---------------------------------------------------------------------------------                                                                           ----          X       X   XXXXXX    XXXXXX    XXXXXX    XXXXXX      X          ----          XX     XX  X      X  X      X  X      X  X           XX          ----          X X   X X  X         X      X  X      X  X          X X          ----          X  X X  X  X         X      X  X      X  X         X  X          ----          X   X   X  X          XXXXXX   X      X   XXXXXX      X          ----          X       X  X         X      X  X      X         X     X          ----          X       X  X         X      X  X      X         X     X          ----          X       X  X      X  X      X  X      X         X     X          ----          X       X   XXXXXX    XXXXXX    XXXXXX    XXXXXX      X          ----                                                                           ----                                                                           ----                       O R E G A N O   S Y S T E M S                       ----                                                                           ----                            Design & Consulting                            ----                                                                           -----------------------------------------------------------------------------------                                                                           ----         Web:           http://www.oregano.at/                             ----                                                                           ----         Contact:       mc8051@oregano.at                                  ----                                                                           -----------------------------------------------------------------------------------                                                                           ----  MC8051 - VHDL 8051 Microcontroller IP Core                               ----  Copyright (C) 2001 OREGANO SYSTEMS                                       ----                                                                           ----  This library is free software; you can redistribute it and/or            ----  modify it under the terms of the GNU Lesser General Public               ----  License as published by the Free Software Foundation; either             ----  version 2.1 of the License, or (at your option) any later version.       ----                                                                           ----  This library is distributed in the hope that it will be useful,          ----  but WITHOUT ANY WARRANTY; without even the implied warranty of           ----  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU        ----  Lesser General Public License for more details.                          ----                                                                           ----  Full details of the license can be found in the file LGPL.TXT.           ----                                                                           ----  You should have received a copy of the GNU Lesser General Public         ----  License along with this library; if not, write to the Free Software      ----  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA  ----                                                                           ---------------------------------------------------------------------------------------         Author:                 Helmut Mayrhofer----         Filename:               control_fsm_rtl.vhd----         Date of Creation:       Mon Aug  9 12:14:48 1999----         Version:                $Revision: 1.6 $----         Date of Latest Version: $Date: 2002/01/07 12:17:44 $------         Description: Decode instruction and execute it. Pure combinational--                      descripton of the finite state machine.---------------------------------------------------------------------------------------architecture rtl of control_fsm is  alias CY : std_logic is psw(7);              -- carry  alias AC : std_logic is psw(6);              -- auxilary carry  alias OV : std_logic is psw(2);              -- overflow flag  alias EA:  std_logic is ie(7);               -- enable interupts  alias ES:  std_logic is ie(4);               -- enable serial interupt  alias ET1: std_logic is ie(3);               -- enable timer 1 interupt  alias EX1: std_logic is ie(2);               -- enable external 1 interupt  alias ET0: std_logic is ie(1);               -- enable timer 0 interupt  alias EX0: std_logic is ie(0);               -- enable external 0 interupt  alias PS0: std_logic is ip(4);               -- priority of serial interupt  alias PT1: std_logic is ip(3);               -- priority of timer1 interupt  alias PX1: std_logic is ip(2);               -- priority of ext1 interupt  alias PT0: std_logic is ip(1);               -- priority of timer0 interupt  alias PX0: std_logic is ip(0);               -- priority of ext0 interupt  signal state:         t_state;               -- actual state  signal s_nextstate:   t_state;               -- enable signal for state  signal s_instr_category : t_instr_category;  -- predecoded insturction    signal s_help:        unsigned (7 downto 0); -- general help-register  signal s_bit_data :   std_logic;             -- bitdata from MUX  signal s_intpre:      std_logic;             -- an interrupt must start  signal s_intpre2:     std_logic;             -- prepare for interrupt  signal s_inthigh:     std_logic;             -- high priority int is running  signal s_intlow:      std_logic;             -- low priority int is running  signal s_tf1 :        std_logic;               -- Timer1-Overflowflag  signal s_tf0 :        std_logic;               -- Timer0-Overflowflag  signal s_ie1 :        std_logic;               -- ExtINT1-Flag  signal s_it1 :        std_logic;               -- edge-sensitive-Bit EXT1  signal s_ie0 :        std_logic;               -- ExtINT0-Flag  signal s_it0 :        std_logic;               -- edge-sensitive-Bit EXT0  signal s_ri : std_logic;                       -- serial receive-ready  signal s_ti : std_logic;                       -- serial transmit-ready  signal s_command:     std_logic_vector (7 downto 0); -- actual command  signal s_pc_inc_en  : std_logic_vector (3 downto 0);  -- pc control  signal s_regs_wr_en : std_logic_vector (2 downto 0);  -- write control  signal s_data_mux   : std_logic_vector (3 downto 0);  -- data control  signal s_bdata_mux  : std_logic_vector (3 downto 0);  -- bitdata control  signal s_adr_mux    : std_logic_vector (3 downto 0);  -- adress control  signal s_adrx_mux   : std_logic_vector (1 downto 0);  -- ext. adress control  signal s_wrx_mux    : std_logic;                      -- ext. write control  signal s_help_en    : std_logic_vector (3 downto 0);  -- helpreg control  signal s_help16_en  : std_logic_vector (1 downto 0);  -- help16 control  signal s_helpb_en   : std_logic;                      -- helpbit control  signal s_intpre2_d  : std_logic;                      -- intput of intpre2  signal s_intpre2_en : std_logic;                      -- control  signal s_intlow_d   : std_logic;                      -- input of intlow  signal s_intlow_en  : std_logic;                      -- control  signal s_inthigh_d  : std_logic;                      -- input of inthigh  signal s_inthigh_en : std_logic;                      -- controlbegin  -- some simple signal-assignments for outputs  pc_inc_en_o  <= s_pc_inc_en;  nextstate_o  <= s_nextstate;  adr_mux_o    <= s_adr_mux;  adrx_mux_o   <= s_adrx_mux;  wrx_mux_o    <= s_wrx_mux;  data_mux_o   <= s_data_mux;  bdata_mux_o  <= s_bdata_mux;  regs_wr_en_o <= s_regs_wr_en;  help_en_o    <= s_help_en;  help16_en_o  <= s_help16_en;  helpb_en_o   <= s_helpb_en;  inthigh_en_o <= s_inthigh_en;  intlow_en_o  <= s_intlow_en;  intpre2_en_o <= s_intpre2_en;  inthigh_d_o  <= s_inthigh_d;  intlow_d_o   <= s_intlow_d;  intpre2_d_o  <= s_intpre2_d;  -- some simple signal assignments from intputs  state      <= state_i;  s_help     <= unsigned(help_i);  s_bit_data <= bit_data_i;  s_command  <= command_i;  s_inthigh  <= inthigh_i;  s_intlow   <= intlow_i;  s_intpre   <= intpre_i;  s_intpre2  <= intpre2_i;  s_ti       <= ti_i;  s_ri       <= ri_i;  s_it0      <= it0_i;  s_ie0      <= ie0_i;  s_it1      <= it1_i;  s_ie1      <= ie1_i;  s_tf0      <= tf0_i;  s_tf1      <= tf1_i;  -- predecode instruction  s_instr_category <=    IC_ACALL          when s_command(4 downto 0) = ACALL          else    IC_ADD_A_RR       when s_command(7 downto 3) = ADD_A_RR       else    IC_ADD_A_D        when s_command             = ADD_A_D        else    IC_ADD_A_ATRI     when s_command(7 downto 1) = ADD_A_ATRI     else    IC_ADD_A_DATA     when s_command             = ADD_A_DATA     else    IC_ADDC_A_RR      when s_command(7 downto 3) = ADDC_A_RR      else    IC_ADDC_A_D       when s_command             = ADDC_A_D       else    IC_ADDC_A_ATRI    when s_command(7 downto 1) = ADDC_A_ATRI    else    IC_ADDC_A_DATA    when s_command             = ADDC_A_DATA    else    IC_AJMP           when s_command(4 downto 0) = AJMP           else    IC_ANL_A_RR       when s_command(7 downto 3) = ANL_A_RR       else    IC_ANL_A_D        when s_command             = ANL_A_D        else    IC_ANL_A_ATRI     when s_command(7 downto 1) = ANL_A_ATRI     else    IC_ANL_A_DATA     when s_command             = ANL_A_DATA     else    IC_ANL_D_A        when s_command             = ANL_D_A        else    IC_ANL_D_DATA     when s_command             = ANL_D_DATA     else    IC_ANL_C_BIT      when s_command             = ANL_C_BIT      else    IC_ANL_C_NBIT     when s_command             = ANL_C_NBIT     else    IC_CJNE_A_D       when s_command             = CJNE_A_D       else    IC_CJNE_A_DATA    when s_command             = CJNE_A_DATA    else    IC_CJNE_RR_DATA   when s_command(7 downto 3) = CJNE_RR_DATA   else    IC_CJNE_ATRI_DATA when s_command(7 downto 1) = CJNE_ATRI_DATA else    IC_CLR_A          when s_command             = CLR_A          else    IC_CLR_C          when s_command             = CLR_C          else    IC_CLR_BIT        when s_command             = CLR_BIT        else    IC_CPL_A          when s_command             = CPL_A          else    IC_CPL_C          when s_command             = CPL_C          else    IC_CPL_BIT        when s_command             = CPL_BIT        else    IC_DA_A           when s_command             = DA_A           else    IC_DEC_A          when s_command             = DEC_A          else    IC_DEC_RR         when s_command(7 downto 3) = DEC_RR         else    IC_DEC_D          when s_command             = DEC_D          else    IC_DEC_ATRI       when s_command(7 downto 1) = DEC_ATRI       else    IC_DIV_AB         when s_command             = DIV_AB         else    IC_DJNZ_RR        when s_command(7 downto 3) = DJNZ_RR        else    IC_DJNZ_D         when s_command             = DJNZ_D         else    IC_INC_A          when s_command             = INC_A          else    IC_INC_RR         when s_command(7 downto 3) = INC_RR         else    IC_INC_D          when s_command             = INC_D          else    IC_INC_ATRI       when s_command(7 downto 1) = INC_ATRI       else    IC_INC_DPTR       when s_command             = INC_DPTR       else    IC_JB             when s_command             = JB             else    IC_JBC            when s_command             = JBC            else    IC_JC             when s_command             = JC             else    IC_JMP_A_DPTR     when s_command             = JMP_A_DPTR     else    IC_JNB            when s_command             = JNB            else    IC_JNC            when s_command             = JNC            else    IC_JNZ            when s_command             = JNZ            else    IC_JZ             when s_command             = JZ             else    IC_LCALL          when s_command             = LCALL          else    IC_LJMP           when s_command             = LJMP           else    IC_MOV_A_RR       when s_command(7 downto 3) = MOV_A_RR       else    IC_MOV_A_D        when s_command             = MOV_A_D        else    IC_MOV_A_ATRI     when s_command(7 downto 1) = MOV_A_ATRI     else    IC_MOV_A_DATA     when s_command             = MOV_A_DATA     else    IC_MOV_RR_A       when s_command(7 downto 3) = MOV_RR_A       else    IC_MOV_RR_D       when s_command(7 downto 3) = MOV_RR_D       else    IC_MOV_RR_DATA    when s_command(7 downto 3) = MOV_RR_DATA    else    IC_MOV_D_A        when s_command             = MOV_D_A        else    IC_MOV_D_RR       when s_command(7 downto 3) = MOV_D_RR       else    IC_MOV_D_D        when s_command             = MOV_D_D        else    IC_MOV_D_ATRI     when s_command(7 downto 1) = MOV_D_ATRI     else    IC_MOV_D_DATA     when s_command             = MOV_D_DATA     else    IC_MOV_ATRI_A     when s_command(7 downto 1) = MOV_ATRI_A     else    IC_MOV_ATRI_D     when s_command(7 downto 1) = MOV_ATRI_D     else    IC_MOV_ATRI_DATA  when s_command(7 downto 1) = MOV_ATRI_DATA  else    IC_MOVC_A_ATDPTR  when s_command             = MOVC_A_ATDPTR  else    IC_MOVC_A_ATPC    when s_command             = MOVC_A_ATPC    else    IC_MOVX_A_ATRI    when s_command(7 downto 1) = MOVX_A_ATRI    else    IC_MOVX_A_ATDPTR  when s_command             = MOVX_A_ATDPTR  else    IC_MOVX_ATRI_A    when s_command(7 downto 1) = MOVX_ATRI_A    else    IC_MOVX_ATDPTR_A  when s_command             = MOVX_ATDPTR_A  else    IC_MOV_C_BIT      when s_command             = MOV_C_BIT      else    IC_MOV_BIT_C      when s_command             = MOV_BIT_C      else    IC_MOV_DPTR_DATA  when s_command             = MOV_DPTR_DATA  else    IC_MUL_AB         when s_command             = MUL_AB         else    IC_NOP            when s_command             = NOP            else    IC_ORL_A_RR       when s_command(7 downto 3) = ORL_A_RR       else    IC_ORL_A_D        when s_command             = ORL_A_D        else    IC_ORL_A_ATRI     when s_command(7 downto 1) = ORL_A_ATRI     else    IC_ORL_A_DATA     when s_command             = ORL_A_DATA     else    IC_ORL_D_A        when s_command             = ORL_D_A        else    IC_ORL_D_DATA     when s_command             = ORL_D_DATA     else    IC_ORL_C_BIT      when s_command             = ORL_C_BIT      else    IC_ORL_C_NBIT     when s_command             = ORL_C_NBIT     else    IC_POP            when s_command             = POP            else    IC_PUSH           when s_command             = PUSH           else    IC_RET            when s_command             = RET            else    IC_RETI           when s_command             = RETI           else    IC_RL_A           when s_command             = RL_A           else    IC_RLC_A          when s_command             = RLC_A          else    IC_RR_A           when s_command             = RR_A           else    IC_RRC_A          when s_command             = RRC_A          else    IC_SETB_C         when s_command             = SETB_C         else    IC_SETB_BIT       when s_command             = SETB_BIT       else    IC_SJMP           when s_command             = SJMP           else    IC_SUBB_A_RR      when s_command(7 downto 3) = SUBB_A_RR      else    IC_SUBB_A_D       when s_command             = SUBB_A_D       else    IC_SUBB_A_ATRI    when s_command(7 downto 1) = SUBB_A_ATRI    else    IC_SUBB_A_DATA    when s_command             = SUBB_A_DATA    else    IC_SWAP_A         when s_command             = SWAP_A         else    IC_XCH_A_RR       when s_command(7 downto 3) = XCH_A_RR       else    IC_XCH_A_D        when s_command             = XCH_A_D        else    IC_XCH_A_ATRI     when s_command(7 downto 1) = XCH_A_ATRI     else    IC_XCHD_A_ATRI    when s_command(7 downto 1) = XCHD_A_ATRI    else    IC_XRL_A_RR       when s_command(7 downto 3) = XRL_A_RR       else    IC_XRL_A_D        when s_command             = XRL_A_D        else    IC_XRL_A_ATRI     when s_command(7 downto 1) = XRL_A_ATRI     else    IC_XRL_A_DATA     when s_command             = XRL_A_DATA     else    IC_XRL_D_A        when s_command             = XRL_D_A        else