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/>.

// aam

void EmulatorPimpl::aamd4()

{

    auto divisor = fetch_byte();

    if (divisor == 0) {

        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;

    }

    auto al = registers->get(AL);

    auto quotient = al / divisor;

    auto remainder = al % divisor;

    registers->set(AH, quotient);

    registers->set(AL, remainder);

    uint16_t flags = registers->get_flags();

    flags &= ~(PF | SF | ZF);

    if (!(registers->get(AX) & 0xffff))

        flags |= ZF;

    if (!__builtin_parity(registers->get(AL) & 0xff))

        flags |= PF;

    if (registers->get(AX) & 0x8000)

        flags |= SF;

    registers->set_flags(flags, SF | ZF | PF);

}