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/>.

// div r/m, 8-bit

void EmulatorPimpl::divf6()

{

    auto divisor = read_data<uint8_t>();

    auto dividend = registers->get(AX);

    if (divisor == 0 || ((dividend / divisor) & 0xff00)) {

        auto flags = registers->get_flags();

        push_word(flags);

        push_word(registers->get(CS));

        push_word(registers->get(IP));

        flags &= ~(IF | TF);

        registers->set_flags(flags, IF | TF);

        auto new_cs = mem->read<uint16_t>(VEC_DIVIDE_ERROR + 2);

        auto new_ip = mem->read<uint16_t>(VEC_DIVIDE_ERROR + 0);

        registers->set(CS, new_cs);

        registers->set(IP, new_ip);

        jump_taken = true;

        return;

    }

    uint8_t quotient = dividend / divisor;

    uint8_t remainder = dividend % divisor;

    registers->set(AH, remainder);

    registers->set(AL, quotient);

}

// div r/m, 16-bit

void EmulatorPimpl::divf7()

{

    auto divisor = read_data<uint16_t>();

    uint32_t dividend =

        (static_cast<uint32_t>(registers->get(DX)) << 16) | registers->get(AX);

    if (divisor == 0 || ((dividend / divisor) & 0xffff0000)) {

        auto flags = registers->get_flags();

        push_word(flags);

        push_word(registers->get(CS));

        push_word(registers->get(IP));

        flags &= ~(IF | TF);

        registers->set_flags(flags, IF | TF);

        auto new_cs = mem->read<uint16_t>(VEC_DIVIDE_ERROR + 2);

        auto new_ip = mem->read<uint16_t>(VEC_DIVIDE_ERROR + 0);

        registers->set(CS, new_cs);

        registers->set(IP, new_ip);

        jump_taken = true;

        return;

    }

    uint16_t quotient = dividend / divisor;

    uint16_t remainder = dividend % divisor;

    registers->set(DX, remainder);

    registers->set(AX, quotient);

}

// idiv r/m, 8-bit

void EmulatorPimpl::idivf6()

{

    int8_t divisor = static_cast<int8_t>(read_data<uint8_t>());

    int16_t dividend = static_cast<int16_t>(registers->get(AX));

    if (divisor == 0 || (dividend / divisor < -128) ||

        (dividend / divisor > 127)) {

        auto flags = registers->get_flags();

        push_word(flags);

        push_word(registers->get(CS));

        push_word(registers->get(IP));

        flags &= ~(IF | TF);

        registers->set_flags(flags, IF | TF);

        auto new_cs = mem->read<uint16_t>(VEC_DIVIDE_ERROR + 2);

        auto new_ip = mem->read<uint16_t>(VEC_DIVIDE_ERROR + 0);

        registers->set(CS, new_cs);

        registers->set(IP, new_ip);

        jump_taken = true;

        return;

    }

    int8_t quotient = dividend / divisor;

    int8_t remainder = dividend % divisor;

    registers->set(AH, remainder);

    registers->set(AL, quotient);

}

// div r/m, 16-bit

void EmulatorPimpl::idivf7()

{

    auto divisor = static_cast<int16_t>(read_data<uint16_t>());

    int32_t dividend =

        (static_cast<uint32_t>(registers->get(DX)) << 16) | registers->get(AX);

    if (divisor == 0 || (dividend / divisor < -32768) ||

        (dividend / divisor) > 32767) {

        auto flags = registers->get_flags();

        push_word(flags);

        push_word(registers->get(CS));

        push_word(registers->get(IP));

        flags &= ~(IF | TF);

        registers->set_flags(flags, IF | TF);

        auto new_cs = mem->read<uint16_t>(VEC_DIVIDE_ERROR + 2);

        auto new_ip = mem->read<uint16_t>(VEC_DIVIDE_ERROR + 0);

        registers->set(CS, new_cs);

        registers->set(IP, new_ip);

        jump_taken = true;

        return;

    }

    int16_t quotient = dividend / divisor;

    int16_t remainder = dividend % divisor;

    registers->set(DX, remainder);

    registers->set(AX, quotient);

}