#include <broadway/utils.hpp>
#include "ircolib/log.hpp"
#include <mem.hpp>

namespace weee::core {
void broadway::add(ircolib::u32 instr) { gpr[utils::RD(instr)] = gpr[utils::RA(instr)] + gpr[utils::RB(instr)]; }

void broadway::addi(ircolib::u32 instr) {
    if (utils::RA(instr) == 0) { // lis
        gpr[utils::RD(instr)] = ircolib::s32(utils::SIMM(instr));
        return;
    }

    gpr[utils::RD(instr)] = gpr[utils::RA(instr)] + (ircolib::s32(utils::SIMM(instr)));
}

void broadway::addis(ircolib::u32 instr) {
    if (utils::RA(instr) == 0) { // lis
        gpr[utils::RD(instr)] = ircolib::s32(utils::SIMM(instr)) << 16;
        return;
    }

    gpr[utils::RD(instr)] = gpr[utils::RA(instr)] + (ircolib::s32(utils::SIMM(instr)) << 16);
}

void broadway::ori(ircolib::u32 instr) { gpr[utils::RA(instr)] = gpr[utils::RS(instr)] | utils::UIMM(instr); }

void broadway::bx(ircolib::u32 instr) {
    const bool link = instr & 1;
    const bool absolute = instr & 2;

    ircolib::s32 li = (ircolib::s32(instr << 6) >> 6) & 0xFFFFFFFC;
    if (!absolute)
        li += pc - 4;

    if (link)
        lr = pc;

    pc = li;
}

void broadway::bcx(ircolib::u32 instr) {
    const bool link = instr & 1;
    const bool absolute = instr & 2;

    ircolib::s32 bd = (ircolib::s32(instr << 16) >> 16) & 0xFFFFFFFC;
    if (!absolute)
        bd += pc - 4;

    if (!ircolib::is_bit_set<ircolib::u32, 25>(instr))
        ircolib::panic("broadway::bcx unimplemented variants with bit 25 == 0");

    if (ircolib::is_bit_set<ircolib::u32, 23>(instr)) { // always
        if (link)
            lr = pc;

        pc = bd;
        return;
    }

    if (ircolib::is_bit_set<ircolib::u32, 22>(instr)) { // --ctr == 0
        if (--ctr != 0)
            return;

        if (link)
            lr = pc;

        pc = bd;
        return;
    }

    // --ctr != 0
    if (--ctr == 0)
        return;

    if (link)
        lr = pc;

    pc = bd;
}

void broadway::mfspr(ircolib::u32 instr) {
    const size_t spr_field = (instr >> 11) & 0x3FF;
    switch (spr_field) {
    case 0b0000100000:
        gpr[utils::RD(instr)] = xer.raw;
        break;
    case 0b0100000000:
        gpr[utils::RD(instr)] = lr;
        break;
    case 0b0100100000:
        gpr[utils::RD(instr)] = ctr;
        break;
    default:
        ircolib::panic("broadway::mfspr with unimplemented spr field of value 0x{:04X}", spr_field);
    }
}

void broadway::mtspr(ircolib::u32 instr) {
    const size_t spr_field = (instr >> 11) & 0x3FF;
    switch (spr_field) {
    case 0b0000100000:
        xer.raw = gpr[utils::RS(instr)];
        break;
    case 0b0100000000:
        lr = gpr[utils::RS(instr)];
        break;
    case 0b0100100000:
        ctr = gpr[utils::RS(instr)];
        break;
    default:
        ircolib::panic("broadway::mtspr with unimplemented spr field of value 0x{:04X}", spr_field);
    }
}

void broadway::stwu(ircolib::u32 instr, mem &mem) {
    if (utils::RA(instr) == 0)
        ircolib::panic("broadway::stwu with ra == 0");

    const ircolib::u32 EA = ircolib::s32(gpr[utils::RA(instr)]) + utils::SIMM(instr);
    mem.write32(EA, gpr[utils::RS(instr)]);
    gpr[utils::RA(instr)] = EA;
}

void broadway::stw(ircolib::u32 instr, mem &mem) {
    ircolib::s32 b = gpr[utils::RA(instr)];
    if (utils::RA(instr) == 0)
        b = 0;

    const ircolib::u32 EA = b + utils::SIMM(instr);
    mem.write32(EA, gpr[utils::RS(instr)]);
}

void broadway::sth(ircolib::u32 instr, mem &mem) {
    ircolib::u32 b = gpr[utils::RA(instr)];
    if (utils::RA(instr) == 0)
        b = 0;

    const ircolib::s32 d = utils::SIMM(instr);
    const ircolib::u32 EA = b + d;

    mem.write16(EA, ircolib::u16(gpr[utils::RS(instr)]));
}

void broadway::lwz(ircolib::u32 instr, mem &mem) {
    ircolib::u32 b = gpr[utils::RA(instr)];
    if (utils::RA(instr) == 0)
        b = 0;

    ircolib::u32 ea = ircolib::s32(b) + utils::SIMM(instr);
    gpr[utils::RD(instr)] = mem.read32(ea);
}

void broadway::bclrx(ircolib::u32 instr) {
    const bool link = instr & 1;

    ircolib::s32 bd = lr & 0xFFFFFFFC;

    if (!ircolib::is_bit_set<ircolib::u32, 25>(instr)) {
        if (!ircolib::is_bit_set<ircolib::u32, 24>(instr))
            ircolib::panic("broadway::bclrx unimplemented variants with bit 24 == 0");

        if (!ircolib::is_bit_set<ircolib::u32, 23>(instr))
            ircolib::panic("broadway::bclrx unimplemented variants with bit 23 == 0");

        const ircolib::u8 bi = (instr >> 16) & 0x1f;

        if (ircolib::is_bit_set(cr, 32 - bi)) {
            if (link)
                lr = pc;

            pc = bd;
        }

        return;
    }

    if (ircolib::is_bit_set<ircolib::u32, 23>(instr)) { // always
        if (link)
            lr = pc;

        pc = bd;
        return;
    }

    if (ircolib::is_bit_set<ircolib::u32, 22>(instr)) { // --ctr == 0
        if (--ctr != 0)
            return;

        if (link)
            lr = pc;

        pc = bd;
        return;
    }

    // --ctr != 0
    if (--ctr == 0)
        return;

    if (link)
        lr = pc;

    pc = bd;
}

void broadway::cmpi(ircolib::u32 instr) {
    const ircolib::s32 a = gpr[utils::RA(instr)];
    const ircolib::s32 simm = utils::SIMM(instr);
    ircolib::u8 c;
    if (a < simm)
        c = 0b001;
    else if (a > simm)
        c = 0b010;
    else
        c = 0b100;

    const ircolib::u32 result = ((xer.so << 3) | c) << (28 - 4 * utils::crfD(instr));
    cr &= ~(0xffff << (28 - 4 * utils::crfD(instr)));
    cr |= result;
}

void broadway::rlwinm(ircolib::u32 instr) {
    const ircolib::u8 sh = (instr >> 11) & 0x1f;
    ircolib::u32 r = std::rotl(gpr[utils::RS(instr)], sh);
    const ircolib::u8 mb = (instr >> 6) & 0x1f;
    const ircolib::u8 me = (instr >> 1) & 0x1f;

    r &= ~((0xFFFF'FFFF >> mb) << me);
    gpr[utils::RA(instr)] = r;
}

void broadway::lwzu(ircolib::u32 instr, mem &mem) {
    if (utils::RA(instr) == 0 || utils::RA(instr) == utils::RD(instr))
        ircolib::panic("broadway::lwzu with ra == 0");

    const ircolib::u32 EA = ircolib::s32(gpr[utils::RA(instr)]) + utils::SIMM(instr);
    gpr[utils::RD(instr)] = mem.read32(EA);
    gpr[utils::RA(instr)] = EA;
}
} // namespace weee::core