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 <http://www.gnu.org/licenses/>.

#include <gtest/gtest.h>

#include <VSegmentOverride.h>

#include "VerilogTestbench.h"

class SegmentOverrideTestFixture : public VerilogTestbench<VSegmentOverride>,

                                   public ::testing::Test

{

public:

    void add_override(uint8_t segnum)

    {

        after_n_cycles(0, [segnum, this] {

            this->dut.microcode_sr_rd_sel = segnum;

            this->dut.segment_override = 1;

            after_n_cycles(1, [&] { this->dut.segment_override = 0; });

        });

    }

    void next_instruction()

    {

        after_n_cycles(0, [&] {

            this->dut.next_instruction = 1;

            after_n_cycles(1, [&] { this->dut.next_instruction = 0; });

        });

    }

};

// How to select a segment:

//

// - If the microcode forces a segment, use it.

// - If not, and there is a segment override, use that.

// - If not forced and not overriden, then use the default that the microcode

// specifies, unless BP is used as a base register, in which case use SS.

TEST_F(SegmentOverrideTestFixture, UseSSIfBPIsBase)

{

    this->dut.bp_is_base = 1;

    this->dut.microcode_sr_rd_sel = 3;

    cycle();

    ASSERT_EQ(this->dut.sr_rd_sel, 2);

}

TEST_F(SegmentOverrideTestFixture, UseMicrocodeIfNotBPIsBase)

{

    this->dut.bp_is_base = 0;

    this->dut.microcode_sr_rd_sel = 3;

    cycle();

    ASSERT_EQ(this->dut.sr_rd_sel, 3);

}

TEST_F(SegmentOverrideTestFixture, Override)

{

    add_override(0);

    this->dut.bp_is_base = 0;

    this->dut.microcode_sr_rd_sel = 3;

    cycle();

    ASSERT_EQ(this->dut.sr_rd_sel, 0);

}

TEST_F(SegmentOverrideTestFixture, NextInstructionClearsOverride)

{

    add_override(0);

    this->dut.microcode_sr_rd_sel = 3;

    cycle();

    this->dut.microcode_sr_rd_sel = 2;

    next_instruction();

    cycle();

    ASSERT_EQ(this->dut.sr_rd_sel, 2);

}

TEST_F(SegmentOverrideTestFixture, ForceWins)

{

    add_override(0);

    cycle();

    this->dut.force_segment = 1;

    this->dut.bp_is_base = 1;

    this->dut.microcode_sr_rd_sel = 1;

    cycle();

    this->dut.microcode_sr_rd_sel = 1;

    this->dut.eval();

    ASSERT_EQ(this->dut.sr_rd_sel, 1);

}