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// // TV80 8-Bit Microprocessor Core // Based on the VHDL T80 core by Daniel Wallner (jesus@opencores.org) // // Copyright (c) 2004 Guy Hutchison (ghutchis@opencores.org) // // Permission is hereby granted, free of charge, to any person obtaining a // copy of this software and associated documentation files (the "Software"), // to deal in the Software without restriction, including without limitation // the rights to use, copy, modify, merge, publish, distribute, sublicense, // and/or sell copies of the Software, and to permit persons to whom the // Software is furnished to do so, subject to the following conditions: // // The above copyright notice and this permission notice shall be included // in all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. // IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY // CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, // TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE // SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. module tv80_core (/*AUTOARG*/ // Outputs m1_n, iorq, no_read, write, rfsh_n, halt_n, busak_n, A, do, mc, ts, intcycle_n, IntE, stop, // Inputs reset_n, clk, cen, wait_n, int_n, nmi_n, busrq_n, dinst, di ); // Beginning of automatic inputs (from unused autoinst inputs) // End of automatics parameter Mode = 1; // 0 => Z80, 1 => Fast Z80, 2 => 8080, 3 => GB parameter IOWait = 1; // 1 => Single cycle I/O, 1 => Std I/O cycle parameter Flag_C = 0; parameter Flag_N = 1; parameter Flag_P = 2; parameter Flag_X = 3; parameter Flag_H = 4; parameter Flag_Y = 5; parameter Flag_Z = 6; parameter Flag_S = 7; input reset_n; input clk; input cen; input wait_n; input int_n; input nmi_n; input busrq_n; output m1_n; output iorq; output no_read; output write; output rfsh_n; output halt_n; output busak_n; output [15:0] A; input [7:0] dinst; input [7:0] di; output [7:0] do; output [2:0] mc; output [2:0] ts; output intcycle_n; output IntE; output stop; reg m1_n; reg iorq; reg rfsh_n; reg halt_n; reg busak_n; reg [15:0] A; reg [7:0] do; reg [2:0] mc; reg [2:0] ts; reg intcycle_n; reg IntE; reg stop; parameter aNone = 3'b111; parameter aBC = 3'b000; parameter aDE = 3'b001; parameter aXY = 3'b010; parameter aIOA = 3'b100; parameter aSP = 3'b101; parameter aZI = 3'b110; // Registers reg [7:0] ACC, F; reg [7:0] Ap, Fp; reg [7:0] I; reg [7:0] R; reg [15:0] SP, PC; reg [7:0] RegDIH; reg [7:0] RegDIL; wire [15:0] RegBusA; wire [15:0] RegBusB; wire [15:0] RegBusC; reg [2:0] RegAddrA_r; reg [2:0] RegAddrA; reg [2:0] RegAddrB_r; reg [2:0] RegAddrB; reg [2:0] RegAddrC; reg RegWEH; reg RegWEL; reg Alternate; // Help Registers reg [15:0] TmpAddr; // Temporary address register reg [7:0] IR; // Instruction register reg [1:0] ISet; // Instruction set selector reg [15:0] RegBusA_r; reg [15:0] ID16; reg [7:0] Save_Mux; reg [2:0] tstate; reg [2:0] mcycle; reg IntE_FF1; reg IntE_FF2; reg Halt_FF; reg BusReq_s; reg BusAck; reg ClkEn; reg NMI_s; reg INT_s; reg [1:0] IStatus; reg [7:0] DI_Reg; reg T_Res; reg [1:0] XY_State; reg [2:0] Pre_XY_F_M; reg NextIs_XY_Fetch; reg XY_Ind; reg No_BTR; reg BTR_r; reg Auto_Wait; reg Auto_Wait_t1; reg Auto_Wait_t2; reg IncDecZ; // ALU signals reg [7:0] BusB; reg [7:0] BusA; wire [7:0] ALU_Q; wire [7:0] F_Out; // Registered micro code outputs reg [4:0] Read_To_Reg_r; reg Arith16_r; reg Z16_r; reg [3:0] ALU_Op_r; reg Save_ALU_r; reg PreserveC_r; reg [2:0] mcycles; // Micro code outputs wire [2:0] mcycles_d; wire [2:0] tstates; reg IntCycle; reg NMICycle; wire Inc_PC; wire Inc_WZ; wire [3:0] IncDec_16; wire [1:0] Prefix; wire Read_To_Acc; wire Read_To_Reg; wire [3:0] Set_BusB_To; wire [3:0] Set_BusA_To; wire [3:0] ALU_Op; wire Save_ALU; wire PreserveC; wire Arith16; wire [2:0] Set_Addr_To; wire Jump; wire JumpE; wire JumpXY; wire Call; wire RstP; wire LDZ; wire LDW; wire LDSPHL; wire iorq_i; wire [2:0] Special_LD; wire ExchangeDH; wire ExchangeRp; wire ExchangeAF; wire ExchangeRS; wire I_DJNZ; wire I_CPL; wire I_CCF; wire I_SCF; wire I_RETN; wire I_BT; wire I_BC; wire I_BTR; wire I_RLD; wire I_RRD; wire I_INRC; wire SetDI; wire SetEI; wire [1:0] IMode; wire Halt; reg [15:0] PC16; reg [15:0] PC16_B; reg [15:0] SP16, SP16_A, SP16_B; reg [15:0] ID16_B; reg Oldnmi_n; tv80_mcode #(Mode, Flag_C, Flag_N, Flag_P, Flag_X, Flag_H, Flag_Y, Flag_Z, Flag_S) i_mcode ( .IR (IR), .ISet (ISet), .MCycle (mcycle), .F (F), .NMICycle (NMICycle), .IntCycle (IntCycle), .MCycles (mcycles_d), .TStates (tstates), .Prefix (Prefix), .Inc_PC (Inc_PC), .Inc_WZ (Inc_WZ), .IncDec_16 (IncDec_16), .Read_To_Acc (Read_To_Acc), .Read_To_Reg (Read_To_Reg), .Set_BusB_To (Set_BusB_To), .Set_BusA_To (Set_BusA_To), .ALU_Op (ALU_Op), .Save_ALU (Save_ALU), .PreserveC (PreserveC), .Arith16 (Arith16), .Set_Addr_To (Set_Addr_To), .IORQ (iorq_i), .Jump (Jump), .JumpE (JumpE), .JumpXY (JumpXY), .Call (Call), .RstP (RstP), .LDZ (LDZ), .LDW (LDW), .LDSPHL (LDSPHL), .Special_LD (Special_LD), .ExchangeDH (ExchangeDH), .ExchangeRp (ExchangeRp), .ExchangeAF (ExchangeAF), .ExchangeRS (ExchangeRS), .I_DJNZ (I_DJNZ), .I_CPL (I_CPL), .I_CCF (I_CCF), .I_SCF (I_SCF), .I_RETN (I_RETN), .I_BT (I_BT), .I_BC (I_BC), .I_BTR (I_BTR), .I_RLD (I_RLD), .I_RRD (I_RRD), .I_INRC (I_INRC), .SetDI (SetDI), .SetEI (SetEI), .IMode (IMode), .Halt (Halt), .NoRead (no_read), .Write (write) ); tv80_alu #(Mode, Flag_C, Flag_N, Flag_P, Flag_X, Flag_H, Flag_Y, Flag_Z, Flag_S) i_alu ( .Arith16 (Arith16_r), .Z16 (Z16_r), .ALU_Op (ALU_Op_r), .IR (IR[5:0]), .ISet (ISet), .BusA (BusA), .BusB (BusB), .F_In (F), .Q (ALU_Q), .F_Out (F_Out) ); always @(/*AUTOSENSE*/ALU_Q or BusAck or BusB or DI_Reg or ExchangeRp or IR or Save_ALU_r or Set_Addr_To or XY_Ind or XY_State or cen or mcycle or tstate or tstates) begin ClkEn = cen && ~ BusAck; if (tstate == tstates) T_Res = 1'b1; else T_Res = 1'b0; if (XY_State != 2'b00 && XY_Ind == 1'b0 && ((Set_Addr_To == aXY) || (mcycle == 3'b001 && IR == 8'b11001011) || (mcycle == 3'b001 && IR == 8'b00110110))) NextIs_XY_Fetch = 1'b1; else NextIs_XY_Fetch = 1'b0; if (ExchangeRp) Save_Mux = BusB; else if (!Save_ALU_r) Save_Mux = DI_Reg; else Save_Mux = ALU_Q; end // always @ * always @ (posedge clk) begin if (reset_n == 1'b0 ) begin PC <= #1 0; // Program Counter A <= #1 0; TmpAddr <= #1 0; IR <= #1 8'b00000000; ISet <= #1 2'b00; XY_State <= #1 2'b00; IStatus <= #1 2'b00; mcycles <= #1 3'b000; do <= #1 8'b00000000; ACC <= #1 8'hFF; F <= #1 8'hFF; Ap <= #1 8'hFF; Fp <= #1 8'hFF; I <= #1 0; R <= #1 0; SP <= #1 16'hFFFF; Alternate <= #1 1'b0; Read_To_Reg_r <= #1 5'b00000; Arith16_r <= #1 1'b0; BTR_r <= #1 1'b0; Z16_r <= #1 1'b0; ALU_Op_r <= #1 4'b0000; Save_ALU_r <= #1 1'b0; PreserveC_r <= #1 1'b0; XY_Ind <= #1 1'b0; end else begin if (ClkEn == 1'b1 ) begin ALU_Op_r <= #1 4'b0000; Save_ALU_r <= #1 1'b0; Read_To_Reg_r <= #1 5'b00000; mcycles <= #1 mcycles_d; if (IMode != 2'b11 ) begin IStatus <= #1 IMode; end Arith16_r <= #1 Arith16; PreserveC_r <= #1 PreserveC; if (ISet == 2'b10 && ALU_Op[2] == 1'b0 && ALU_Op[0] == 1'b1 && mcycle == 3'b011 ) begin Z16_r <= #1 1'b1; end else begin Z16_r <= #1 1'b0; end if (mcycle == 3'b001 && tstate[2] == 1'b0 ) begin // mcycle == 1 && tstate == 1, 2, || 3 if (tstate == 2 && wait_n == 1'b1 ) begin if (Mode < 2 ) begin A[7:0] <= #1 R; A[15:8] <= #1 I; R[6:0] <= #1 R[6:0] + 1; end if (Jump == 1'b0 && Call == 1'b0 && NMICycle == 1'b0 && IntCycle == 1'b0 && ~ (Halt_FF == 1'b1 || Halt == 1'b1) ) begin PC <= #1 PC16; end if (IntCycle == 1'b1 && IStatus == 2'b01 ) begin IR <= #1 8'b11111111; end else if (Halt_FF == 1'b1 || (IntCycle == 1'b1 && IStatus == 2'b10) || NMICycle == 1'b1 ) begin IR <= #1 8'b00000000; end else begin IR <= #1 dinst; end ISet <= #1 2'b00; if (Prefix != 2'b00 ) begin if (Prefix == 2'b11 ) begin if (IR[5] == 1'b1 ) begin XY_State <= #1 2'b10; end else begin XY_State <= #1 2'b01; end end else begin if (Prefix == 2'b10 ) begin XY_State <= #1 2'b00; XY_Ind <= #1 1'b0; end ISet <= #1 Prefix; end end else begin XY_State <= #1 2'b00; XY_Ind <= #1 1'b0; end end // if (tstate == 2 && wait_n == 1'b1 ) end else begin // either (mcycle > 1) OR (mcycle == 1 AND tstate > 3) if (mcycle == 3'b110 ) begin XY_Ind <= #1 1'b1; if (Prefix == 2'b01 ) begin ISet <= #1 2'b01; end end if (T_Res == 1'b1 ) begin BTR_r <= #1 (I_BT || I_BC || I_BTR) && ~ No_BTR; if (Jump == 1'b1 ) begin A[15:8] <= #1 DI_Reg; A[7:0] <= #1 TmpAddr[7:0]; PC[15:8] <= #1 DI_Reg; PC[7:0] <= #1 TmpAddr[7:0]; end else if (JumpXY == 1'b1 ) begin A <= #1 RegBusC; PC <= #1 RegBusC; end else if (Call == 1'b1 || RstP == 1'b1 ) begin A <= #1 TmpAddr; PC <= #1 TmpAddr; end else if (mcycle == mcycles && NMICycle == 1'b1 ) begin A <= #1 16'b0000000001100110; PC <= #1 16'b0000000001100110; end else if (mcycle == 3'b011 && IntCycle == 1'b1 && IStatus == 2'b10 ) begin A[15:8] <= #1 I; A[7:0] <= #1 TmpAddr[7:0]; PC[15:8] <= #1 I; PC[7:0] <= #1 TmpAddr[7:0]; end else begin case (Set_Addr_To) aXY : begin if (XY_State == 2'b00 ) begin A <= #1 RegBusC; end else begin if (NextIs_XY_Fetch == 1'b1 ) begin A <= #1 PC; end else begin A <= #1 TmpAddr; end end // else: !if(XY_State == 2'b00 ) end // case: aXY aIOA : begin if (Mode == 3 ) begin // Memory map I/O on GBZ80 A[15:8] <= #1 8'hFF; end else if (Mode == 2 ) begin // Duplicate I/O address on 8080 A[15:8] <= #1 DI_Reg; end else begin A[15:8] <= #1 ACC; end A[7:0] <= #1 DI_Reg; end // case: aIOA aSP : begin A <= #1 SP; end aBC : begin if (Mode == 3 && iorq_i == 1'b1 ) begin // Memory map I/O on GBZ80 A[15:8] <= #1 8'hFF; A[7:0] <= #1 RegBusC[7:0]; end else begin A <= #1 RegBusC; end end // case: aBC aDE : begin A <= #1 RegBusC; end aZI : begin if (Inc_WZ == 1'b1 ) begin A <= #1 TmpAddr + 1; end else begin A[15:8] <= #1 DI_Reg; A[7:0] <= #1 TmpAddr[7:0]; end end // case: aZI default : begin A <= #1 PC; end endcase // case(Set_Addr_To) end // else: !if(mcycle == 3'b011 && IntCycle == 1'b1 && IStatus == 2'b10 ) Save_ALU_r <= #1 Save_ALU; ALU_Op_r <= #1 ALU_Op; if (I_CPL == 1'b1 ) begin // CPL ACC <= #1 ~ ACC; F[Flag_Y] <= #1 ~ ACC[5]; F[Flag_H] <= #1 1'b1; F[Flag_X] <= #1 ~ ACC[3]; F[Flag_N] <= #1 1'b1; end if (I_CCF == 1'b1 ) begin // CCF F[Flag_C] <= #1 ~ F[Flag_C]; F[Flag_Y] <= #1 ACC[5]; F[Flag_H] <= #1 F[Flag_C]; F[Flag_X] <= #1 ACC[3]; F[Flag_N] <= #1 1'b0; end if (I_SCF == 1'b1 ) begin // SCF F[Flag_C] <= #1 1'b1; F[Flag_Y] <= #1 ACC[5]; F[Flag_H] <= #1 1'b0; F[Flag_X] <= #1 ACC[3]; F[Flag_N] <= #1 1'b0; end end // if (T_Res == 1'b1 ) if (tstate == 2 && wait_n == 1'b1 ) begin if (ISet == 2'b01 && mcycle == 3'b111 ) begin IR <= #1 dinst; end if (JumpE == 1'b1 ) begin PC <= #1 PC16; end else if (Inc_PC == 1'b1 ) begin //PC <= #1 PC + 1; PC <= #1 PC16; end if (BTR_r == 1'b1 ) begin //PC <= #1 PC - 2; PC <= #1 PC16; end if (RstP == 1'b1 ) begin TmpAddr <= #1 { 10'h0, IR[5:3], 3'h0 }; //TmpAddr <= #1 (others =>1'b0); //TmpAddr[5:3] <= #1 IR[5:3]; end end if (tstate == 3 && mcycle == 3'b110 ) begin TmpAddr <= #1 SP16; end if ((tstate == 2 && wait_n == 1'b1) || (tstate == 4 && mcycle == 3'b001) ) begin if (IncDec_16[2:0] == 3'b111 ) begin SP <= #1 SP16; end end if (LDSPHL == 1'b1 ) begin SP <= #1 RegBusC; end if (ExchangeAF == 1'b1 ) begin Ap <= #1 ACC; ACC <= #1 Ap; Fp <= #1 F; F <= #1 Fp; end if (ExchangeRS == 1'b1 ) begin Alternate <= #1 ~ Alternate; end end // else: !if(mcycle == 3'b001 && tstate(2) == 1'b0 ) if (tstate == 3 ) begin if (LDZ == 1'b1 ) begin TmpAddr[7:0] <= #1 DI_Reg; end if (LDW == 1'b1 ) begin TmpAddr[15:8] <= #1 DI_Reg; end if (Special_LD[2] == 1'b1 ) begin case (Special_LD[1:0]) 2'b00 : begin ACC <= #1 I; F[Flag_P] <= #1 IntE_FF2; end 2'b01 : begin ACC <= #1 R; F[Flag_P] <= #1 IntE_FF2; end 2'b10 : I <= #1 ACC; default : R <= #1 ACC; endcase end end // if (tstate == 3 ) if ((I_DJNZ == 1'b0 && Save_ALU_r == 1'b1) || ALU_Op_r == 4'b1001 ) begin if (Mode == 3 ) begin F[6] <= #1 F_Out[6]; F[5] <= #1 F_Out[5]; F[7] <= #1 F_Out[7]; if (PreserveC_r == 1'b0 ) begin F[4] <= #1 F_Out[4]; end end else begin F[7:1] <= #1 F_Out[7:1]; if (PreserveC_r == 1'b0 ) begin F[Flag_C] <= #1 F_Out[0]; end end end // if ((I_DJNZ == 1'b0 && Save_ALU_r == 1'b1) || ALU_Op_r == 4'b1001 ) if (T_Res == 1'b1 && I_INRC == 1'b1 ) begin F[Flag_H] <= #1 1'b0; F[Flag_N] <= #1 1'b0; if (DI_Reg[7:0] == 8'b00000000 ) begin F[Flag_Z] <= #1 1'b1; end else begin F[Flag_Z] <= #1 1'b0; end F[Flag_S] <= #1 DI_Reg[7]; F[Flag_P] <= #1 ~ (^DI_Reg[7:0]); end // if (T_Res == 1'b1 && I_INRC == 1'b1 ) if (tstate == 1 && Auto_Wait_t1 == 1'b0 ) begin do <= #1 BusB; if (I_RLD == 1'b1 ) begin do[3:0] <= #1 BusA[3:0]; do[7:4] <= #1 BusB[3:0]; end if (I_RRD == 1'b1 ) begin do[3:0] <= #1 BusB[7:4]; do[7:4] <= #1 BusA[3:0]; end end if (T_Res == 1'b1 ) begin Read_To_Reg_r[3:0] <= #1 Set_BusA_To; Read_To_Reg_r[4] <= #1 Read_To_Reg; if (Read_To_Acc == 1'b1 ) begin Read_To_Reg_r[3:0] <= #1 4'b0111; Read_To_Reg_r[4] <= #1 1'b1; end end if (tstate == 1 && I_BT == 1'b1 ) begin F[Flag_X] <= #1 ALU_Q[3]; F[Flag_Y] <= #1 ALU_Q[1]; F[Flag_H] <= #1 1'b0; F[Flag_N] <= #1 1'b0; end if (I_BC == 1'b1 || I_BT == 1'b1 ) begin F[Flag_P] <= #1 IncDecZ; end if ((tstate == 1 && Save_ALU_r == 1'b0 && Auto_Wait_t1 == 1'b0) || (Save_ALU_r == 1'b1 && ALU_Op_r != 4'b0111) ) begin case (Read_To_Reg_r) 5'b10111 : ACC <= #1 Save_Mux; 5'b10110 : do <= #1 Save_Mux; 5'b11000 : SP[7:0] <= #1 Save_Mux; 5'b11001 : SP[15:8] <= #1 Save_Mux; 5'b11011 : F <= #1 Save_Mux; endcase end // if ((tstate == 1 && Save_ALU_r == 1'b0 && Auto_Wait_t1 == 1'b0) ||... end // if (ClkEn == 1'b1 ) end // else: !if(reset_n == 1'b0 ) end //------------------------------------------------------------------------- // // BC('), DE('), HL('), IX && IY // //------------------------------------------------------------------------- always @ (posedge clk) begin if (ClkEn == 1'b1 ) begin // Bus A / Write RegAddrA_r <= #1 { Alternate, Set_BusA_To[2:1] }; if (XY_Ind == 1'b0 && XY_State != 2'b00 && Set_BusA_To[2:1] == 2'b10 ) begin RegAddrA_r <= #1 { XY_State[1], 2'b11 }; end // Bus B RegAddrB_r <= #1 { Alternate, Set_BusB_To[2:1] }; if (XY_Ind == 1'b0 && XY_State != 2'b00 && Set_BusB_To[2:1] == 2'b10 ) begin RegAddrB_r <= #1 { XY_State[1], 2'b11 }; end // Address from register RegAddrC <= #1 { Alternate, Set_Addr_To[1:0] }; // Jump (HL), LD SP,HL if ((JumpXY == 1'b1 || LDSPHL == 1'b1) ) begin RegAddrC <= #1 { Alternate, 2'b10 }; end if (((JumpXY == 1'b1 || LDSPHL == 1'b1) && XY_State != 2'b00) || (mcycle == 3'b110) ) begin RegAddrC <= #1 { XY_State[1], 2'b11 }; end if (I_DJNZ == 1'b1 && Save_ALU_r == 1'b1 && Mode < 2 ) begin IncDecZ <= #1 F_Out[Flag_Z]; end if ((tstate == 2 || (tstate == 3 && mcycle == 3'b001)) && IncDec_16[2:0] == 3'b100 ) begin if (ID16 == 0 ) begin IncDecZ <= #1 1'b0; end else begin IncDecZ <= #1 1'b1; end end RegBusA_r <= #1 RegBusA; end end // always @ (posedge clk) always @(/*AUTOSENSE*/Alternate or ExchangeDH or IncDec_16 or RegAddrA_r or RegAddrB_r or XY_State or mcycle or tstate) begin if ((tstate == 2 || (tstate == 3 && mcycle == 3'b001 && IncDec_16[2] == 1'b1)) && XY_State == 2'b00) RegAddrA = { Alternate, IncDec_16[1:0] }; else if ((tstate == 2 || (tstate == 3 && mcycle == 3'b001 && IncDec_16[2] == 1'b1)) && IncDec_16[1:0] == 2'b10) RegAddrA = { XY_State[1], 2'b11 }; else if (ExchangeDH == 1'b1 && tstate == 3) RegAddrA = { Alternate, 2'b10 }; else if (ExchangeDH == 1'b1 && tstate == 4) RegAddrA = { Alternate, 2'b01 }; else RegAddrA = RegAddrA_r; if (ExchangeDH == 1'b1 && tstate == 3) RegAddrB = { Alternate, 2'b01 }; else RegAddrB = RegAddrB_r; end // always @ * always @(/*AUTOSENSE*/ALU_Op_r or Auto_Wait_t1 or ExchangeDH or IncDec_16 or Read_To_Reg_r or Save_ALU_r or mcycle or tstate or wait_n) begin RegWEH = 1'b0; RegWEL = 1'b0; if ((tstate == 1 && Save_ALU_r == 1'b0 && Auto_Wait_t1 == 1'b0) || (Save_ALU_r == 1'b1 && ALU_Op_r != 4'b0111) ) begin case (Read_To_Reg_r) 5'b10000 , 5'b10001 , 5'b10010 , 5'b10011 , 5'b10100 , 5'b10101 : begin RegWEH = ~ Read_To_Reg_r[0]; RegWEL = Read_To_Reg_r[0]; end endcase // case(Read_To_Reg_r) end // if ((tstate == 1 && Save_ALU_r == 1'b0 && Auto_Wait_t1 == 1'b0) ||... if (ExchangeDH == 1'b1 && (tstate == 3 || tstate == 4) ) begin RegWEH = 1'b1; RegWEL = 1'b1; end if (IncDec_16[2] == 1'b1 && ((tstate == 2 && wait_n == 1'b1 && mcycle != 3'b001) || (tstate == 3 && mcycle == 3'b001)) ) begin case (IncDec_16[1:0]) 2'b00 , 2'b01 , 2'b10 : begin RegWEH = 1'b1; RegWEL = 1'b1; end endcase end end // always @ * always @(/*AUTOSENSE*/ExchangeDH or ID16 or IncDec_16 or RegBusA_r or RegBusB or Save_Mux or mcycle or tstate) begin RegDIH = Save_Mux; RegDIL = Save_Mux; if (ExchangeDH == 1'b1 && tstate == 3 ) begin RegDIH = RegBusB[15:8]; RegDIL = RegBusB[7:0]; end else if (ExchangeDH == 1'b1 && tstate == 4 ) begin RegDIH = RegBusA_r[15:8]; RegDIL = RegBusA_r[7:0]; end else if (IncDec_16[2] == 1'b1 && ((tstate == 2 && mcycle != 3'b001) || (tstate == 3 && mcycle == 3'b001)) ) begin RegDIH = ID16[15:8]; RegDIL = ID16[7:0]; end end tv80_reg i_reg ( .clk (clk), .CEN (ClkEn), .WEH (RegWEH), .WEL (RegWEL), .AddrA (RegAddrA), .AddrB (RegAddrB), .AddrC (RegAddrC), .DIH (RegDIH), .DIL (RegDIL), .DOAH (RegBusA[15:8]), .DOAL (RegBusA[7:0]), .DOBH (RegBusB[15:8]), .DOBL (RegBusB[7:0]), .DOCH (RegBusC[15:8]), .DOCL (RegBusC[7:0]) ); //------------------------------------------------------------------------- // // Buses // //------------------------------------------------------------------------- always @ (posedge clk) begin if (ClkEn == 1'b1 ) begin case (Set_BusB_To) 4'b0111 : BusB <= #1 ACC; 4'b0000 , 4'b0001 , 4'b0010 , 4'b0011 , 4'b0100 , 4'b0101 : begin if (Set_BusB_To[0] == 1'b1 ) begin BusB <= #1 RegBusB[7:0]; end else begin BusB <= #1 RegBusB[15:8]; end end 4'b0110 : BusB <= #1 DI_Reg; 4'b1000 : BusB <= #1 SP[7:0]; 4'b1001 : BusB <= #1 SP[15:8]; 4'b1010 : BusB <= #1 8'b00000001; 4'b1011 : BusB <= #1 F; 4'b1100 : BusB <= #1 PC[7:0]; 4'b1101 : BusB <= #1 PC[15:8]; 4'b1110 : BusB <= #1 8'b00000000; default : BusB <= #1 8'hxx; endcase case (Set_BusA_To) 4'b0111 : BusA <= #1 ACC; 4'b0000 , 4'b0001 , 4'b0010 , 4'b0011 , 4'b0100 , 4'b0101 : begin if (Set_BusA_To[0] == 1'b1 ) begin BusA <= #1 RegBusA[7:0]; end else begin BusA <= #1 RegBusA[15:8]; end end 4'b0110 : BusA <= #1 DI_Reg; 4'b1000 : BusA <= #1 SP[7:0]; 4'b1001 : BusA <= #1 SP[15:8]; 4'b1010 : BusA <= #1 8'b00000000; default : BusB <= #1 8'hxx; endcase end end //------------------------------------------------------------------------- // // Generate external control signals // //------------------------------------------------------------------------- always @ (posedge clk) begin if (reset_n == 1'b0 ) begin rfsh_n <= #1 1'b1; end else begin if (cen == 1'b1 ) begin if (mcycle == 3'b001 && ((tstate == 2 && wait_n == 1'b1) || tstate == 3) ) begin rfsh_n <= #1 1'b0; end else begin rfsh_n <= #1 1'b1; end end end end always @(/*AUTOSENSE*/BusAck or Halt_FF or I_DJNZ or IntCycle or IntE_FF1 or di or iorq_i or mcycle or tstate) begin mc = mcycle; ts = tstate; DI_Reg = di; halt_n = ~ Halt_FF; busak_n = ~ BusAck; intcycle_n = ~ IntCycle; IntE = IntE_FF1; iorq = iorq_i; stop = I_DJNZ; end //----------------------------------------------------------------------- // // Syncronise inputs // //----------------------------------------------------------------------- always @ (posedge clk) begin : sync_inputs if (reset_n == 1'b0 ) begin BusReq_s <= #1 1'b0; INT_s <= #1 1'b0; NMI_s <= #1 1'b0; Oldnmi_n <= #1 1'b0; end else begin if (cen == 1'b1 ) begin BusReq_s <= #1 ~ busrq_n; INT_s <= #1 ~ int_n; if (NMICycle == 1'b1 ) begin NMI_s <= #1 1'b0; end else if (nmi_n == 1'b0 && Oldnmi_n == 1'b1 ) begin NMI_s <= #1 1'b1; end Oldnmi_n <= #1 nmi_n; end end end //----------------------------------------------------------------------- // // Main state machine // //----------------------------------------------------------------------- always @ (posedge clk) begin if (reset_n == 1'b0 ) begin mcycle <= #1 3'b001; tstate <= #1 3'b000; Pre_XY_F_M <= #1 3'b000; Halt_FF <= #1 1'b0; BusAck <= #1 1'b0; NMICycle <= #1 1'b0; IntCycle <= #1 1'b0; IntE_FF1 <= #1 1'b0; IntE_FF2 <= #1 1'b0; No_BTR <= #1 1'b0; Auto_Wait_t1 <= #1 1'b0; Auto_Wait_t2 <= #1 1'b0; m1_n <= #1 1'b1; end else begin if (cen == 1'b1 ) begin if (T_Res == 1'b1 ) begin Auto_Wait_t1 <= #1 1'b0; end else begin Auto_Wait_t1 <= #1 Auto_Wait || iorq_i; end Auto_Wait_t2 <= #1 Auto_Wait_t1; No_BTR <= #1 (I_BT && (~ IR[4] || ~ F[Flag_P])) || (I_BC && (~ IR[4] || F[Flag_Z] || ~ F[Flag_P])) || (I_BTR && (~ IR[4] || F[Flag_Z])); if (tstate == 2 ) begin if (SetEI == 1'b1 ) begin IntE_FF1 <= #1 1'b1; IntE_FF2 <= #1 1'b1; end if (I_RETN == 1'b1 ) begin IntE_FF1 <= #1 IntE_FF2; end end if (tstate == 3 ) begin if (SetDI == 1'b1 ) begin IntE_FF1 <= #1 1'b0; IntE_FF2 <= #1 1'b0; end end if (IntCycle == 1'b1 || NMICycle == 1'b1 ) begin Halt_FF <= #1 1'b0; end if (mcycle == 3'b001 && tstate == 2 && wait_n == 1'b1 ) begin m1_n <= #1 1'b1; end if (BusReq_s == 1'b1 && BusAck == 1'b1 ) begin end else begin BusAck <= #1 1'b0; if (tstate == 2 && wait_n == 1'b0 ) begin end else if (T_Res == 1'b1 ) begin if (Halt == 1'b1 ) begin Halt_FF <= #1 1'b1; end if (BusReq_s == 1'b1 ) begin BusAck <= #1 1'b1; end else begin tstate <= #1 3'b001; if (NextIs_XY_Fetch == 1'b1 ) begin mcycle <= #1 3'b110; Pre_XY_F_M <= #1 mcycle; if (IR == 8'b00110110 && Mode == 0 ) begin Pre_XY_F_M <= #1 3'b010; end end else if ((mcycle == 3'b111) || (mcycle == 3'b110 && Mode == 1 && ISet != 2'b01) ) begin mcycle <= #1 Pre_XY_F_M + 1; end else if ((mcycle == mcycles) || No_BTR == 1'b1 || (mcycle == 3'b010 && I_DJNZ == 1'b1 && IncDecZ == 1'b1) ) begin m1_n <= #1 1'b0; mcycle <= #1 3'b001; IntCycle <= #1 1'b0; NMICycle <= #1 1'b0; if (NMI_s == 1'b1 && Prefix == 2'b00 ) begin NMICycle <= #1 1'b1; IntE_FF1 <= #1 1'b0; end else if ((IntE_FF1 == 1'b1 && INT_s == 1'b1) && Prefix == 2'b00 && SetEI == 1'b0 ) begin IntCycle <= #1 1'b1; IntE_FF1 <= #1 1'b0; IntE_FF2 <= #1 1'b0; end end else begin mcycle <= #1 mcycle + 1; end end end else begin // verilog has no "nor" operator if ( ~(Auto_Wait == 1'b1 && Auto_Wait_t2 == 1'b0) && ~(IOWait == 1 && iorq_i == 1'b1 && Auto_Wait_t1 == 1'b0) ) begin tstate <= #1 tstate + 1; end end end if (tstate == 0 ) begin m1_n <= #1 1'b0; end end end end always @(/*AUTOSENSE*/BTR_r or DI_Reg or IncDec_16 or JumpE or PC or RegBusA or RegBusC or SP or tstate) begin if (JumpE == 1'b1 ) begin PC16_B = { {8{DI_Reg[7]}}, DI_Reg }; end else if (BTR_r == 1'b1 ) begin PC16_B = -2; end else begin PC16_B = 1; end if (tstate == 3) begin SP16_A = RegBusC; SP16_B = { {8{DI_Reg[7]}}, DI_Reg }; end else begin // suspect that ID16 and SP16 could be shared SP16_A = SP; if (IncDec_16[3] == 1'b1) SP16_B = -1; else SP16_B = 1; end if (IncDec_16[3]) ID16_B = -1; else ID16_B = 1; ID16 = RegBusA + ID16_B; PC16 = PC + PC16_B; SP16 = SP16_A + SP16_B; end // always @ * always @(/*AUTOSENSE*/IntCycle or NMICycle or mcycle) begin Auto_Wait = 1'b0; if (IntCycle == 1'b1 || NMICycle == 1'b1 ) begin if (mcycle == 3'b001 ) begin Auto_Wait = 1'b1; end end end // always @ * // synopsys dc_script_begin // set_attribute current_design "revision" "$Id: tv80_core.v,v 1.1 2004-05-16 17:39:57 ghutchis Exp $" -type string -quiet // synopsys dc_script_end endmodule // T80
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