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robfinch |
// ============================================================================
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// __
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// \\__/ o\ (C) 2013 Robert Finch, Stratford
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// \ __ / All rights reserved.
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// \/_// robfinch<remove>@opencores.org
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// ||
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//
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// This source file is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published
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// by the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This source file is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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//
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// ============================================================================
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//
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DECODE:
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begin
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first_ifetch <= `TRUE;
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Rt <= 4'h0; // Default
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state <= IFETCH;
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case(ir[7:0])
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`STP: begin clk_en <= 1'b0; pc <= pc + 32'd1; end
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`NOP: begin pc <= pc + 32'd1; end
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`CLC: begin cf <= 1'b0; pc <= pc + 32'd1; end
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`SEC: begin cf <= 1'b1; pc <= pc + 32'd1; end
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`CLV: begin vf <= 1'b0; pc <= pc + 32'd1; end
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`CLI: begin im <= 1'b0; pc <= pc + 32'd1; end
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`CLD: begin df <= 1'b0; pc <= pc + 32'd1; end
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`SED: begin df <= 1'b1; pc <= pc + 32'd1; end
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`SEI: begin im <= 1'b1; pc <= pc + 32'd1; end
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`WAI: begin wai <= 1'b1; pc <= pc + 32'd1; end
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`EMM: begin em <= 1'b1; pc <= pc + 32'd1; end
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`DEX: begin res <= x - 32'd1; pc <= pc + 32'd1; end
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`INX: begin res <= x + 32'd1; pc <= pc + 32'd1; end
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`DEY: begin res <= y - 32'd1; pc <= pc + 32'd1; end
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`INY: begin res <= y + 32'd1; pc <= pc + 32'd1; end
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`DEA: begin res <= acc - 32'd1; pc <= pc + 32'd1; end
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`INA: begin res <= acc + 32'd1; pc <= pc + 32'd1; end
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`TSX: begin res <= isp; pc <= pc + 32'd1; end
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`TXS,`TXA,`TXY: begin res <= x; pc <= pc + 32'd1; end
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`TAX,`TAY,`TAS: begin res <= acc; pc <= pc + 32'd1; end
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`TYA,`TYX: begin res <= y; pc <= pc + 32'd1; end
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`TRS: begin
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res <= rfoa; pc <= pc + 32'd2; end
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`TSR: begin
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Rt <= ir[15:12];
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case(ir[11:8])
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4'h0: res <= {write_allocate,dcacheOn,icacheOn};
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4'h1: res <= dp;
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4'h2: res <= prod[31:0];
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4'h3: res <= prod[63:32];
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4'h4: res <= tick;
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4'h5: begin res <= lfsr; lfsr <= {lfsr[30:0],lfsr_fb}; end
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4'h6: res <= dp8;
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4'h7: res <= abs8;
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4'h8: res <= {vbr[31:1],nmoi};
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4'hE: res <= {spage[31:8],sp};
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4'hF: res <= isp;
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endcase
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pc <= pc + 32'd2;
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end
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`ASL_ACC: begin res <= {acc,1'b0}; pc <= pc + 32'd1; end
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`ROL_ACC: begin res <= {acc,cf}; pc <= pc + 32'd1; end
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`LSR_ACC: begin res <= {acc[0],1'b0,acc[31:1]}; pc <= pc + 32'd1; end
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`ROR_ACC: begin res <= {acc[0],cf,acc[31:1]}; pc <= pc + 32'd1; end
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`RR:
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begin
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state <= IFETCH;
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case(ir[23:20])
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`ADD_RR: begin res <= rfoa + rfob; a <= rfoa; b <= rfob; end
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`SUB_RR: begin res <= rfoa - rfob; a <= rfoa; b <= rfob; end
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`AND_RR: begin res <= rfoa & rfob; a <= rfoa; b <= rfob; end // for bit flags
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`OR_RR: begin res <= rfoa | rfob; a <= rfoa; b <= rfob; end
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`EOR_RR: begin res <= rfoa ^ rfob; a <= rfoa; b <= rfob; end
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`MUL_RR: begin state <= MULDIV1; end
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`MULS_RR: begin state <= MULDIV1; end
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`DIV_RR: begin state <= MULDIV1; end
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`DIVS_RR: begin state <= MULDIV1; end
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`MOD_RR: begin state <= MULDIV1; end
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`MODS_RR: begin state <= MULDIV1; end
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`ASL_RRR: begin a <= rfoa; b <= rfob; state <= CALC; end
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`LSR_RRR: begin a <= rfoa; b <= rfob; state <= CALC; end
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endcase
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Rt <= ir[19:16];
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pc <= pc + 32'd3;
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end
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`LD_RR: begin res <= rfoa; Rt <= ir[15:12]; pc <= pc + 32'd2; end
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`ASL_RR: begin res <= {rfoa,1'b0}; pc <= pc + 32'd2; Rt <= ir[15:12]; end
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`ROL_RR: begin res <= {rfoa,cf}; pc <= pc + 32'd2; Rt <= ir[15:12]; end
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`LSR_RR: begin res <= {rfoa[0],1'b0,rfoa[31:1]}; pc <= pc + 32'd2; Rt <= ir[15:12]; end
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`ROR_RR: begin res <= {rfoa[0],cf,rfoa[31:1]}; pc <= pc + 32'd2; Rt <= ir[15:12]; end
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`DEC_RR: begin res <= rfoa - 32'd1; pc <= pc + 32'd2; Rt <= ir[15:12]; end
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`INC_RR: begin res <= rfoa + 32'd1; pc <= pc + 32'd2; Rt <= ir[15:12]; end
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`ADD_IMM8: begin res <= rfoa + {{24{ir[23]}},ir[23:16]}; Rt <= ir[15:12]; pc <= pc + 32'd3; a <= rfoa; b <= {{24{ir[23]}},ir[23:16]}; end
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`SUB_IMM8: begin res <= rfoa - {{24{ir[23]}},ir[23:16]}; Rt <= ir[15:12]; pc <= pc + 32'd3; a <= rfoa; b <= {{24{ir[23]}},ir[23:16]}; end
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`OR_IMM8: begin res <= rfoa | {{24{ir[23]}},ir[23:16]}; Rt <= ir[15:12]; pc <= pc + 32'd3; b <= {{24{ir[23]}},ir[23:16]}; end
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`AND_IMM8: begin res <= rfoa & {{24{ir[23]}},ir[23:16]}; Rt <= ir[15:12]; pc <= pc + 32'd3; b <= {{24{ir[23]}},ir[23:16]}; end
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`EOR_IMM8: begin res <= rfoa ^ {{24{ir[23]}},ir[23:16]}; Rt <= ir[15:12]; pc <= pc + 32'd3; b <= {{24{ir[23]}},ir[23:16]}; end
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`CMP_IMM8: begin res <= acc - {{24{ir[15]}},ir[15:8]}; Rt <= 4'h0; pc <= pc + 32'd2; b <= {{24{ir[15]}},ir[15:8]}; end
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`ASL_IMM8: begin a <= rfoa; b <= ir[20:16]; Rt <= ir[15:12]; pc <= pc + 32'd3; state <= CALC; end
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`LSR_IMM8: begin a <= rfoa; b <= ir[20:16]; Rt <= ir[15:12]; pc <= pc + 32'd3; state <= CALC; end
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`ADD_IMM16: begin res <= rfoa + {{16{ir[31]}},ir[31:16]}; Rt <= ir[15:12]; pc <= pc + 32'd4; a <= rfoa; b <= {{16{ir[31]}},ir[31:16]}; end
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`SUB_IMM16: begin res <= rfoa - {{16{ir[31]}},ir[31:16]}; Rt <= ir[15:12]; pc <= pc + 32'd4; a <= rfoa; b <= {{16{ir[31]}},ir[31:16]}; end
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`OR_IMM16: begin res <= rfoa | {{16{ir[31]}},ir[31:16]}; Rt <= ir[15:12]; pc <= pc + 32'd4; b <= {{16{ir[31]}},ir[31:16]}; end
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`AND_IMM16: begin res <= rfoa & {{16{ir[31]}},ir[31:16]}; Rt <= ir[15:12]; pc <= pc + 32'd4; b <= {{16{ir[31]}},ir[31:16]}; end
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`EOR_IMM16: begin res <= rfoa ^ {{16{ir[31]}},ir[31:16]}; Rt <= ir[15:12]; pc <= pc + 32'd4; b <= {{16{ir[31]}},ir[31:16]}; end
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`ADD_IMM32: begin res <= rfoa + ir[47:16]; Rt <= ir[15:12]; pc <= pc + 32'd6; a <= rfoa; b <= ir[47:16]; end
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`SUB_IMM32: begin res <= rfoa - ir[47:16]; Rt <= ir[15:12]; pc <= pc + 32'd6; a <= rfoa; b <= ir[47:16]; end
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`OR_IMM32: begin res <= rfoa | ir[47:16]; Rt <= ir[15:12]; pc <= pc + 32'd6; b <= ir[47:16]; end
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`AND_IMM32: begin res <= rfoa & ir[47:16]; Rt <= ir[15:12]; pc <= pc + 32'd6; b <= ir[47:16]; end
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`EOR_IMM32: begin res <= rfoa ^ ir[47:16]; Rt <= ir[15:12]; pc <= pc + 32'd6; b <= ir[47:16]; end
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`LDX_IMM32,`LDY_IMM32,`LDA_IMM32: begin res <= ir[39:8]; pc <= pc + 32'd5; end
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`LDX_IMM16,`LDA_IMM16: begin res <= {{16{ir[23]}},ir[23:8]}; pc <= pc + 32'd3; end
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`LDX_IMM8,`LDA_IMM8: begin res <= {{24{ir[15]}},ir[15:8]}; pc <= pc + 32'd2; end
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`LDX_ZPX,`LDY_ZPX:
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begin
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radr <= zpx32xy_address;
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pc <= pc + 32'd3;
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state <= LOAD1;
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end
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`ORB_ZPX:
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begin
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a <= rfoa;
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Rt <= ir[19:16];
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radr <= zpx32_address[31:2];
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radr2LSB <= zpx32_address[1:0];
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pc <= pc + 32'd4;
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state <= LOAD1;
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end
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`LDX_ABS,`LDY_ABS:
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begin
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radr <= ir[39:8];
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pc <= pc + 32'd5;
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state <= LOAD1;
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end
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`ORB_ABS:
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begin
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a <= rfoa;
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Rt <= ir[15:12];
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radr <= ir[47:18];
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radr2LSB <= ir[17:16];
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pc <= pc + 32'd6;
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state <= LOAD1;
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end
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`LDX_ABSY,`LDY_ABSX:
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begin
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radr <= absx32xy_address;
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pc <= pc + 32'd6;
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state <= LOAD1;
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end
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`ORB_ABSX:
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begin
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a <= rfoa;
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Rt <= ir[19:16];
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radr <= absx32_address[31:2];
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radr2LSB <= absx32_address[1:0];
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pc <= pc + 32'd7;
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state <= LOAD1;
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end
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`ST_ZPX:
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begin
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wadr <= zpx32_address;
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wdat <= rfoa;
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pc <= pc + 32'd4;
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state <= STORE1;
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end
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`STB_ZPX:
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begin
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wadr <= zpx32_address[31:2];
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wadr2LSB <= zpx32_address[1:0];
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pc <= pc + 32'd4;
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state <= STORE1;
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end
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`ST_ABS:
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begin
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wadr <= ir[47:16];
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wdat <= rfoa;
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pc <= pc + 32'd6;
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state <= STORE1;
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end
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`STB_ABS:
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begin
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wadr <= ir[47:18];
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wadr2LSB <= ir[17:16];
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wdat <= {4{rfoa[7:0]}};
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pc <= pc + 32'd6;
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state <= STORE1;
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end
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`ST_ABSX:
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begin
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wadr <= absx32_address;
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wdat <= rfoa;
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pc <= pc + 32'd7;
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state <= STORE1;
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end
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`STB_ABSX:
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begin
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wadr <= absx32_address[31:2];
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wadr2LSB <= absx32_address[1:0];
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wdat <= {4{rfoa[7:0]}};
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pc <= pc + 32'd7;
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state <= STORE1;
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end
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`STX_ZPX:
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begin
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| 219 |
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wadr <= dp + ir[23:12] + rfoa;
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wdat <= x;
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| 221 |
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pc <= pc + 32'd3;
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| 222 |
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state <= STORE1;
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end
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`STX_ABS:
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begin
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| 226 |
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wadr <= ir[39:8];
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| 227 |
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wdat <= x;
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| 228 |
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pc <= pc + 32'd5;
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state <= STORE1;
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end
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`STY_ZPX:
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| 232 |
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begin
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| 233 |
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wadr <= dp + ir[23:12] + rfoa;
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| 234 |
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wdat <= y;
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| 235 |
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pc <= pc + 32'd3;
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state <= STORE1;
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end
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| 238 |
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`STY_ABS:
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| 239 |
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begin
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| 240 |
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wadr <= ir[39:8];
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| 241 |
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wdat <= y;
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| 242 |
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pc <= pc + 32'd5;
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| 243 |
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state <= STORE1;
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| 244 |
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end
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| 245 |
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`ADD_ZPX,`SUB_ZPX,`OR_ZPX,`AND_ZPX,`EOR_ZPX:
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| 246 |
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begin
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| 247 |
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a <= rfoa;
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| 248 |
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Rt <= ir[19:16];
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| 249 |
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radr <= zpx32_address;
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| 250 |
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pc <= pc + 32'd4;
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| 251 |
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state <= LOAD1;
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| 252 |
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end
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| 253 |
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`ASL_ZPX,`ROL_ZPX,`LSR_ZPX,`ROR_ZPX,`INC_ZPX,`DEC_ZPX:
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| 254 |
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begin
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| 255 |
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radr <= dp + rfoa + ir[23:12];
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| 256 |
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pc <= pc + 32'd3;
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| 257 |
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state <= LOAD1;
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| 258 |
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end
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| 259 |
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`ADD_IX,`SUB_IX,`OR_IX,`AND_IX,`EOR_IX,`ST_IX:
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| 260 |
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begin
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| 261 |
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a <= rfoa;
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| 262 |
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if (ir[7:0]==`ST_IX)
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| 263 |
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res <= rfoa; // for ST_IX, Rt=0
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| 264 |
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else
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| 265 |
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Rt <= ir[19:16];
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| 266 |
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pc <= pc + 32'd4;
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| 267 |
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radr <= dp + ir[31:20] + rfob;
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| 268 |
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state <= IX1;
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| 269 |
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end
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| 270 |
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`ADD_RIND,`SUB_RIND,`OR_RIND,`AND_RIND,`EOR_RIND,`ST_RIND:
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| 271 |
|
|
begin
|
| 272 |
|
|
radr <= rfob;
|
| 273 |
|
|
wadr <= rfob; // for store
|
| 274 |
|
|
wdat <= rfoa;
|
| 275 |
|
|
a <= rfoa;
|
| 276 |
|
|
if (ir[7:0]==`ST_RIND) begin
|
| 277 |
|
|
res <= rfoa; // for ST_IX, Rt=0
|
| 278 |
|
|
pc <= pc + 32'd2;
|
| 279 |
|
|
state <= STORE1;
|
| 280 |
|
|
end
|
| 281 |
|
|
else begin
|
| 282 |
|
|
Rt <= ir[19:16];
|
| 283 |
|
|
pc <= pc + 32'd3;
|
| 284 |
|
|
state <= LOAD1;
|
| 285 |
|
|
end
|
| 286 |
|
|
end
|
| 287 |
|
|
`ADD_IY,`SUB_IY,`OR_IY,`AND_IY,`EOR_IY,`ST_IY:
|
| 288 |
|
|
begin
|
| 289 |
|
|
a <= rfoa;
|
| 290 |
|
|
if (ir[7:0]==`ST_IY)
|
| 291 |
|
|
res <= rfoa; // for ST_IY, Rt=0
|
| 292 |
|
|
else
|
| 293 |
|
|
Rt <= ir[19:16];
|
| 294 |
|
|
pc <= pc + 32'd4;
|
| 295 |
|
|
radr <= dp + ir[31:20];
|
| 296 |
|
|
state <= IY1;
|
| 297 |
|
|
end
|
| 298 |
|
|
`ADD_ABS,`SUB_ABS,`OR_ABS,`AND_ABS,`EOR_ABS:
|
| 299 |
|
|
begin
|
| 300 |
|
|
a <= rfoa;
|
| 301 |
|
|
radr <= ir[47:16];
|
| 302 |
|
|
Rt <= ir[15:12];
|
| 303 |
|
|
pc <= pc + 32'd6;
|
| 304 |
|
|
state <= LOAD1;
|
| 305 |
|
|
end
|
| 306 |
|
|
`ASL_ABS,`ROL_ABS,`LSR_ABS,`ROR_ABS,`INC_ABS,`DEC_ABS:
|
| 307 |
|
|
begin
|
| 308 |
|
|
radr <= ir[39:8];
|
| 309 |
|
|
pc <= pc + 32'd5;
|
| 310 |
|
|
state <= LOAD1;
|
| 311 |
|
|
end
|
| 312 |
|
|
`ADD_ABSX,`SUB_ABSX,`OR_ABSX,`AND_ABSX,`EOR_ABSX:
|
| 313 |
|
|
begin
|
| 314 |
|
|
a <= rfoa;
|
| 315 |
|
|
radr <= ir[55:24] + rfob;
|
| 316 |
|
|
Rt <= ir[19:16];
|
| 317 |
|
|
pc <= pc + 32'd7;
|
| 318 |
|
|
state <= LOAD1;
|
| 319 |
|
|
end
|
| 320 |
|
|
`ASL_ABSX,`ROL_ABSX,`LSR_ABSX,`ROR_ABSX,`INC_ABSX,`DEC_ABSX:
|
| 321 |
|
|
begin
|
| 322 |
|
|
radr <= ir[47:16] + rfob;
|
| 323 |
|
|
pc <= pc + 32'd6;
|
| 324 |
|
|
state <= LOAD1;
|
| 325 |
|
|
end
|
| 326 |
|
|
`CPX_IMM32:
|
| 327 |
|
|
begin
|
| 328 |
|
|
res <= x - ir[39:8];
|
| 329 |
|
|
pc <= pc + 32'd5;
|
| 330 |
|
|
state <= IFETCH;
|
| 331 |
|
|
end
|
| 332 |
|
|
`CPY_IMM32:
|
| 333 |
|
|
begin
|
| 334 |
|
|
res <= y - ir[39:8];
|
| 335 |
|
|
pc <= pc + 32'd5;
|
| 336 |
|
|
state <= IFETCH;
|
| 337 |
|
|
end
|
| 338 |
|
|
`CPX_ZPX:
|
| 339 |
|
|
begin
|
| 340 |
|
|
radr <= dp + ir[23:12] + rfoa;
|
| 341 |
|
|
pc <= pc + 32'd3;
|
| 342 |
|
|
state <= LOAD1;
|
| 343 |
|
|
end
|
| 344 |
|
|
`CPY_ZPX:
|
| 345 |
|
|
begin
|
| 346 |
|
|
radr <= dp + ir[23:12] + rfoa;
|
| 347 |
|
|
pc <= pc + 32'd3;
|
| 348 |
|
|
state <= LOAD1;
|
| 349 |
|
|
end
|
| 350 |
|
|
`CPX_ABS:
|
| 351 |
|
|
begin
|
| 352 |
|
|
radr <= ir[39:8];
|
| 353 |
|
|
pc <= pc + 32'd5;
|
| 354 |
|
|
state <= LOAD1;
|
| 355 |
|
|
end
|
| 356 |
|
|
`CPY_ABS:
|
| 357 |
|
|
begin
|
| 358 |
|
|
radr <= ir[39:8];
|
| 359 |
|
|
pc <= pc + 32'd5;
|
| 360 |
|
|
state <= LOAD1;
|
| 361 |
|
|
end
|
| 362 |
|
|
`BRK:
|
| 363 |
|
|
begin
|
| 364 |
|
|
bf <= 1'b1;
|
| 365 |
|
|
radr <= isp_dec;
|
| 366 |
|
|
wadr <= isp_dec;
|
| 367 |
|
|
wdat <= pc + 32'd1;
|
| 368 |
|
|
cyc_o <= 1'b1;
|
| 369 |
|
|
stb_o <= 1'b1;
|
| 370 |
|
|
we_o <= 1'b1;
|
| 371 |
|
|
sel_o <= 4'hF;
|
| 372 |
|
|
adr_o <= {isp_dec,2'b00};
|
| 373 |
|
|
dat_o <= pc + 32'd1;
|
| 374 |
|
|
vect <= {vbr[31:9],`BRK_VECTNO,2'b00};
|
| 375 |
|
|
state <= IRQ1;
|
| 376 |
|
|
end
|
| 377 |
|
|
`JMP:
|
| 378 |
|
|
begin
|
| 379 |
|
|
pc[15:0] <= ir[23:8];
|
| 380 |
|
|
state <= IFETCH;
|
| 381 |
|
|
end
|
| 382 |
|
|
`JML:
|
| 383 |
|
|
begin
|
| 384 |
|
|
pc <= ir[39:8];
|
| 385 |
|
|
state <= IFETCH;
|
| 386 |
|
|
end
|
| 387 |
|
|
`JMP_IND:
|
| 388 |
|
|
begin
|
| 389 |
|
|
radr <= ir[39:8];
|
| 390 |
|
|
state <= JMP_IND1;
|
| 391 |
|
|
end
|
| 392 |
|
|
`JMP_INDX:
|
| 393 |
|
|
begin
|
| 394 |
|
|
radr <= ir[39:8] + x;
|
| 395 |
|
|
state <= JMP_IND1;
|
| 396 |
|
|
end
|
| 397 |
|
|
`JMP_RIND:
|
| 398 |
|
|
begin
|
| 399 |
|
|
pc <= rfoa;
|
| 400 |
|
|
res <= pc + 32'd2;
|
| 401 |
|
|
Rt <= ir[15:12];
|
| 402 |
|
|
state <= IFETCH;
|
| 403 |
|
|
end
|
| 404 |
|
|
`JSR:
|
| 405 |
|
|
begin
|
| 406 |
|
|
radr <= isp_dec;
|
| 407 |
|
|
wadr <= isp_dec;
|
| 408 |
|
|
wdat <= pc + 32'd3;
|
| 409 |
|
|
cyc_o <= 1'b1;
|
| 410 |
|
|
stb_o <= 1'b1;
|
| 411 |
|
|
we_o <= 1'b1;
|
| 412 |
|
|
sel_o <= 4'hF;
|
| 413 |
|
|
adr_o <= {isp_dec,2'b00};
|
| 414 |
|
|
dat_o <= pc + 32'd3;
|
| 415 |
|
|
vect <= {pc[31:16],ir[23:8]};
|
| 416 |
|
|
state <= JSR1;
|
| 417 |
|
|
end
|
| 418 |
|
|
`JSR_RIND:
|
| 419 |
|
|
begin
|
| 420 |
|
|
radr <= isp_dec;
|
| 421 |
|
|
wadr <= isp_dec;
|
| 422 |
|
|
wdat <= pc + 32'd2;
|
| 423 |
|
|
cyc_o <= 1'b1;
|
| 424 |
|
|
stb_o <= 1'b1;
|
| 425 |
|
|
we_o <= 1'b1;
|
| 426 |
|
|
sel_o <= 4'hF;
|
| 427 |
|
|
adr_o <= {isp_dec,2'b00};
|
| 428 |
|
|
dat_o <= pc + 32'd2;
|
| 429 |
|
|
vect <= rfoa;
|
| 430 |
|
|
state <= JSR1;
|
| 431 |
|
|
$stop;
|
| 432 |
|
|
end
|
| 433 |
|
|
`JSL:
|
| 434 |
|
|
begin
|
| 435 |
|
|
radr <= isp_dec;
|
| 436 |
|
|
wadr <= isp_dec;
|
| 437 |
|
|
wdat <= pc + 32'd5;
|
| 438 |
|
|
cyc_o <= 1'b1;
|
| 439 |
|
|
stb_o <= 1'b1;
|
| 440 |
|
|
we_o <= 1'b1;
|
| 441 |
|
|
sel_o <= 4'hF;
|
| 442 |
|
|
adr_o <= {isp_dec,2'b00};
|
| 443 |
|
|
dat_o <= pc + 32'd5;
|
| 444 |
|
|
vect <= ir[39:8];
|
| 445 |
|
|
state <= JSR1;
|
| 446 |
|
|
end
|
| 447 |
|
|
`BSR:
|
| 448 |
|
|
begin
|
| 449 |
|
|
radr <= isp_dec;
|
| 450 |
|
|
wadr <= isp_dec;
|
| 451 |
|
|
wdat <= pc + 32'd3;
|
| 452 |
|
|
cyc_o <= 1'b1;
|
| 453 |
|
|
stb_o <= 1'b1;
|
| 454 |
|
|
we_o <= 1'b1;
|
| 455 |
|
|
sel_o <= 4'hF;
|
| 456 |
|
|
adr_o <= {isp_dec,2'b00};
|
| 457 |
|
|
dat_o <= pc + 32'd3;
|
| 458 |
|
|
vect <= pc + {{16{ir[23]}},ir[23:8]};
|
| 459 |
|
|
state <= JSR1;
|
| 460 |
|
|
end
|
| 461 |
|
|
`JSR_INDX:
|
| 462 |
|
|
begin
|
| 463 |
|
|
radr <= isp - 32'd1;
|
| 464 |
|
|
wadr <= isp - 32'd1;
|
| 465 |
|
|
wdat <= pc + 32'd5;
|
| 466 |
|
|
cyc_o <= 1'b1;
|
| 467 |
|
|
stb_o <= 1'b1;
|
| 468 |
|
|
we_o <= 1'b1;
|
| 469 |
|
|
sel_o <= 4'hF;
|
| 470 |
|
|
adr_o <= {isp-32'd1,2'b00};
|
| 471 |
|
|
dat_o <= pc + 32'd5;
|
| 472 |
|
|
state <= JSR_INDX1;
|
| 473 |
|
|
end
|
| 474 |
|
|
// `JSR16:
|
| 475 |
|
|
// begin
|
| 476 |
|
|
// radr <= isp - 32'd1;
|
| 477 |
|
|
// wadr <= isp - 32'd1;
|
| 478 |
|
|
// wdat <= pc + 32'd3;
|
| 479 |
|
|
// cyc_o <= 1'b1;
|
| 480 |
|
|
// stb_o <= 1'b1;
|
| 481 |
|
|
// we_o <= 1'b1;
|
| 482 |
|
|
// sel_o <= 4'hF;
|
| 483 |
|
|
// adr_o <= {isp-32'd1,2'b00};
|
| 484 |
|
|
// dat_o <= pc + 32'd3;
|
| 485 |
|
|
// state <= JSR161;
|
| 486 |
|
|
// end
|
| 487 |
|
|
`RTS,`RTL:
|
| 488 |
|
|
begin
|
| 489 |
|
|
radr <= isp;
|
| 490 |
|
|
state <= RTS1;
|
| 491 |
|
|
end
|
| 492 |
|
|
`RTI: begin
|
| 493 |
|
|
radr <= isp;
|
| 494 |
|
|
state <= RTI1;
|
| 495 |
|
|
end
|
| 496 |
|
|
`BEQ,`BNE,`BPL,`BMI,`BCC,`BCS,`BVC,`BVS,`BRA:
|
| 497 |
|
|
begin
|
| 498 |
|
|
state <= IFETCH;
|
| 499 |
|
|
if (ir[15:8]==8'h00) begin
|
| 500 |
|
|
radr <= isp_dec;
|
| 501 |
|
|
wadr <= isp_dec;
|
| 502 |
|
|
wdat <= pc + 32'd2;
|
| 503 |
|
|
cyc_o <= 1'b1;
|
| 504 |
|
|
stb_o <= 1'b1;
|
| 505 |
|
|
we_o <= 1'b1;
|
| 506 |
|
|
sel_o <= 4'hF;
|
| 507 |
|
|
adr_o <= {isp_dec,2'b00};
|
| 508 |
|
|
dat_o <= pc + 32'd2;
|
| 509 |
|
|
vect <= {vbr[31:9],`SLP_VECTNO,2'b00};
|
| 510 |
|
|
state <= IRQ1;
|
| 511 |
|
|
end
|
| 512 |
|
|
else if (ir[15:8]==8'h1) begin
|
| 513 |
|
|
if (takb)
|
| 514 |
|
|
pc <= pc + {{16{ir[31]}},ir[31:16]};
|
| 515 |
|
|
else
|
| 516 |
|
|
pc <= pc + 32'd4;
|
| 517 |
|
|
end
|
| 518 |
|
|
else begin
|
| 519 |
|
|
if (takb)
|
| 520 |
|
|
pc <= pc + {{24{ir[15]}},ir[15:8]};
|
| 521 |
|
|
else
|
| 522 |
|
|
pc <= pc + 32'd2;
|
| 523 |
|
|
end
|
| 524 |
|
|
end
|
| 525 |
|
|
/* `BEQ_RR:
|
| 526 |
|
|
begin
|
| 527 |
|
|
state <= IFETCH;
|
| 528 |
|
|
if (ir[23:16]==8'h00) begin
|
| 529 |
|
|
radr <= isp_dec;
|
| 530 |
|
|
wadr <= isp_dec;
|
| 531 |
|
|
wdat <= pc + 32'd2;
|
| 532 |
|
|
cyc_o <= 1'b1;
|
| 533 |
|
|
stb_o <= 1'b1;
|
| 534 |
|
|
we_o <= 1'b1;
|
| 535 |
|
|
sel_o <= 4'hF;
|
| 536 |
|
|
adr_o <= {isp_dec,2'b00};
|
| 537 |
|
|
dat_o <= pc + 32'd2;
|
| 538 |
|
|
vect <= `SLP_VECT;
|
| 539 |
|
|
state <= IRQ1;
|
| 540 |
|
|
end
|
| 541 |
|
|
else if (ir[23:16]==8'h1) begin
|
| 542 |
|
|
if (rfoa==rfob)
|
| 543 |
|
|
pc <= pc + {{16{ir[39]}},ir[39:24]};
|
| 544 |
|
|
else
|
| 545 |
|
|
pc <= pc + 32'd5;
|
| 546 |
|
|
end
|
| 547 |
|
|
else begin
|
| 548 |
|
|
if (takb)
|
| 549 |
|
|
pc <= pc + {{24{ir[23]}},ir[23:16]};
|
| 550 |
|
|
else
|
| 551 |
|
|
pc <= pc + 32'd3;
|
| 552 |
|
|
end
|
| 553 |
|
|
end*/
|
| 554 |
|
|
`BRL:
|
| 555 |
|
|
begin
|
| 556 |
|
|
if (ir[23:8]==16'h0000) begin
|
| 557 |
|
|
radr <= isp_dec;
|
| 558 |
|
|
wadr <= isp_dec;
|
| 559 |
|
|
wdat <= pc + 32'd3;
|
| 560 |
|
|
cyc_o <= 1'b1;
|
| 561 |
|
|
stb_o <= 1'b1;
|
| 562 |
|
|
we_o <= 1'b1;
|
| 563 |
|
|
sel_o <= 4'hF;
|
| 564 |
|
|
adr_o <= {isp_dec,2'b00};
|
| 565 |
|
|
dat_o <= pc + 32'd3;
|
| 566 |
|
|
vect <= {vbr[31:9],`SLP_VECTNO,2'b00};
|
| 567 |
|
|
state <= IRQ1;
|
| 568 |
|
|
end
|
| 569 |
|
|
else begin
|
| 570 |
|
|
pc <= pc + {{16{ir[23]}},ir[23:8]};
|
| 571 |
|
|
state <= IFETCH;
|
| 572 |
|
|
end
|
| 573 |
|
|
end
|
| 574 |
|
|
`PHP:
|
| 575 |
|
|
begin
|
| 576 |
|
|
cyc_o <= 1'b1;
|
| 577 |
|
|
stb_o <= 1'b1;
|
| 578 |
|
|
sel_o <= 4'hF;
|
| 579 |
|
|
we_o <= 1'b1;
|
| 580 |
|
|
radr <= isp_dec;
|
| 581 |
|
|
wadr <= isp_dec;
|
| 582 |
|
|
wdat <= sr;
|
| 583 |
|
|
adr_o <= {isp_dec,2'b00};
|
| 584 |
|
|
dat_o <= sr;
|
| 585 |
|
|
isp <= isp_dec;
|
| 586 |
|
|
state <= PHP1;
|
| 587 |
|
|
end
|
| 588 |
|
|
`PHA:
|
| 589 |
|
|
begin
|
| 590 |
|
|
cyc_o <= 1'b1;
|
| 591 |
|
|
stb_o <= 1'b1;
|
| 592 |
|
|
sel_o <= 4'hF;
|
| 593 |
|
|
we_o <= 1'b1;
|
| 594 |
|
|
radr <= isp_dec;
|
| 595 |
|
|
wadr <= isp_dec;
|
| 596 |
|
|
wdat <= acc;
|
| 597 |
|
|
adr_o <= {isp_dec,2'b00};
|
| 598 |
|
|
dat_o <= acc;
|
| 599 |
|
|
isp <= isp_dec;
|
| 600 |
|
|
state <= PHP1;
|
| 601 |
|
|
end
|
| 602 |
|
|
`PHX:
|
| 603 |
|
|
begin
|
| 604 |
|
|
cyc_o <= 1'b1;
|
| 605 |
|
|
stb_o <= 1'b1;
|
| 606 |
|
|
sel_o <= 4'hF;
|
| 607 |
|
|
we_o <= 1'b1;
|
| 608 |
|
|
radr <= isp_dec;
|
| 609 |
|
|
wadr <= isp_dec;
|
| 610 |
|
|
wdat <= x;
|
| 611 |
|
|
adr_o <= {isp_dec,2'b00};
|
| 612 |
|
|
dat_o <= x;
|
| 613 |
|
|
isp <= isp_dec;
|
| 614 |
|
|
state <= PHP1;
|
| 615 |
|
|
end
|
| 616 |
|
|
`PHY:
|
| 617 |
|
|
begin
|
| 618 |
|
|
cyc_o <= 1'b1;
|
| 619 |
|
|
stb_o <= 1'b1;
|
| 620 |
|
|
sel_o <= 4'hF;
|
| 621 |
|
|
we_o <= 1'b1;
|
| 622 |
|
|
radr <= isp_dec;
|
| 623 |
|
|
wadr <= isp_dec;
|
| 624 |
|
|
wdat <= y;
|
| 625 |
|
|
adr_o <= {isp_dec,2'b00};
|
| 626 |
|
|
dat_o <= y;
|
| 627 |
|
|
isp <= isp_dec;
|
| 628 |
|
|
state <= PHP1;
|
| 629 |
|
|
end
|
| 630 |
|
|
`PUSH:
|
| 631 |
|
|
begin
|
| 632 |
|
|
cyc_o <= 1'b1;
|
| 633 |
|
|
stb_o <= 1'b1;
|
| 634 |
|
|
sel_o <= 4'hF;
|
| 635 |
|
|
we_o <= 1'b1;
|
| 636 |
|
|
radr <= isp_dec;
|
| 637 |
|
|
wadr <= isp_dec;
|
| 638 |
|
|
wdat <= rfoa;
|
| 639 |
|
|
adr_o <= {isp_dec,2'b00};
|
| 640 |
|
|
dat_o <= rfoa;
|
| 641 |
|
|
state <= PHP1;
|
| 642 |
|
|
isp <= isp_dec;
|
| 643 |
|
|
pc <= pc + 32'd1;
|
| 644 |
|
|
end
|
| 645 |
|
|
`PLP:
|
| 646 |
|
|
begin
|
| 647 |
|
|
radr <= isp;
|
| 648 |
|
|
state <= PLP1;
|
| 649 |
|
|
pc <= pc + 32'd1;
|
| 650 |
|
|
end
|
| 651 |
|
|
`PLA,`PLX,`PLY:
|
| 652 |
|
|
begin
|
| 653 |
|
|
radr <= isp;
|
| 654 |
|
|
isp <= isp_inc;
|
| 655 |
|
|
state <= PLA1;
|
| 656 |
|
|
pc <= pc + 32'd1;
|
| 657 |
|
|
end
|
| 658 |
|
|
`POP:
|
| 659 |
|
|
begin
|
| 660 |
|
|
Rt <= ir[15:12];
|
| 661 |
|
|
radr <= isp;
|
| 662 |
|
|
isp <= isp_inc;
|
| 663 |
|
|
state <= PLA1;
|
| 664 |
|
|
pc <= pc + 32'd2;
|
| 665 |
|
|
end
|
| 666 |
|
|
default: // unimplemented opcode
|
| 667 |
|
|
pc <= pc + 32'd1;
|
| 668 |
|
|
endcase
|
| 669 |
|
|
end
|
