/* This file is part of the dynarmic project.
 * Copyright (c) 2016 MerryMage
 * SPDX-License-Identifier: 0BSD
 */

#include <dynarmic/A32/config.h>

#include "common/assert.h"
#include "frontend/A32/decoder/arm.h"
#include "frontend/A32/decoder/asimd.h"
#include "frontend/A32/decoder/vfp.h"
#include "frontend/A32/location_descriptor.h"
#include "frontend/A32/translate/conditional_state.h"
#include "frontend/A32/translate/impl/translate_arm.h"
#include "frontend/A32/translate/translate.h"
#include "frontend/A32/types.h"
#include "frontend/ir/basic_block.h"

namespace Dynarmic::A32 {

IR::Block TranslateArm(LocationDescriptor descriptor, MemoryReadCodeFuncType memory_read_code, const TranslationOptions& options) {
    const bool single_step = descriptor.SingleStepping();

    IR::Block block{descriptor};
    ArmTranslatorVisitor visitor{block, descriptor, options};

    bool should_continue = true;
    do {
        const u32 arm_pc = visitor.ir.current_location.PC();
        const u32 arm_instruction = memory_read_code(arm_pc);

        if (const auto vfp_decoder = DecodeVFP<ArmTranslatorVisitor>(arm_instruction)) {
            should_continue = vfp_decoder->get().call(visitor, arm_instruction);
        } else if (const auto asimd_decoder = DecodeASIMD<ArmTranslatorVisitor>(arm_instruction)) {
            should_continue = asimd_decoder->get().call(visitor, arm_instruction);
        } else if (const auto decoder = DecodeArm<ArmTranslatorVisitor>(arm_instruction)) {
            should_continue = decoder->get().call(visitor, arm_instruction);
        } else {
            should_continue = visitor.arm_UDF();
        }

        if (visitor.cond_state == ConditionalState::Break) {
            break;
        }

        visitor.ir.current_location = visitor.ir.current_location.AdvancePC(4);
        block.CycleCount()++;
    } while (should_continue && CondCanContinue(visitor.cond_state, visitor.ir) && !single_step);

    if (visitor.cond_state == ConditionalState::Translating || visitor.cond_state == ConditionalState::Trailing || single_step) {
        if (should_continue) {
            if (single_step) {
                visitor.ir.SetTerm(IR::Term::LinkBlock{visitor.ir.current_location});
            } else {
                visitor.ir.SetTerm(IR::Term::LinkBlockFast{visitor.ir.current_location});
            }
        }
    }

    ASSERT_MSG(block.HasTerminal(), "Terminal has not been set");

    block.SetEndLocation(visitor.ir.current_location);

    return block;
}

bool TranslateSingleArmInstruction(IR::Block& block, LocationDescriptor descriptor, u32 arm_instruction) {
    ArmTranslatorVisitor visitor{block, descriptor, {}};

    // TODO: Proper cond handling

    bool should_continue = true;
    if (const auto vfp_decoder = DecodeVFP<ArmTranslatorVisitor>(arm_instruction)) {
        should_continue = vfp_decoder->get().call(visitor, arm_instruction);
    } else if (const auto asimd_decoder = DecodeASIMD<ArmTranslatorVisitor>(arm_instruction)) {
        should_continue = asimd_decoder->get().call(visitor, arm_instruction);
    } else if (const auto decoder = DecodeArm<ArmTranslatorVisitor>(arm_instruction)) {
        should_continue = decoder->get().call(visitor, arm_instruction);
    } else {
        should_continue = visitor.arm_UDF();
    }

    // TODO: Feedback resulting cond status to caller somehow.

    visitor.ir.current_location = visitor.ir.current_location.AdvancePC(4);
    block.CycleCount()++;

    block.SetEndLocation(visitor.ir.current_location);

    return should_continue;
}

bool ArmTranslatorVisitor::ConditionPassed(Cond cond) {
    return IsConditionPassed(cond, cond_state, ir, 4);
}

bool ArmTranslatorVisitor::InterpretThisInstruction() {
    ir.SetTerm(IR::Term::Interpret(ir.current_location));
    return false;
}

bool ArmTranslatorVisitor::UnpredictableInstruction() {
    ir.ExceptionRaised(Exception::UnpredictableInstruction);
    ir.SetTerm(IR::Term::CheckHalt{IR::Term::ReturnToDispatch{}});
    return false;
}

bool ArmTranslatorVisitor::UndefinedInstruction() {
    ir.ExceptionRaised(Exception::UndefinedInstruction);
    ir.SetTerm(IR::Term::CheckHalt{IR::Term::ReturnToDispatch{}});
    return false;
}

bool ArmTranslatorVisitor::DecodeError() {
    ir.ExceptionRaised(Exception::DecodeError);
    ir.SetTerm(IR::Term::CheckHalt{IR::Term::ReturnToDispatch{}});
    return false;
}

bool ArmTranslatorVisitor::RaiseException(Exception exception) {
    ir.BranchWritePC(ir.Imm32(ir.current_location.PC() + 4));
    ir.ExceptionRaised(exception);
    ir.SetTerm(IR::Term::CheckHalt{IR::Term::ReturnToDispatch{}});
    return false;
}

IR::UAny ArmTranslatorVisitor::I(size_t bitsize, u64 value) {
    switch (bitsize) {
    case 8:
        return ir.Imm8(static_cast<u8>(value));
    case 16:
        return ir.Imm16(static_cast<u16>(value));
    case 32:
        return ir.Imm32(static_cast<u32>(value));
    case 64:
        return ir.Imm64(value);
    default:
        ASSERT_FALSE("Imm - get: Invalid bitsize");
    }
}

IR::ResultAndCarry<IR::U32> ArmTranslatorVisitor::EmitImmShift(IR::U32 value, ShiftType type, Imm<5> imm5, IR::U1 carry_in) {
    u8 imm5_value = imm5.ZeroExtend<u8>();
    switch (type) {
    case ShiftType::LSL:
        return ir.LogicalShiftLeft(value, ir.Imm8(imm5_value), carry_in);
    case ShiftType::LSR:
        imm5_value = imm5_value ? imm5_value : 32;
        return ir.LogicalShiftRight(value, ir.Imm8(imm5_value), carry_in);
    case ShiftType::ASR:
        imm5_value = imm5_value ? imm5_value : 32;
        return ir.ArithmeticShiftRight(value, ir.Imm8(imm5_value), carry_in);
    case ShiftType::ROR:
        if (imm5_value) {
            return ir.RotateRight(value, ir.Imm8(imm5_value), carry_in);
        } else {
            return ir.RotateRightExtended(value, carry_in);
        }
    }
    UNREACHABLE();
}

IR::ResultAndCarry<IR::U32> ArmTranslatorVisitor::EmitRegShift(IR::U32 value, ShiftType type, IR::U8 amount, IR::U1 carry_in) {
    switch (type) {
    case ShiftType::LSL:
        return ir.LogicalShiftLeft(value, amount, carry_in);
    case ShiftType::LSR:
        return ir.LogicalShiftRight(value, amount, carry_in);
    case ShiftType::ASR:
        return ir.ArithmeticShiftRight(value, amount, carry_in);
    case ShiftType::ROR:
        return ir.RotateRight(value, amount, carry_in);
    }
    UNREACHABLE();
}

} // namespace Dynarmic::A32