architecture rtl of T80_MCode is
constant aNone : std_logic_vector(2 downto 0) := "111";
constant aBC : std_logic_vector(2 downto 0) := "000";
constant aDE : std_logic_vector(2 downto 0) := "001";
constant aXY : std_logic_vector(2 downto 0) := "010";
constant aIOA : std_logic_vector(2 downto 0) := "100";
constant aSP : std_logic_vector(2 downto 0) := "101";
constant aZI : std_logic_vector(2 downto 0) := "110";
function is_cc_true(
F : std_logic_vector(7 downto 0);
cc : bit_vector(2 downto 0)
) return boolean is
begin
if Mode = 3 then
case cc is
when "000" => return F(7) = '0'; -- NZ
when "001" => return F(7) = '1'; -- Z
when "010" => return F(4) = '0'; -- NC
when "011" => return F(4) = '1'; -- C
when "100" => return false;
when "101" => return false;
when "110" => return false;
when "111" => return false;
end case;
else
case cc is
when "000" => return F(6) = '0'; -- NZ
when "001" => return F(6) = '1'; -- Z
when "010" => return F(0) = '0'; -- NC
when "011" => return F(0) = '1'; -- C
when "100" => return F(2) = '0'; -- PO
when "101" => return F(2) = '1'; -- PE
when "110" => return F(7) = '0'; -- P
when "111" => return F(7) = '1'; -- M
end case;
end if;
end;
begin
process (IR, ISet, MCycle, F, NMICycle, IntCycle)
variable DDD : std_logic_vector(2 downto 0);
variable SSS : std_logic_vector(2 downto 0);
variable DPair : std_logic_vector(1 downto 0);
variable IRB : bit_vector(7 downto 0);
begin
DDD := IR(5 downto 3);
SSS := IR(2 downto 0);
DPair := IR(5 downto 4);
IRB := to_bitvector(IR);
MCycles <= "001";
if MCycle = "001" then
TStates <= "100";
else
TStates <= "011";
end if;
Prefix <= "00";
Inc_PC <= '0';
Inc_WZ <= '0';
IncDec_16 <= "0000";
Read_To_Acc <= '0';
Read_To_Reg <= '0';
Set_BusB_To <= "0000";
Set_BusA_To <= "0000";
ALU_Op <= "0" & IR(5 downto 3);
Save_ALU <= '0';
PreserveC <= '0';
Arith16 <= '0';
IORQ <= '0';
Set_Addr_To <= aNone;
Jump <= '0';
JumpE <= '0';
JumpXY <= '0';
Call <= '0';
RstP <= '0';
LDZ <= '0';
LDW <= '0';
LDSPHL <= '0';
Special_LD <= "000";
ExchangeDH <= '0';
ExchangeRp <= '0';
ExchangeAF <= '0';
ExchangeRS <= '0';
I_DJNZ <= '0';
I_CPL <= '0';
I_CCF <= '0';
I_SCF <= '0';
I_RETN <= '0';
I_BT <= '0';
I_BC <= '0';
I_BTR <= '0';
I_RLD <= '0';
I_RRD <= '0';
I_INRC <= '0';
SetDI <= '0';
SetEI <= '0';
IMode <= "11";
Halt <= '0';
NoRead <= '0';
Write <= '0';
case ISet is
when "00" =>
------------------------------------------------------------------------------
--
-- Unprefixed instructions
--
------------------------------------------------------------------------------
case IRB is
-- 8 BIT LOAD GROUP
when "01000000"|"01000001"|"01000010"|"01000011"|"01000100"|"01000101"|"01000111"
|"01001000"|"01001001"|"01001010"|"01001011"|"01001100"|"01001101"|"01001111"
|"01010000"|"01010001"|"01010010"|"01010011"|"01010100"|"01010101"|"01010111"
|"01011000"|"01011001"|"01011010"|"01011011"|"01011100"|"01011101"|"01011111"
|"01100000"|"01100001"|"01100010"|"01100011"|"01100100"|"01100101"|"01100111"
|"01101000"|"01101001"|"01101010"|"01101011"|"01101100"|"01101101"|"01101111"
|"01111000"|"01111001"|"01111010"|"01111011"|"01111100"|"01111101"|"01111111" =>
-- LD r,r'
Set_BusB_To(2 downto 0) <= SSS;
ExchangeRp <= '1';
Set_BusA_To(2 downto 0) <= DDD;
Read_To_Reg <= '1';
when "00000110"|"00001110"|"00010110"|"00011110"|"00100110"|"00101110"|"00111110" =>
-- LD r,n
MCycles <= "010";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
Set_BusA_To(2 downto 0) <= DDD;
Read_To_Reg <= '1';
when others => null;
end case;
when "01000110"|"01001110"|"01010110"|"01011110"|"01100110"|"01101110"|"01111110" =>
-- LD r,(HL)
MCycles <= "010";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aXY;
when 2 =>
Set_BusA_To(2 downto 0) <= DDD;
Read_To_Reg <= '1';
when others => null;
end case;
when "01110000"|"01110001"|"01110010"|"01110011"|"01110100"|"01110101"|"01110111" =>
-- LD (HL),r
MCycles <= "010";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aXY;
Set_BusB_To(2 downto 0) <= SSS;
Set_BusB_To(3) <= '0';
when 2 =>
Write <= '1';
when others => null;
end case;
when "00110110" =>
-- LD (HL),n
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
Set_Addr_To <= aXY;
Set_BusB_To(2 downto 0) <= SSS;
Set_BusB_To(3) <= '0';
when 3 =>
Write <= '1';
when others => null;
end case;
when "00001010" =>
-- LD A,(BC)
MCycles <= "010";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aBC;
when 2 =>
Read_To_Acc <= '1';
when others => null;
end case;
when "00011010" =>
-- LD A,(DE)
MCycles <= "010";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aDE;
when 2 =>
Read_To_Acc <= '1';
when others => null;
end case;
when "00111010" =>
if Mode = 3 then
-- LDD A,(HL)
MCycles <= "010";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aXY;
when 2 =>
Read_To_Acc <= '1';
IncDec_16 <= "1110";
when others => null;
end case;
else
-- LD A,(nn)
MCycles <= "100";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
LDZ <= '1';
when 3 =>
Set_Addr_To <= aZI;
Inc_PC <= '1';
when 4 =>
Read_To_Acc <= '1';
when others => null;
end case;
end if;
when "00000010" =>
-- LD (BC),A
MCycles <= "010";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aBC;
Set_BusB_To <= "0111";
when 2 =>
Write <= '1';
when others => null;
end case;
when "00010010" =>
-- LD (DE),A
MCycles <= "010";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aDE;
Set_BusB_To <= "0111";
when 2 =>
Write <= '1';
when others => null;
end case;
when "00110010" =>
if Mode = 3 then
-- LDD (HL),A
MCycles <= "010";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aXY;
Set_BusB_To <= "0111";
when 2 =>
Write <= '1';
IncDec_16 <= "1110";
when others => null;
end case;
else
-- LD (nn),A
MCycles <= "100";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
LDZ <= '1';
when 3 =>
Set_Addr_To <= aZI;
Inc_PC <= '1';
Set_BusB_To <= "0111";
when 4 =>
Write <= '1';
when others => null;
end case;
end if;
-- 16 BIT LOAD GROUP
when "00000001"|"00010001"|"00100001"|"00110001" =>
-- LD dd,nn
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
Read_To_Reg <= '1';
if DPAIR = "11" then
Set_BusA_To(3 downto 0) <= "1000";
else
Set_BusA_To(2 downto 1) <= DPAIR;
Set_BusA_To(0) <= '1';
end if;
when 3 =>
Inc_PC <= '1';
Read_To_Reg <= '1';
if DPAIR = "11" then
Set_BusA_To(3 downto 0) <= "1001";
else
Set_BusA_To(2 downto 1) <= DPAIR;
Set_BusA_To(0) <= '0';
end if;
when others => null;
end case;
when "00101010" =>
if Mode = 3 then
-- LDI A,(HL)
MCycles <= "010";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aXY;
when 2 =>
Read_To_Acc <= '1';
IncDec_16 <= "0110";
when others => null;
end case;
else
-- LD HL,(nn)
MCycles <= "101";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
LDZ <= '1';
when 3 =>
Set_Addr_To <= aZI;
Inc_PC <= '1';
LDW <= '1';
when 4 =>
Set_BusA_To(2 downto 0) <= "101"; -- L
Read_To_Reg <= '1';
Inc_WZ <= '1';
Set_Addr_To <= aZI;
when 5 =>
Set_BusA_To(2 downto 0) <= "100"; -- H
Read_To_Reg <= '1';
when others => null;
end case;
end if;
when "00100010" =>
if Mode = 3 then
-- LDI (HL),A
MCycles <= "010";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aXY;
Set_BusB_To <= "0111";
when 2 =>
Write <= '1';
IncDec_16 <= "0110";
when others => null;
end case;
else
-- LD (nn),HL
MCycles <= "101";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
LDZ <= '1';
when 3 =>
Set_Addr_To <= aZI;
Inc_PC <= '1';
LDW <= '1';
Set_BusB_To <= "0101"; -- L
when 4 =>
Inc_WZ <= '1';
Set_Addr_To <= aZI;
Write <= '1';
Set_BusB_To <= "0100"; -- H
when 5 =>
Write <= '1';
when others => null;
end case;
end if;
when "11111001" =>
-- LD SP,HL
TStates <= "110";
LDSPHL <= '1';
when "11000101"|"11010101"|"11100101"|"11110101" =>
-- PUSH qq
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 1 =>
TStates <= "101";
IncDec_16 <= "1111";
Set_Addr_TO <= aSP;
if DPAIR = "11" then
Set_BusB_To <= "0111";
else
Set_BusB_To(2 downto 1) <= DPAIR;
Set_BusB_To(0) <= '0';
Set_BusB_To(3) <= '0';
end if;
when 2 =>
IncDec_16 <= "1111";
Set_Addr_To <= aSP;
if DPAIR = "11" then
Set_BusB_To <= "1011";
else
Set_BusB_To(2 downto 1) <= DPAIR;
Set_BusB_To(0) <= '1';
Set_BusB_To(3) <= '0';
end if;
Write <= '1';
when 3 =>
Write <= '1';
when others => null;
end case;
when "11000001"|"11010001"|"11100001"|"11110001" =>
-- POP qq
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aSP;
when 2 =>
IncDec_16 <= "0111";
Set_Addr_To <= aSP;
Read_To_Reg <= '1';
if DPAIR = "11" then
Set_BusA_To(3 downto 0) <= "1011";
else
Set_BusA_To(2 downto 1) <= DPAIR;
Set_BusA_To(0) <= '1';
end if;
when 3 =>
IncDec_16 <= "0111";
Read_To_Reg <= '1';
if DPAIR = "11" then
Set_BusA_To(3 downto 0) <= "0111";
else
Set_BusA_To(2 downto 1) <= DPAIR;
Set_BusA_To(0) <= '0';
end if;
when others => null;
end case;
-- EXCHANGE, BLOCK TRANSFER AND SEARCH GROUP
when "11101011" =>
if Mode /= 3 then
-- EX DE,HL
ExchangeDH <= '1';
end if;
when "00001000" =>
if Mode = 3 then
-- LD (nn),SP
MCycles <= "101";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
LDZ <= '1';
when 3 =>
Set_Addr_To <= aZI;
Inc_PC <= '1';
LDW <= '1';
Set_BusB_To <= "1000";
when 4 =>
Inc_WZ <= '1';
Set_Addr_To <= aZI;
Write <= '1';
Set_BusB_To <= "1001";
when 5 =>
Write <= '1';
when others => null;
end case;
elsif Mode < 2 then
-- EX AF,AF'
ExchangeAF <= '1';
end if;
when "11011001" =>
if Mode = 3 then
-- RETI
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_TO <= aSP;
when 2 =>
IncDec_16 <= "0111";
Set_Addr_To <= aSP;
LDZ <= '1';
when 3 =>
Jump <= '1';
IncDec_16 <= "0111";
I_RETN <= '1';
SetEI <= '1';
when others => null;
end case;
elsif Mode < 2 then
-- EXX
ExchangeRS <= '1';
end if;
when "11100011" =>
if Mode /= 3 then
-- EX (SP),HL
MCycles <= "101";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aSP;
when 2 =>
Read_To_Reg <= '1';
Set_BusA_To <= "0101";
Set_BusB_To <= "0101";
Set_Addr_To <= aSP;
when 3 =>
IncDec_16 <= "0111";
Set_Addr_To <= aSP;
TStates <= "100";
Write <= '1';
when 4 =>
Read_To_Reg <= '1';
Set_BusA_To <= "0100";
Set_BusB_To <= "0100";
Set_Addr_To <= aSP;
when 5 =>
IncDec_16 <= "1111";
TStates <= "101";
Write <= '1';
when others => null;
end case;
end if;
-- 8 BIT ARITHMETIC AND LOGICAL GROUP
when "10000000"|"10000001"|"10000010"|"10000011"|"10000100"|"10000101"|"10000111"
|"10001000"|"10001001"|"10001010"|"10001011"|"10001100"|"10001101"|"10001111"
|"10010000"|"10010001"|"10010010"|"10010011"|"10010100"|"10010101"|"10010111"
|"10011000"|"10011001"|"10011010"|"10011011"|"10011100"|"10011101"|"10011111"
|"10100000"|"10100001"|"10100010"|"10100011"|"10100100"|"10100101"|"10100111"
|"10101000"|"10101001"|"10101010"|"10101011"|"10101100"|"10101101"|"10101111"
|"10110000"|"10110001"|"10110010"|"10110011"|"10110100"|"10110101"|"10110111"
|"10111000"|"10111001"|"10111010"|"10111011"|"10111100"|"10111101"|"10111111" =>
-- ADD A,r
-- ADC A,r
-- SUB A,r
-- SBC A,r
-- AND A,r
-- OR A,r
-- XOR A,r
-- CP A,r
Set_BusB_To(2 downto 0) <= SSS;
Set_BusA_To(2 downto 0) <= "111";
Read_To_Reg <= '1';
Save_ALU <= '1';
when "10000110"|"10001110"|"10010110"|"10011110"|"10100110"|"10101110"|"10110110"|"10111110" =>
-- ADD A,(HL)
-- ADC A,(HL)
-- SUB A,(HL)
-- SBC A,(HL)
-- AND A,(HL)
-- OR A,(HL)
-- XOR A,(HL)
-- CP A,(HL)
MCycles <= "010";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aXY;
when 2 =>
Read_To_Reg <= '1';
Save_ALU <= '1';
Set_BusB_To(2 downto 0) <= SSS;
Set_BusA_To(2 downto 0) <= "111";
when others => null;
end case;
when "11000110"|"11001110"|"11010110"|"11011110"|"11100110"|"11101110"|"11110110"|"11111110" =>
-- ADD A,n
-- ADC A,n
-- SUB A,n
-- SBC A,n
-- AND A,n
-- OR A,n
-- XOR A,n
-- CP A,n
MCycles <= "010";
if MCycle = "010" then
Inc_PC <= '1';
Read_To_Reg <= '1';
Save_ALU <= '1';
Set_BusB_To(2 downto 0) <= SSS;
Set_BusA_To(2 downto 0) <= "111";
end if;
when "00000100"|"00001100"|"00010100"|"00011100"|"00100100"|"00101100"|"00111100" =>
-- INC r
Set_BusB_To <= "1010";
Set_BusA_To(2 downto 0) <= DDD;
Read_To_Reg <= '1';
Save_ALU <= '1';
PreserveC <= '1';
ALU_Op <= "0000";
when "00110100" =>
-- INC (HL)
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aXY;
when 2 =>
TStates <= "100";
Set_Addr_To <= aXY;
Read_To_Reg <= '1';
Save_ALU <= '1';
PreserveC <= '1';
ALU_Op <= "0000";
Set_BusB_To <= "1010";
Set_BusA_To(2 downto 0) <= DDD;
when 3 =>
Write <= '1';
when others => null;
end case;
when "00000101"|"00001101"|"00010101"|"00011101"|"00100101"|"00101101"|"00111101" =>
-- DEC r
Set_BusB_To <= "1010";
Set_BusA_To(2 downto 0) <= DDD;
Read_To_Reg <= '1';
Save_ALU <= '1';
PreserveC <= '1';
ALU_Op <= "0010";
when "00110101" =>
-- DEC (HL)
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aXY;
when 2 =>
TStates <= "100";
Set_Addr_To <= aXY;
ALU_Op <= "0010";
Read_To_Reg <= '1';
Save_ALU <= '1';
PreserveC <= '1';
Set_BusB_To <= "1010";
Set_BusA_To(2 downto 0) <= DDD;
when 3 =>
Write <= '1';
when others => null;
end case;
-- GENERAL PURPOSE ARITHMETIC AND CPU CONTROL GROUPS
when "00100111" =>
-- DAA
Set_BusA_To(2 downto 0) <= "111";
Read_To_Reg <= '1';
ALU_Op <= "1100";
Save_ALU <= '1';
when "00101111" =>
-- CPL
I_CPL <= '1';
when "00111111" =>
-- CCF
I_CCF <= '1';
when "00110111" =>
-- SCF
I_SCF <= '1';
when "00000000" =>
if NMICycle = '1' then
-- NMI
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 1 =>
TStates <= "101";
IncDec_16 <= "1111";
Set_Addr_To <= aSP;
Set_BusB_To <= "1101";
when 2 =>
TStates <= "100";
Write <= '1';
IncDec_16 <= "1111";
Set_Addr_To <= aSP;
Set_BusB_To <= "1100";
when 3 =>
TStates <= "100";
Write <= '1';
when others => null;
end case;
elsif IntCycle = '1' then
-- INT (IM 2)
MCycles <= "101";
case to_integer(unsigned(MCycle)) is
when 1 =>
LDZ <= '1';
TStates <= "101";
IncDec_16 <= "1111";
Set_Addr_To <= aSP;
Set_BusB_To <= "1101";
when 2 =>
TStates <= "100";
Write <= '1';
IncDec_16 <= "1111";
Set_Addr_To <= aSP;
Set_BusB_To <= "1100";
when 3 =>
TStates <= "100";
Write <= '1';
when 4 =>
Inc_PC <= '1';
LDZ <= '1';
when 5 =>
Jump <= '1';
when others => null;
end case;
else
-- NOP
end if;
when "01110110" =>
-- HALT
Halt <= '1';
when "11110011" =>
-- DI
SetDI <= '1';
when "11111011" =>
-- EI
SetEI <= '1';
-- 16 BIT ARITHMETIC GROUP
when "00001001"|"00011001"|"00101001"|"00111001" =>
-- ADD HL,ss
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 2 =>
NoRead <= '1';
ALU_Op <= "0000";
Read_To_Reg <= '1';
Save_ALU <= '1';
Set_BusA_To(2 downto 0) <= "101";
case to_integer(unsigned(IR(5 downto 4))) is
when 0|1|2 =>
Set_BusB_To(2 downto 1) <= IR(5 downto 4);
Set_BusB_To(0) <= '1';
when others =>
Set_BusB_To <= "1000";
end case;
TStates <= "100";
Arith16 <= '1';
when 3 =>
NoRead <= '1';
Read_To_Reg <= '1';
Save_ALU <= '1';
ALU_Op <= "0001";
Set_BusA_To(2 downto 0) <= "100";
case to_integer(unsigned(IR(5 downto 4))) is
when 0|1|2 =>
Set_BusB_To(2 downto 1) <= IR(5 downto 4);
when others =>
Set_BusB_To <= "1001";
end case;
Arith16 <= '1';
when others =>
end case;
when "00000011"|"00010011"|"00100011"|"00110011" =>
-- INC ss
TStates <= "110";
IncDec_16(3 downto 2) <= "01";
IncDec_16(1 downto 0) <= DPair;
when "00001011"|"00011011"|"00101011"|"00111011" =>
-- DEC ss
TStates <= "110";
IncDec_16(3 downto 2) <= "11";
IncDec_16(1 downto 0) <= DPair;
-- ROTATE AND SHIFT GROUP
when "00000111"
-- RLCA
|"00010111"
-- RLA
|"00001111"
-- RRCA
|"00011111" =>
-- RRA
Set_BusA_To(2 downto 0) <= "111";
ALU_Op <= "1000";
Read_To_Reg <= '1';
Save_ALU <= '1';
-- JUMP GROUP
when "11000011" =>
-- JP nn
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
LDZ <= '1';
when 3 =>
Inc_PC <= '1';
Jump <= '1';
when others => null;
end case;
when "11000010"|"11001010"|"11010010"|"11011010"|"11100010"|"11101010"|"11110010"|"11111010" =>
if IR(5) = '1' and Mode = 3 then
case IRB(4 downto 3) is
when "00" =>
-- LD ($FF00+C),A
MCycles <= "010";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aBC;
Set_BusB_To <= "0111";
when 2 =>
Write <= '1';
IORQ <= '1';
when others =>
end case;
when "01" =>
-- LD (nn),A
MCycles <= "100";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
LDZ <= '1';
when 3 =>
Set_Addr_To <= aZI;
Inc_PC <= '1';
Set_BusB_To <= "0111";
when 4 =>
Write <= '1';
when others => null;
end case;
when "10" =>
-- LD A,($FF00+C)
MCycles <= "010";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aBC;
when 2 =>
Read_To_Acc <= '1';
IORQ <= '1';
when others =>
end case;
when "11" =>
-- LD A,(nn)
MCycles <= "100";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
LDZ <= '1';
when 3 =>
Set_Addr_To <= aZI;
Inc_PC <= '1';
when 4 =>
Read_To_Acc <= '1';
when others => null;
end case;
end case;
else
-- JP cc,nn
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
LDZ <= '1';
when 3 =>
Inc_PC <= '1';
if is_cc_true(F, to_bitvector(IR(5 downto 3))) then
Jump <= '1';
end if;
when others => null;
end case;
end if;
when "00011000" =>
if Mode /= 2 then
-- JR e
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
when 3 =>
NoRead <= '1';
JumpE <= '1';
TStates <= "101";
when others => null;
end case;
end if;
when "00111000" =>
if Mode /= 2 then
-- JR C,e
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
if F(Flag_C) = '0' then
MCycles <= "010";
end if;
when 3 =>
NoRead <= '1';
JumpE <= '1';
TStates <= "101";
when others => null;
end case;
end if;
when "00110000" =>
if Mode /= 2 then
-- JR NC,e
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
if F(Flag_C) = '1' then
MCycles <= "010";
end if;
when 3 =>
NoRead <= '1';
JumpE <= '1';
TStates <= "101";
when others => null;
end case;
end if;
when "00101000" =>
if Mode /= 2 then
-- JR Z,e
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
if F(Flag_Z) = '0' then
MCycles <= "010";
end if;
when 3 =>
NoRead <= '1';
JumpE <= '1';
TStates <= "101";
when others => null;
end case;
end if;
when "00100000" =>
if Mode /= 2 then
-- JR NZ,e
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
if F(Flag_Z) = '1' then
MCycles <= "010";
end if;
when 3 =>
NoRead <= '1';
JumpE <= '1';
TStates <= "101";
when others => null;
end case;
end if;
when "11101001" =>
-- JP (HL)
JumpXY <= '1';
when "00010000" =>
if Mode = 3 then
I_DJNZ <= '1';
elsif Mode < 2 then
-- DJNZ,e
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 1 =>
TStates <= "101";
I_DJNZ <= '1';
Set_BusB_To <= "1010";
Set_BusA_To(2 downto 0) <= "000";
Read_To_Reg <= '1';
Save_ALU <= '1';
ALU_Op <= "0010";
when 2 =>
I_DJNZ <= '1';
Inc_PC <= '1';
when 3 =>
NoRead <= '1';
JumpE <= '1';
TStates <= "101";
when others => null;
end case;
end if;
-- CALL AND RETURN GROUP
when "11001101" =>
-- CALL nn
MCycles <= "101";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
LDZ <= '1';
when 3 =>
IncDec_16 <= "1111";
Inc_PC <= '1';
TStates <= "100";
Set_Addr_To <= aSP;
LDW <= '1';
Set_BusB_To <= "1101";
when 4 =>
Write <= '1';
IncDec_16 <= "1111";
Set_Addr_To <= aSP;
Set_BusB_To <= "1100";
when 5 =>
Write <= '1';
Call <= '1';
when others => null;
end case;
when "11000100"|"11001100"|"11010100"|"11011100"|"11100100"|"11101100"|"11110100"|"11111100" =>
if IR(5) = '0' or Mode /= 3 then
-- CALL cc,nn
MCycles <= "101";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
LDZ <= '1';
when 3 =>
Inc_PC <= '1';
LDW <= '1';
if is_cc_true(F, to_bitvector(IR(5 downto 3))) then
IncDec_16 <= "1111";
Set_Addr_TO <= aSP;
TStates <= "100";
Set_BusB_To <= "1101";
else
MCycles <= "011";
end if;
when 4 =>
Write <= '1';
IncDec_16 <= "1111";
Set_Addr_To <= aSP;
Set_BusB_To <= "1100";
when 5 =>
Write <= '1';
Call <= '1';
when others => null;
end case;
end if;
when "11001001" =>
-- RET
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 1 =>
TStates <= "101";
Set_Addr_TO <= aSP;
when 2 =>
IncDec_16 <= "0111";
Set_Addr_To <= aSP;
LDZ <= '1';
when 3 =>
Jump <= '1';
IncDec_16 <= "0111";
when others => null;
end case;
when "11000000"|"11001000"|"11010000"|"11011000"|"11100000"|"11101000"|"11110000"|"11111000" =>
if IR(5) = '1' and Mode = 3 then
case IRB(4 downto 3) is
when "00" =>
-- LD ($FF00+nn),A
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
Set_Addr_To <= aIOA;
Set_BusB_To <= "0111";
when 3 =>
Write <= '1';
when others => null;
end case;
when "01" =>
-- ADD SP,n
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 2 =>
ALU_Op <= "0000";
Inc_PC <= '1';
Read_To_Reg <= '1';
Save_ALU <= '1';
Set_BusA_To <= "1000";
Set_BusB_To <= "0110";
when 3 =>
NoRead <= '1';
Read_To_Reg <= '1';
Save_ALU <= '1';
ALU_Op <= "0001";
Set_BusA_To <= "1001";
Set_BusB_To <= "1110"; -- Incorrect unsigned !!!!!!!!!!!!!!!!!!!!!
when others =>
end case;
when "10" =>
-- LD A,($FF00+nn)
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
Set_Addr_To <= aIOA;
when 3 =>
Read_To_Acc <= '1';
when others => null;
end case;
when "11" =>
-- LD HL,SP+n -- Not correct !!!!!!!!!!!!!!!!!!!
MCycles <= "101";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
LDZ <= '1';
when 3 =>
Set_Addr_To <= aZI;
Inc_PC <= '1';
LDW <= '1';
when 4 =>
Set_BusA_To(2 downto 0) <= "101"; -- L
Read_To_Reg <= '1';
Inc_WZ <= '1';
Set_Addr_To <= aZI;
when 5 =>
Set_BusA_To(2 downto 0) <= "100"; -- H
Read_To_Reg <= '1';
when others => null;
end case;
end case;
else
-- RET cc
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 1 =>
if is_cc_true(F, to_bitvector(IR(5 downto 3))) then
Set_Addr_TO <= aSP;
else
MCycles <= "001";
end if;
TStates <= "101";
when 2 =>
IncDec_16 <= "0111";
Set_Addr_To <= aSP;
LDZ <= '1';
when 3 =>
Jump <= '1';
IncDec_16 <= "0111";
when others => null;
end case;
end if;
when "11000111"|"11001111"|"11010111"|"11011111"|"11100111"|"11101111"|"11110111"|"11111111" =>
-- RST p
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 1 =>
TStates <= "101";
IncDec_16 <= "1111";
Set_Addr_To <= aSP;
Set_BusB_To <= "1101";
when 2 =>
Write <= '1';
IncDec_16 <= "1111";
Set_Addr_To <= aSP;
Set_BusB_To <= "1100";
when 3 =>
Write <= '1';
RstP <= '1';
when others => null;
end case;
-- INPUT AND OUTPUT GROUP
when "11011011" =>
if Mode /= 3 then
-- IN A,(n)
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
Set_Addr_To <= aIOA;
when 3 =>
Read_To_Acc <= '1';
IORQ <= '1';
when others => null;
end case;
end if;
when "11010011" =>
if Mode /= 3 then
-- OUT (n),A
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
Set_Addr_To <= aIOA;
Set_BusB_To <= "0111";
when 3 =>
Write <= '1';
IORQ <= '1';
when others => null;
end case;
end if;
------------------------------------------------------------------------------
------------------------------------------------------------------------------
-- MULTIBYTE INSTRUCTIONS
------------------------------------------------------------------------------
------------------------------------------------------------------------------
when "11001011" =>
if Mode /= 2 then
Prefix <= "01";
end if;
when "11101101" =>
if Mode < 2 then
Prefix <= "10";
end if;
when "11011101"|"11111101" =>
if Mode < 2 then
Prefix <= "11";
end if;
end case;
when "01" =>
------------------------------------------------------------------------------
--
-- CB prefixed instructions
--
------------------------------------------------------------------------------
Set_BusA_To(2 downto 0) <= IR(2 downto 0);
Set_BusB_To(2 downto 0) <= IR(2 downto 0);
case IRB is
when "00000000"|"00000001"|"00000010"|"00000011"|"00000100"|"00000101"|"00000111"
|"00010000"|"00010001"|"00010010"|"00010011"|"00010100"|"00010101"|"00010111"
|"00001000"|"00001001"|"00001010"|"00001011"|"00001100"|"00001101"|"00001111"
|"00011000"|"00011001"|"00011010"|"00011011"|"00011100"|"00011101"|"00011111"
|"00100000"|"00100001"|"00100010"|"00100011"|"00100100"|"00100101"|"00100111"
|"00101000"|"00101001"|"00101010"|"00101011"|"00101100"|"00101101"|"00101111"
|"00110000"|"00110001"|"00110010"|"00110011"|"00110100"|"00110101"|"00110111"
|"00111000"|"00111001"|"00111010"|"00111011"|"00111100"|"00111101"|"00111111" =>
-- RLC r
-- RL r
-- RRC r
-- RR r
-- SLA r
-- SRA r
-- SRL r
-- SLL r (Undocumented) / SWAP r
if MCycle = "001" then
ALU_Op <= "1000";
Read_To_Reg <= '1';
Save_ALU <= '1';
end if;
when "00000110"|"00010110"|"00001110"|"00011110"|"00101110"|"00111110"|"00100110"|"00110110" =>
-- RLC (HL)
-- RL (HL)
-- RRC (HL)
-- RR (HL)
-- SRA (HL)
-- SRL (HL)
-- SLA (HL)
-- SLL (HL) (Undocumented) / SWAP (HL)
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 1 | 7 =>
Set_Addr_To <= aXY;
when 2 =>
ALU_Op <= "1000";
Read_To_Reg <= '1';
Save_ALU <= '1';
Set_Addr_To <= aXY;
TStates <= "100";
when 3 =>
Write <= '1';
when others =>
end case;
when "01000000"|"01000001"|"01000010"|"01000011"|"01000100"|"01000101"|"01000111"
|"01001000"|"01001001"|"01001010"|"01001011"|"01001100"|"01001101"|"01001111"
|"01010000"|"01010001"|"01010010"|"01010011"|"01010100"|"01010101"|"01010111"
|"01011000"|"01011001"|"01011010"|"01011011"|"01011100"|"01011101"|"01011111"
|"01100000"|"01100001"|"01100010"|"01100011"|"01100100"|"01100101"|"01100111"
|"01101000"|"01101001"|"01101010"|"01101011"|"01101100"|"01101101"|"01101111"
|"01110000"|"01110001"|"01110010"|"01110011"|"01110100"|"01110101"|"01110111"
|"01111000"|"01111001"|"01111010"|"01111011"|"01111100"|"01111101"|"01111111" =>
-- BIT b,r
if MCycle = "001" then
Set_BusB_To(2 downto 0) <= IR(2 downto 0);
ALU_Op <= "1001";
end if;
when "01000110"|"01001110"|"01010110"|"01011110"|"01100110"|"01101110"|"01110110"|"01111110" =>
-- BIT b,(HL)
MCycles <= "010";
case to_integer(unsigned(MCycle)) is
when 1 | 7=>
Set_Addr_To <= aXY;
when 2 =>
ALU_Op <= "1001";
TStates <= "100";
when others => null;
end case;
when "11000000"|"11000001"|"11000010"|"11000011"|"11000100"|"11000101"|"11000111"
|"11001000"|"11001001"|"11001010"|"11001011"|"11001100"|"11001101"|"11001111"
|"11010000"|"11010001"|"11010010"|"11010011"|"11010100"|"11010101"|"11010111"
|"11011000"|"11011001"|"11011010"|"11011011"|"11011100"|"11011101"|"11011111"
|"11100000"|"11100001"|"11100010"|"11100011"|"11100100"|"11100101"|"11100111"
|"11101000"|"11101001"|"11101010"|"11101011"|"11101100"|"11101101"|"11101111"
|"11110000"|"11110001"|"11110010"|"11110011"|"11110100"|"11110101"|"11110111"
|"11111000"|"11111001"|"11111010"|"11111011"|"11111100"|"11111101"|"11111111" =>
-- SET b,r
if MCycle = "001" then
ALU_Op <= "1010";
Read_To_Reg <= '1';
Save_ALU <= '1';
end if;
when "11000110"|"11001110"|"11010110"|"11011110"|"11100110"|"11101110"|"11110110"|"11111110" =>
-- SET b,(HL)
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 1 | 7=>
Set_Addr_To <= aXY;
when 2 =>
ALU_Op <= "1010";
Read_To_Reg <= '1';
Save_ALU <= '1';
Set_Addr_To <= aXY;
TStates <= "100";
when 3 =>
Write <= '1';
when others => null;
end case;
when "10000000"|"10000001"|"10000010"|"10000011"|"10000100"|"10000101"|"10000111"
|"10001000"|"10001001"|"10001010"|"10001011"|"10001100"|"10001101"|"10001111"
|"10010000"|"10010001"|"10010010"|"10010011"|"10010100"|"10010101"|"10010111"
|"10011000"|"10011001"|"10011010"|"10011011"|"10011100"|"10011101"|"10011111"
|"10100000"|"10100001"|"10100010"|"10100011"|"10100100"|"10100101"|"10100111"
|"10101000"|"10101001"|"10101010"|"10101011"|"10101100"|"10101101"|"10101111"
|"10110000"|"10110001"|"10110010"|"10110011"|"10110100"|"10110101"|"10110111"
|"10111000"|"10111001"|"10111010"|"10111011"|"10111100"|"10111101"|"10111111" =>
-- RES b,r
if MCycle = "001" then
ALU_Op <= "1011";
Read_To_Reg <= '1';
Save_ALU <= '1';
end if;
when "10000110"|"10001110"|"10010110"|"10011110"|"10100110"|"10101110"|"10110110"|"10111110" =>
-- RES b,(HL)
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 1 | 7 =>
Set_Addr_To <= aXY;
when 2 =>
ALU_Op <= "1011";
Read_To_Reg <= '1';
Save_ALU <= '1';
Set_Addr_To <= aXY;
TStates <= "100";
when 3 =>
Write <= '1';
when others => null;
end case;
end case;
when others =>
------------------------------------------------------------------------------
--
-- ED prefixed instructions
--
------------------------------------------------------------------------------
case IRB is
when "00000000"|"00000001"|"00000010"|"00000011"|"00000100"|"00000101"|"00000110"|"00000111"
|"00001000"|"00001001"|"00001010"|"00001011"|"00001100"|"00001101"|"00001110"|"00001111"
|"00010000"|"00010001"|"00010010"|"00010011"|"00010100"|"00010101"|"00010110"|"00010111"
|"00011000"|"00011001"|"00011010"|"00011011"|"00011100"|"00011101"|"00011110"|"00011111"
|"00100000"|"00100001"|"00100010"|"00100011"|"00100100"|"00100101"|"00100110"|"00100111"
|"00101000"|"00101001"|"00101010"|"00101011"|"00101100"|"00101101"|"00101110"|"00101111"
|"00110000"|"00110001"|"00110010"|"00110011"|"00110100"|"00110101"|"00110110"|"00110111"
|"00111000"|"00111001"|"00111010"|"00111011"|"00111100"|"00111101"|"00111110"|"00111111"
|"10000000"|"10000001"|"10000010"|"10000011"|"10000100"|"10000101"|"10000110"|"10000111"
|"10001000"|"10001001"|"10001010"|"10001011"|"10001100"|"10001101"|"10001110"|"10001111"
|"10010000"|"10010001"|"10010010"|"10010011"|"10010100"|"10010101"|"10010110"|"10010111"
|"10011000"|"10011001"|"10011010"|"10011011"|"10011100"|"10011101"|"10011110"|"10011111"
| "10100100"|"10100101"|"10100110"|"10100111"
| "10101100"|"10101101"|"10101110"|"10101111"
| "10110100"|"10110101"|"10110110"|"10110111"
| "10111100"|"10111101"|"10111110"|"10111111"
|"11000000"|"11000001"|"11000010"|"11000011"|"11000100"|"11000101"|"11000110"|"11000111"
|"11001000"|"11001001"|"11001010"|"11001011"|"11001100"|"11001101"|"11001110"|"11001111"
|"11010000"|"11010001"|"11010010"|"11010011"|"11010100"|"11010101"|"11010110"|"11010111"
|"11011000"|"11011001"|"11011010"|"11011011"|"11011100"|"11011101"|"11011110"|"11011111"
|"11100000"|"11100001"|"11100010"|"11100011"|"11100100"|"11100101"|"11100110"|"11100111"
|"11101000"|"11101001"|"11101010"|"11101011"|"11101100"|"11101101"|"11101110"|"11101111"
|"11110000"|"11110001"|"11110010"|"11110011"|"11110100"|"11110101"|"11110110"|"11110111"
|"11111000"|"11111001"|"11111010"|"11111011"|"11111100"|"11111101"|"11111110"|"11111111" =>
null; -- NOP, undocumented
when "01111110"|"01111111" =>
-- NOP, undocumented
null;
-- 8 BIT LOAD GROUP
when "01010111" =>
-- LD A,I
Special_LD <= "100";
TStates <= "101";
when "01011111" =>
-- LD A,R
Special_LD <= "101";
TStates <= "101";
when "01000111" =>
-- LD I,A
Special_LD <= "110";
TStates <= "101";
when "01001111" =>
-- LD R,A
Special_LD <= "111";
TStates <= "101";
-- 16 BIT LOAD GROUP
when "01001011"|"01011011"|"01101011"|"01111011" =>
-- LD dd,(nn)
MCycles <= "101";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
LDZ <= '1';
when 3 =>
Set_Addr_To <= aZI;
Inc_PC <= '1';
LDW <= '1';
when 4 =>
Read_To_Reg <= '1';
if IR(5 downto 4) = "11" then
Set_BusA_To <= "1000";
else
Set_BusA_To(2 downto 1) <= IR(5 downto 4);
Set_BusA_To(0) <= '1';
end if;
Inc_WZ <= '1';
Set_Addr_To <= aZI;
when 5 =>
Read_To_Reg <= '1';
if IR(5 downto 4) = "11" then
Set_BusA_To <= "1001";
else
Set_BusA_To(2 downto 1) <= IR(5 downto 4);
Set_BusA_To(0) <= '0';
end if;
when others => null;
end case;
when "01000011"|"01010011"|"01100011"|"01110011" =>
-- LD (nn),dd
MCycles <= "101";
case to_integer(unsigned(MCycle)) is
when 2 =>
Inc_PC <= '1';
LDZ <= '1';
when 3 =>
Set_Addr_To <= aZI;
Inc_PC <= '1';
LDW <= '1';
if IR(5 downto 4) = "11" then
Set_BusB_To <= "1000";
else
Set_BusB_To(2 downto 1) <= IR(5 downto 4);
Set_BusB_To(0) <= '1';
Set_BusB_To(3) <= '0';
end if;
when 4 =>
Inc_WZ <= '1';
Set_Addr_To <= aZI;
Write <= '1';
if IR(5 downto 4) = "11" then
Set_BusB_To <= "1001";
else
Set_BusB_To(2 downto 1) <= IR(5 downto 4);
Set_BusB_To(0) <= '0';
Set_BusB_To(3) <= '0';
end if;
when 5 =>
Write <= '1';
when others => null;
end case;
when "10100000" | "10101000" | "10110000" | "10111000" =>
-- LDI, LDD, LDIR, LDDR
MCycles <= "100";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aXY;
IncDec_16 <= "1100"; -- BC
when 2 =>
Set_BusB_To <= "0110";
Set_BusA_To(2 downto 0) <= "111";
ALU_Op <= "0000";
Set_Addr_To <= aDE;
if IR(3) = '0' then
IncDec_16 <= "0110"; -- IX
else
IncDec_16 <= "1110";
end if;
when 3 =>
I_BT <= '1';
TStates <= "101";
Write <= '1';
if IR(3) = '0' then
IncDec_16 <= "0101"; -- DE
else
IncDec_16 <= "1101";
end if;
when 4 =>
NoRead <= '1';
TStates <= "101";
when others => null;
end case;
when "10100001" | "10101001" | "10110001" | "10111001" =>
-- CPI, CPD, CPIR, CPDR
MCycles <= "100";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aXY;
IncDec_16 <= "1100"; -- BC
when 2 =>
Set_BusB_To <= "0110";
Set_BusA_To(2 downto 0) <= "111";
ALU_Op <= "0111";
Save_ALU <= '1';
PreserveC <= '1';
if IR(3) = '0' then
IncDec_16 <= "0110";
else
IncDec_16 <= "1110";
end if;
when 3 =>
NoRead <= '1';
I_BC <= '1';
TStates <= "101";
when 4 =>
NoRead <= '1';
TStates <= "101";
when others => null;
end case;
when "01000100"|"01001100"|"01010100"|"01011100"|"01100100"|"01101100"|"01110100"|"01111100" =>
-- NEG
Alu_OP <= "0010";
Set_BusB_To <= "0111";
Set_BusA_To <= "1010";
Read_To_Acc <= '1';
Save_ALU <= '1';
when "01000110"|"01001110"|"01100110"|"01101110" =>
-- IM 0
IMode <= "00";
when "01010110"|"01110110" =>
-- IM 1
IMode <= "01";
when "01011110"|"01110111" =>
-- IM 2
IMode <= "10";
-- 16 bit arithmetic
when "01001010"|"01011010"|"01101010"|"01111010" =>
-- ADC HL,ss
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 2 =>
NoRead <= '1';
ALU_Op <= "0001";
Read_To_Reg <= '1';
Save_ALU <= '1';
Set_BusA_To(2 downto 0) <= "101";
case to_integer(unsigned(IR(5 downto 4))) is
when 0|1|2 =>
Set_BusB_To(2 downto 1) <= IR(5 downto 4);
Set_BusB_To(0) <= '1';
when others =>
Set_BusB_To <= "1000";
end case;
TStates <= "100";
when 3 =>
NoRead <= '1';
Read_To_Reg <= '1';
Save_ALU <= '1';
ALU_Op <= "0001";
Set_BusA_To(2 downto 0) <= "100";
case to_integer(unsigned(IR(5 downto 4))) is
when 0|1|2 =>
Set_BusB_To(2 downto 1) <= IR(5 downto 4);
Set_BusB_To(0) <= '0';
when others =>
Set_BusB_To <= "1001";
end case;
when others =>
end case;
when "01000010"|"01010010"|"01100010"|"01110010" =>
-- SBC HL,ss
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 2 =>
NoRead <= '1';
ALU_Op <= "0011";
Read_To_Reg <= '1';
Save_ALU <= '1';
Set_BusA_To(2 downto 0) <= "101";
case to_integer(unsigned(IR(5 downto 4))) is
when 0|1|2 =>
Set_BusB_To(2 downto 1) <= IR(5 downto 4);
Set_BusB_To(0) <= '1';
when others =>
Set_BusB_To <= "1000";
end case;
TStates <= "100";
when 3 =>
NoRead <= '1';
ALU_Op <= "0011";
Read_To_Reg <= '1';
Save_ALU <= '1';
Set_BusA_To(2 downto 0) <= "100";
case to_integer(unsigned(IR(5 downto 4))) is
when 0|1|2 =>
Set_BusB_To(2 downto 1) <= IR(5 downto 4);
when others =>
Set_BusB_To <= "1001";
end case;
when others =>
end case;
when "01101111" =>
-- RLD
MCycles <= "100";
case to_integer(unsigned(MCycle)) is
when 2 =>
NoRead <= '1';
Set_Addr_To <= aXY;
when 3 =>
Read_To_Reg <= '1';
Set_BusB_To(2 downto 0) <= "110";
Set_BusA_To(2 downto 0) <= "111";
ALU_Op <= "1101";
TStates <= "100";
Set_Addr_To <= aXY;
Save_ALU <= '1';
when 4 =>
I_RLD <= '1';
Write <= '1';
when others =>
end case;
when "01100111" =>
-- RRD
MCycles <= "100";
case to_integer(unsigned(MCycle)) is
when 2 =>
Set_Addr_To <= aXY;
when 3 =>
Read_To_Reg <= '1';
Set_BusB_To(2 downto 0) <= "110";
Set_BusA_To(2 downto 0) <= "111";
ALU_Op <= "1110";
TStates <= "100";
Set_Addr_To <= aXY;
Save_ALU <= '1';
when 4 =>
I_RRD <= '1';
Write <= '1';
when others =>
end case;
when "01000101"|"01001101"|"01010101"|"01011101"|"01100101"|"01101101"|"01110101"|"01111101" =>
-- RETI, RETN
MCycles <= "011";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_TO <= aSP;
when 2 =>
IncDec_16 <= "0111";
Set_Addr_To <= aSP;
LDZ <= '1';
when 3 =>
Jump <= '1';
IncDec_16 <= "0111";
I_RETN <= '1';
when others => null;
end case;
when "01000000"|"01001000"|"01010000"|"01011000"|"01100000"|"01101000"|"01110000"|"01111000" =>
-- IN r,(C)
MCycles <= "010";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aBC;
when 2 =>
IORQ <= '1';
if IR(5 downto 3) /= "110" then
Read_To_Reg <= '1';
Set_BusA_To(2 downto 0) <= IR(5 downto 3);
end if;
I_INRC <= '1';
when others =>
end case;
when "01000001"|"01001001"|"01010001"|"01011001"|"01100001"|"01101001"|"01110001"|"01111001" =>
-- OUT (C),r
-- OUT (C),0
MCycles <= "010";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aBC;
Set_BusB_To(2 downto 0) <= IR(5 downto 3);
if IR(5 downto 3) = "110" then
Set_BusB_To(3) <= '1';
end if;
when 2 =>
Write <= '1';
IORQ <= '1';
when others =>
end case;
when "10100010" | "10101010" | "10110010" | "10111010" =>
-- INI, IND, INIR, INDR
-- note B is decremented AFTER being put on the bus
MCycles <= "100";
case to_integer(unsigned(MCycle)) is
when 1 =>
Set_Addr_To <= aBC;
Set_BusB_To <= "1010";
Set_BusA_To <= "0000";
Read_To_Reg <= '1';
Save_ALU <= '1';
ALU_Op <= "0010";
when 2 =>
IORQ <= '1';
Set_BusB_To <= "0110";
Set_Addr_To <= aXY;
when 3 =>
if IR(3) = '0' then
--IncDec_16 <= "0010";
IncDec_16 <= "0110";
else
--IncDec_16 <= "1010";
IncDec_16 <= "1110";
end if;
TStates <= "100";
Write <= '1';
I_BTR <= '1';
when 4 =>
NoRead <= '1';
TStates <= "101";
when others => null;
end case;
when "10100011" | "10101011" | "10110011" | "10111011" =>
-- OUTI, OUTD, OTIR, OTDR
-- note B is decremented BEFORE being put on the bus.
-- mikej fix for hl inc
MCycles <= "100";
case to_integer(unsigned(MCycle)) is
when 1 =>
TStates <= "101";
Set_Addr_To <= aXY;
Set_BusB_To <= "1010";
Set_BusA_To <= "0000";
Read_To_Reg <= '1';
Save_ALU <= '1';
ALU_Op <= "0010";
when 2 =>
Set_BusB_To <= "0110";
Set_Addr_To <= aBC;
when 3 =>
if IR(3) = '0' then
IncDec_16 <= "0110"; -- mikej
else
IncDec_16 <= "1110"; -- mikej
end if;
IORQ <= '1';
Write <= '1';
I_BTR <= '1';
when 4 =>
NoRead <= '1';
TStates <= "101";
when others => null;
end case;
end case;
end case;
if Mode = 1 then
if MCycle = "001" then
-- TStates <= "100";
else
TStates <= "011";
end if;
end if;
if Mode = 3 then
if MCycle = "001" then
-- TStates <= "100";
else
TStates <= "100";
end if;
end if;
if Mode < 2 then
if MCycle = "110" then
Inc_PC <= '1';
if Mode = 1 then
Set_Addr_To <= aXY;
TStates <= "100";
Set_BusB_To(2 downto 0) <= SSS;
Set_BusB_To(3) <= '0';
end if;
if IRB = "00110110" or IRB = "11001011" then
Set_Addr_To <= aNone;
end if;
end if;
if MCycle = "111" then
if Mode = 0 then
TStates <= "101";
end if;
if ISet /= "01" then
Set_Addr_To <= aXY;
end if;
Set_BusB_To(2 downto 0) <= SSS;
Set_BusB_To(3) <= '0';
if IRB = "00110110" or ISet = "01" then
-- LD (HL),n
Inc_PC <= '1';
else
NoRead <= '1';
end if;
end if;
end if;
end process;
end;