Subversion Repositories s80186

// Copyright Jamie Iles, 2017

//

// This file is part of s80x86.

//

// s80x86 is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

//

// s80x86 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 General Public License for more details.

//

// You should have received a copy of the GNU General Public License

// along with s80x86.  If not, see .

module JumpTest(input logic [7:0] opcode,

                // verilator lint_off UNUSED

                input logic [15:0] flags,

                // verilator lint_on UNUSED

                output logic taken);

always_comb begin

    taken = 1'b0;

    unique casez(opcode)

    8'b01100010: taken = flags[CF_IDX]; // BOUND

    8'b01110000: taken = flags[OF_IDX]; // JO

    8'b01110001: taken = ~flags[OF_IDX]; // JNO

    8'b01110010: taken = flags[CF_IDX]; // JB

    8'b01110011: taken = ~flags[CF_IDX]; // JNB

    8'b01110100: taken = flags[ZF_IDX]; // JE

    8'b01110101: taken = ~flags[ZF_IDX]; // JNE

    8'b01110110: taken = flags[CF_IDX] | flags[ZF_IDX]; // JBE

    8'b01110111: taken = ~(flags[CF_IDX] | flags[ZF_IDX]); // JNBE

    8'b01111000: taken = flags[SF_IDX]; // JS

    8'b01111001: taken = ~flags[SF_IDX]; // JNS

    8'b01111010: taken = flags[PF_IDX]; // JP

    8'b01111011: taken = ~flags[PF_IDX]; // JNP

    8'b01111100: taken = flags[OF_IDX] ^ flags[SF_IDX]; // JL

    8'b01111101: taken = ~(flags[SF_IDX] ^ flags[OF_IDX]); // JNL

    8'b01111110: taken = (flags[OF_IDX] ^ flags[SF_IDX]) | flags[ZF_IDX]; // JLE

    8'b01111111: taken = ~((flags[SF_IDX] ^ flags[OF_IDX]) | flags[ZF_IDX]); // JNLE

    8'b11001110: taken = flags[OF_IDX]; // INTO

    default: taken = 1'b0;

    endcase

end

endmodule