/*******************************************************************************
 * Copyright (C) 2021 MINRES Technologies GmbH
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 *******************************************************************************/
<%
def nativeTypeSize(int size){
    if(size<=8) return 8; else if(size<=16) return 16; else if(size<=32) return 32; else return 64;
}
%>
#include <iss/debugger/gdb_session.h>
#include <iss/debugger/server.h>
#include <iss/arch/${coreDef.name.toLowerCase()}.h>
#include <iss/arch/riscv_hart_m_p.h>
#include <iss/iss.h>
#include <iss/interp/vm_base.h>
#include <util/logging.h>
#include <sstream>
#include <boost/coroutine2/all.hpp>
#include <functional>

#ifndef FMT_HEADER_ONLY
#define FMT_HEADER_ONLY
#endif
#include <fmt/format.h>

#include <array>
#include <iss/debugger/riscv_target_adapter.h>

namespace iss {
namespace interp {
namespace ${coreDef.name.toLowerCase()} {
using namespace iss::arch;
using namespace iss::debugger;
using namespace std::placeholders;

template <typename ARCH> class vm_impl : public iss::interp::vm_base<ARCH> {
public:
    using traits = arch::traits<ARCH>;
    using super       = typename iss::interp::vm_base<ARCH>;
    using virt_addr_t = typename super::virt_addr_t;
    using phys_addr_t = typename super::phys_addr_t;
    using code_word_t = typename super::code_word_t;
    using addr_t      = typename super::addr_t;
    using reg_t       = typename traits::reg_t;
    using mem_type_e  = typename traits::mem_type_e;
    using opcode_e    = typename traits::opcode_e;
    
    vm_impl();

    vm_impl(ARCH &core, unsigned core_id = 0, unsigned cluster_id = 0);

    void enableDebug(bool enable) { super::sync_exec = super::ALL_SYNC; }

    target_adapter_if *accquire_target_adapter(server_if *srv) override {
        debugger_if::dbg_enabled = true;
        if (super::tgt_adapter == nullptr)
            super::tgt_adapter = new riscv_target_adapter<ARCH>(srv, this->get_arch());
        return super::tgt_adapter;
    }

protected:
    using this_class = vm_impl<ARCH>;
    using compile_ret_t = virt_addr_t;
    using compile_func = compile_ret_t (this_class::*)(virt_addr_t &pc, code_word_t instr);

    inline const char *name(size_t index){return index<traits::reg_aliases.size()?traits::reg_aliases[index]:"illegal";}

    typename arch::traits<ARCH>::opcode_e decode_inst_id(code_word_t instr);
    virt_addr_t execute_inst(finish_cond_e cond, virt_addr_t start, uint64_t icount_limit) override;

    // some compile time constants
    // enum { MASK16 = 0b1111110001100011, MASK32 = 0b11111111111100000111000001111111 };
    enum { MASK16 = 0b1111111111111111, MASK32 = 0b11111111111100000111000001111111 };
    enum { EXTR_MASK16 = MASK16 >> 2, EXTR_MASK32 = MASK32 >> 2 };
    enum {
        LUT_SIZE = 1 << util::bit_count(static_cast<uint32_t>(EXTR_MASK32)),
        LUT_SIZE_C = 1 << util::bit_count(static_cast<uint32_t>(EXTR_MASK16))
    };

    std::array<compile_func, LUT_SIZE> lut;

    std::array<compile_func, LUT_SIZE_C> lut_00, lut_01, lut_10;
    std::array<compile_func, LUT_SIZE> lut_11;

    struct instruction_pattern {
        uint32_t value;
        uint32_t mask;
        typename arch::traits<ARCH>::opcode_e id;
    };

    std::array<std::vector<instruction_pattern>, 4> qlut;

    inline void raise(uint16_t trap_id, uint16_t cause){
        auto trap_val =  0x80ULL << 24 | (cause << 16) | trap_id;
        this->core.reg.trap_state = trap_val;
        this->template get_reg<uint${addrDataWidth}_t>(traits::NEXT_PC) = std::numeric_limits<uint${addrDataWidth}_t>::max();
    }

    inline void leave(unsigned lvl){
        this->core.leave_trap(lvl);
    }

    inline void wait(unsigned type){
        this->core.wait_until(type);
    }

    using yield_t = boost::coroutines2::coroutine<void>::push_type;
    using coro_t = boost::coroutines2::coroutine<void>::pull_type;
    std::vector<coro_t> spawn_blocks;

    template<unsigned W, typename U, typename S = typename std::make_signed<U>::type>
    inline S sext(U from) {
        auto mask = (1ULL<<W) - 1;
        auto sign_mask = 1ULL<<(W-1);
        return (from & mask) | ((from & sign_mask) ? ~mask : 0);
    }
    
    inline void process_spawn_blocks() {
        if(spawn_blocks.size()==0) return;
        for(auto it = std::begin(spawn_blocks); it!=std::end(spawn_blocks);)
             if(*it){
                 (*it)();
                 ++it;
             } else
                 spawn_blocks.erase(it);
    }
<%functions.each{ it.eachLine { %>
    ${it}<%}%>
<%}%>

private:
    /****************************************************************************
     * start opcode definitions
     ****************************************************************************/
    struct instruction_descriptor {
        size_t length;
        uint32_t value;
        uint32_t mask;
        typename arch::traits<ARCH>::opcode_e op;
    };
    struct decoding_tree_node{
        std::vector<instruction_descriptor> instrs;
        std::vector<decoding_tree_node*> children;
        uint32_t submask = std::numeric_limits<uint32_t>::max();
        uint32_t value;
        decoding_tree_node(uint32_t value) : value(value){}
    };

    decoding_tree_node* root {nullptr};
    const std::array<instruction_descriptor, ${instructions.size}> instr_descr = {{
         /* entries are: size, valid value, valid mask, function ptr */<%instructions.each{instr -> %>
        {${instr.length}, ${instr.encoding}, ${instr.mask}, arch::traits<ARCH>::opcode_e::${instr.instruction.name}},<%}%>
    }};

    iss::status fetch_ins(virt_addr_t pc, uint8_t * data){
        auto phys_pc = this->core.v2p(pc);
            if (this->core.read(phys_pc, 4, data) != iss::Ok)  return iss::Err;
        return iss::Ok;
    }
    void populate_decoding_tree(decoding_tree_node* root){
        //create submask
        for(auto instr: root->instrs){
            root->submask &= instr.mask;
        }
        //put each instr according to submask&encoding into children
        for(auto instr: root->instrs){
            bool foundMatch = false;
            for(auto child: root->children){
                //use value as identifying trait
                if(child->value == (instr.value&root->submask)){
                    child->instrs.push_back(instr);
                    foundMatch = true;
                }
            }
            if(!foundMatch){
                decoding_tree_node* child = new decoding_tree_node(instr.value&root->submask);
                child->instrs.push_back(instr);
                root->children.push_back(child);
            }
        }
        root->instrs.clear();
        //call populate_decoding_tree for all children
        if(root->children.size() >1)
            for(auto child: root->children){
                populate_decoding_tree(child);      
            }
        else{
            //sort instrs by value of the mask, this works bc we want to have the least restrictive one last
            std::sort(root->children[0]->instrs.begin(), root->children[0]->instrs.end(), [](const instruction_descriptor& instr1, const instruction_descriptor& instr2) {
            return instr1.mask > instr2.mask;
            }); 
        }
    }
    typename arch::traits<ARCH>::opcode_e  decodeInstr(decoding_tree_node* node, code_word_t word){
        if(!node->children.size()){
            if(node->instrs.size() == 1) return node->instrs[0].op;
            for(auto instr : node->instrs){
                if((instr.mask&word) == instr.value) return instr.op;
            }
        }
        else{
            for(auto child : node->children){
                if (child->value == (node->submask&word)){
                    return decodeInstr(child, word);
                }  
            }  
        }
        return arch::traits<ARCH>::opcode_e::MAX_OPCODE;
    }
};

template <typename CODE_WORD> void debug_fn(CODE_WORD insn) {
    volatile CODE_WORD x = insn;
    insn = 2 * x;
}

template <typename ARCH> vm_impl<ARCH>::vm_impl() { this(new ARCH()); }

// according to
// https://stackoverflow.com/questions/8871204/count-number-of-1s-in-binary-representation
#ifdef __GCC__
constexpr size_t bit_count(uint32_t u) { return __builtin_popcount(u); }
#elif __cplusplus < 201402L
constexpr size_t uCount(uint32_t u) { return u - ((u >> 1) & 033333333333) - ((u >> 2) & 011111111111); }
constexpr size_t bit_count(uint32_t u) { return ((uCount(u) + (uCount(u) >> 3)) & 030707070707) % 63; }
#else
constexpr size_t bit_count(uint32_t u) {
    size_t uCount = u - ((u >> 1) & 033333333333) - ((u >> 2) & 011111111111);
    return ((uCount + (uCount >> 3)) & 030707070707) % 63;
}
#endif

template <typename ARCH>
vm_impl<ARCH>::vm_impl(ARCH &core, unsigned core_id, unsigned cluster_id)
: vm_base<ARCH>(core, core_id, cluster_id) {
    unsigned id=0;
    root = new decoding_tree_node(std::numeric_limits<uint32_t>::max());
    for(auto instr:instr_descr){
        root->instrs.push_back(instr);
    }
    populate_decoding_tree(root);
}

inline bool is_count_limit_enabled(finish_cond_e cond){
    return (cond & finish_cond_e::COUNT_LIMIT) == finish_cond_e::COUNT_LIMIT;
}

inline bool is_jump_to_self_enabled(finish_cond_e cond){
    return (cond & finish_cond_e::JUMP_TO_SELF) == finish_cond_e::JUMP_TO_SELF;
}

template <typename ARCH>
typename vm_base<ARCH>::virt_addr_t vm_impl<ARCH>::execute_inst(finish_cond_e cond, virt_addr_t start, uint64_t icount_limit){
    auto pc=start;
    auto* PC = reinterpret_cast<uint${addrDataWidth}_t*>(this->regs_base_ptr+arch::traits<ARCH>::reg_byte_offsets[arch::traits<ARCH>::PC]);
    auto* NEXT_PC = reinterpret_cast<uint${addrDataWidth}_t*>(this->regs_base_ptr+arch::traits<ARCH>::reg_byte_offsets[arch::traits<ARCH>::NEXT_PC]);
    auto& trap_state = this->core.reg.trap_state;
    auto& icount =  this->core.reg.icount;
    auto& cycle =  this->core.reg.cycle;
    auto& instret =  this->core.reg.instret;
    auto& instr =  this->core.reg.instruction;
    // we fetch at max 4 byte, alignment is 2
    auto *const data = reinterpret_cast<uint8_t*>(&instr);

    while(!this->core.should_stop() &&
            !(is_count_limit_enabled(cond) && icount >= icount_limit)){
        if(fetch_ins(pc, data)!=iss::Ok){
            this->do_sync(POST_SYNC, std::numeric_limits<unsigned>::max());
            pc.val = super::core.enter_trap(std::numeric_limits<uint64_t>::max(), pc.val, 0);
        } else {
            if (is_jump_to_self_enabled(cond) &&
                    (instr == 0x0000006f || (instr&0xffff)==0xa001)) throw simulation_stopped(0); // 'J 0' or 'C.J 0'
            auto inst_id = decodeInstr(root, instr);
            // pre execution stuff
             this->core.reg.last_branch = 0;
            if(this->sync_exec && PRE_SYNC) this->do_sync(PRE_SYNC, static_cast<unsigned>(inst_id));
            switch(inst_id){<%instructions.eachWithIndex{instr, idx -> %>
            case arch::traits<ARCH>::opcode_e::${instr.name}: {
                <%instr.fields.eachLine{%>${it}
                <%}%>if(this->disass_enabled){
                    /* generate console output when executing the command */<%instr.disass.eachLine{%>
                    ${it}<%}%>
                }
                // used registers<%instr.usedVariables.each{ k,v->
                if(v.isArray) {%>
                auto* ${k} = reinterpret_cast<uint${nativeTypeSize(v.type.size)}_t*>(this->regs_base_ptr+arch::traits<ARCH>::reg_byte_offsets[arch::traits<ARCH>::${k}0]);<% }else{ %> 
                auto* ${k} = reinterpret_cast<uint${nativeTypeSize(v.type.size)}_t*>(this->regs_base_ptr+arch::traits<ARCH>::reg_byte_offsets[arch::traits<ARCH>::${k}]);
                <%}}%>// calculate next pc value
                *NEXT_PC = *PC + ${instr.length/8};
                // execute instruction<%instr.behavior.eachLine{%>
                ${it}<%}%>
                TRAP_${instr.name}:break;
            }// @suppress("No break at end of case")<%}%>
            default: {
                *NEXT_PC = *PC + ((instr & 3) == 3 ? 4 : 2);
                raise(0,  2);
            }
            }
            // post execution stuff
            process_spawn_blocks();
            if(this->sync_exec && POST_SYNC) this->do_sync(POST_SYNC, static_cast<unsigned>(inst_id));
            // if(!this->core.reg.trap_state) // update trap state if there is a pending interrupt
            //    this->core.reg.trap_state =  this->core.reg.pending_trap;
            // trap check
            if(trap_state!=0){
                super::core.enter_trap(trap_state, pc.val, instr);
            } else {
                icount++;
                instret++;
            }
            cycle++;
            pc.val=*NEXT_PC;
            this->core.reg.PC = this->core.reg.NEXT_PC;
            this->core.reg.trap_state =  this->core.reg.pending_trap;
        }
    }
    return pc;
}

}

template <>
std::unique_ptr<vm_if> create<arch::${coreDef.name.toLowerCase()}>(arch::${coreDef.name.toLowerCase()} *core, unsigned short port, bool dump) {
    auto ret = new ${coreDef.name.toLowerCase()}::vm_impl<arch::${coreDef.name.toLowerCase()}>(*core, dump);
    if (port != 0) debugger::server<debugger::gdb_session>::run_server(ret, port);
    return std::unique_ptr<vm_if>(ret);
}
} // namespace interp
} // namespace iss