// Copyright 2018 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.

#include "common/assert.h"
#include "common/common_types.h"
#include "video_core/engines/shader_bytecode.h"
#include "video_core/shader/shader_ir.h"

namespace VideoCommon::Shader {

using Tegra::Shader::Instruction;
using Tegra::Shader::OpCode;
using Tegra::Shader::Register;

u32 ShaderIR::DecodeConversion(BasicBlock& bb, u32 pc) {
    const Instruction instr = {program_code[pc]};
    const auto opcode = OpCode::Decode(instr);

    switch (opcode->get().GetId()) {
    case OpCode::Id::I2F_R:
    case OpCode::Id::I2F_C: {
        UNIMPLEMENTED_IF(instr.conversion.dest_size != Register::Size::Word);
        UNIMPLEMENTED_IF(instr.conversion.selector);
        UNIMPLEMENTED_IF_MSG(instr.generates_cc,
                             "Condition codes generation in I2F is not implemented");

        Node value = [&]() {
            if (instr.is_b_gpr) {
                return GetRegister(instr.gpr20);
            } else {
                return GetConstBuffer(instr.cbuf34.index, instr.cbuf34.offset);
            }
        }();
        const bool input_signed = instr.conversion.is_input_signed;
        value = ConvertIntegerSize(value, instr.conversion.src_size, input_signed);
        value = GetOperandAbsNegInteger(value, instr.conversion.abs_a, false, input_signed);
        value = SignedOperation(OperationCode::FCastInteger, input_signed, PRECISE, value);
        value = GetOperandAbsNegFloat(value, false, instr.conversion.negate_a);

        SetRegister(bb, instr.gpr0, value);
        break;
    }
    case OpCode::Id::F2F_R: {
        UNIMPLEMENTED_IF(instr.conversion.dest_size != Register::Size::Word);
        UNIMPLEMENTED_IF(instr.conversion.src_size != Register::Size::Word);
        UNIMPLEMENTED_IF_MSG(instr.generates_cc,
                             "Condition codes generation in F2F is not implemented");

        Node value = GetRegister(instr.gpr20);
        value = GetOperandAbsNegFloat(value, instr.conversion.abs_a, instr.conversion.negate_a);

        value = [&]() {
            switch (instr.conversion.f2f.rounding) {
            case Tegra::Shader::F2fRoundingOp::None:
                return value;
            case Tegra::Shader::F2fRoundingOp::Round:
                return Operation(OperationCode::FRoundEven, PRECISE, value);
            case Tegra::Shader::F2fRoundingOp::Floor:
                return Operation(OperationCode::FFloor, PRECISE, value);
            case Tegra::Shader::F2fRoundingOp::Ceil:
                return Operation(OperationCode::FCeil, PRECISE, value);
            case Tegra::Shader::F2fRoundingOp::Trunc:
                return Operation(OperationCode::FTrunc, PRECISE, value);
            default:
                UNIMPLEMENTED_MSG("Unimplemented F2F rounding mode {}",
                                  static_cast<u32>(instr.conversion.f2f.rounding.Value()));
                break;
            }
        }();
        value = GetSaturatedFloat(value, instr.alu.saturate_d);

        SetRegister(bb, instr.gpr0, value);
        break;
    }
    case OpCode::Id::F2I_R:
    case OpCode::Id::F2I_C: {
        UNIMPLEMENTED_IF(instr.conversion.src_size != Register::Size::Word);
        UNIMPLEMENTED_IF_MSG(instr.generates_cc,
                             "Condition codes generation in F2I is not implemented");
        Node value = [&]() {
            if (instr.is_b_gpr) {
                return GetRegister(instr.gpr20);
            } else {
                return GetConstBuffer(instr.cbuf34.index, instr.cbuf34.offset);
            }
        }();

        value = GetOperandAbsNegFloat(value, instr.conversion.abs_a, instr.conversion.negate_a);

        value = [&]() {
            switch (instr.conversion.f2i.rounding) {
            case Tegra::Shader::F2iRoundingOp::None:
                return value;
            case Tegra::Shader::F2iRoundingOp::Floor:
                return Operation(OperationCode::FFloor, PRECISE, value);
            case Tegra::Shader::F2iRoundingOp::Ceil:
                return Operation(OperationCode::FCeil, PRECISE, value);
            case Tegra::Shader::F2iRoundingOp::Trunc:
                return Operation(OperationCode::FTrunc, PRECISE, value);
            default:
                UNIMPLEMENTED_MSG("Unimplemented F2I rounding mode {}",
                                  static_cast<u32>(instr.conversion.f2i.rounding.Value()));
            }
        }();
        const bool is_signed = instr.conversion.is_output_signed;
        value = SignedOperation(OperationCode::ICastFloat, is_signed, PRECISE, value);
        value = ConvertIntegerSize(value, instr.conversion.dest_size, is_signed);

        SetRegister(bb, instr.gpr0, value);
        break;
    }
    default:
        UNIMPLEMENTED_MSG("Unhandled conversion instruction: {}", opcode->get().GetName());
    }

    return pc;
}

} // namespace VideoCommon::Shader