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  1. #include<cstdlib>
  2. #include<cstdint>
  3. #include<cstddef>
  4. #include<cstdio>
  5. #include<initializer_list>
  6.  
  7.  
  8.  
  9. namespace test{
  10.  
  11.  
  12. enum class
  13. opcode
  14. {
  15.   nop,
  16.   addi,
  17.   ori,
  18.   lui,
  19.   lt,
  20.   brz,
  21.   brnz,
  22.   exi,
  23.  
  24. };
  25.  
  26.  
  27. struct nop{};
  28. struct exi{};
  29.  
  30. struct
  31. addi
  32. {
  33.   uint8_t  r1;
  34.   uint8_t  r2;
  35.  
  36.   int16_t  imm;
  37.  
  38. };
  39.  
  40.  
  41. struct
  42. lui
  43. {
  44.   uint8_t  r1;
  45.  
  46.   uint16_t  imm;
  47.  
  48. };
  49.  
  50.  
  51. struct
  52. ori
  53. {
  54.   uint8_t  r1;
  55.   uint8_t  r2;
  56.  
  57.   uint16_t  imm;
  58.  
  59. };
  60.  
  61.  
  62. struct
  63. lt
  64. {
  65.   uint8_t  r1;
  66.   uint8_t  r2;
  67.   uint8_t  r3;
  68.  
  69. };
  70.  
  71.  
  72. struct
  73. brz
  74. {
  75.   uint8_t  r1;
  76.  
  77.   int16_t  offset;
  78.  
  79. };
  80.  
  81.  
  82. struct
  83. brnz
  84. {
  85.   uint8_t  r1;
  86.  
  87.   int16_t  offset;
  88.  
  89. };
  90.  
  91.  
  92. struct
  93. inst_code
  94. {
  95.   uint32_t  m_data=0;
  96.  
  97.   static constexpr uint32_t  to_code(opcode  c) noexcept{return static_cast<int>(c)<<26;}
  98.  
  99. public:
  100.   constexpr inst_code() noexcept{}
  101.  
  102.   constexpr inst_code(test::addi  addi) noexcept:
  103.   m_data(to_code(opcode::addi)|(addi.r1<<21)|(addi.r2<<16)|(addi.imm&0xFFFF)){}
  104.  
  105.   constexpr inst_code(test::ori  ori) noexcept:
  106.   m_data(to_code(opcode::ori)|(ori.r1<<21)|(ori.r2<<16)|(ori.imm&0xFFFF)){}
  107.  
  108.   constexpr inst_code(test::lui  lui) noexcept:
  109.   m_data(to_code(opcode::lui)|(lui.r1<<21)|(lui.imm&0xFFFF)){}
  110.  
  111.   constexpr inst_code(test::lt  lt) noexcept:
  112.   m_data(to_code(opcode::lt)|(lt.r1<<21)|(lt.r2<<16)|lt.r3){}
  113.  
  114.   constexpr inst_code(test::brz  brz) noexcept:
  115.   m_data(to_code(opcode::brz)|(brz.r1<<21)|(brz.offset&0xFFFF)){}
  116.  
  117.   constexpr inst_code(test::brnz  brnz) noexcept:
  118.   m_data(to_code(opcode::brnz)|(brnz.r1<<21)|(brnz.offset&0xFFFF)){}
  119.  
  120.   constexpr inst_code(test::exi  exi) noexcept:
  121.   m_data(to_code(opcode::exi)){}
  122.  
  123.   constexpr opcode  get_opcode() const noexcept
  124.   {
  125.     return static_cast<opcode>(m_data>>26);
  126.   }
  127.  
  128.   constexpr uint8_t  get_r1() const noexcept{return (m_data>>21)&0x1F;}
  129.   constexpr uint8_t  get_r2() const noexcept{return (m_data>>16)&0x1F;}
  130.   constexpr uint8_t  get_r3() const noexcept{return (m_data    )&0x1F;}
  131.  
  132.   constexpr uint16_t  get_imm_u16() const noexcept{return (m_data&0xFFFF);}
  133.   constexpr  int16_t  get_imm_s16() const noexcept{return (m_data&0xFFFF);}
  134.  
  135. };
  136.  
  137.  
  138. class
  139. register_set
  140. {
  141.   static constexpr int  number_of_registers = 32;
  142.  
  143.   int32_t  m_registers[number_of_registers] = {0};
  144.  
  145. public:
  146.   int32_t  get(uint8_t  i            ) const noexcept{return m_registers[i]    ;}
  147.   void     put(uint8_t  i, int32_t  v)       noexcept{       m_registers[i] = v;}
  148.  
  149.   void  addi(uint8_t  dst, uint8_t  src, int16_t  imm) noexcept
  150.   {
  151.     m_registers[dst] = m_registers[src]+imm;
  152.   }
  153.  
  154.   void  ori(uint8_t  dst, uint8_t  src, uint16_t  imm) noexcept
  155.   {
  156.     m_registers[dst] = m_registers[src]|imm;
  157.   }
  158.  
  159.   void  lui(uint8_t  dst, int16_t  imm) noexcept
  160.   {
  161.     m_registers[dst] = imm<<16;
  162.   }
  163.  
  164.   void  lt(uint8_t  dst, uint8_t  src1, uint8_t  src2) noexcept
  165.   {
  166.     m_registers[dst] = (m_registers[src1] < m_registers[src2])? 1:0;
  167.   }
  168.  
  169. };
  170.  
  171.  
  172. class
  173. memory_space
  174. {
  175.   static constexpr size_t  data_size = 256;
  176.  
  177.   uint8_t  m_data[data_size];
  178.  
  179. public:
  180.   memory_space() noexcept{}
  181.   memory_space(std::initializer_list<inst_code>  ls) noexcept{assign(ls);}
  182.  
  183.   void  assign(std::initializer_list<inst_code>  ls) noexcept
  184.   {
  185.     auto  p = reinterpret_cast<inst_code*>(&m_data[0]);
  186.  
  187.       for(auto  icode: ls)
  188.       {
  189.         *p++ = icode;
  190.       }
  191.   }
  192.  
  193.  
  194.   inst_code  fetch(uint32_t  pc) const noexcept{return *reinterpret_cast<const inst_code*>(&m_data[pc&~3]);}
  195.  
  196.   size_t  size() const noexcept{return data_size;}
  197.  
  198.   uint8_t&   get_u8( uint32_t  address) noexcept{return m_data[address];}
  199.    int8_t&   get_s8( uint32_t  address) noexcept{return reinterpret_cast<  int8_t&>(m_data[address   ]);}
  200.   uint16_t&  get_u16(uint32_t  address) noexcept{return reinterpret_cast<uint16_t&>(m_data[address&~1]);}
  201.    int16_t&  get_s16(uint32_t  address) noexcept{return reinterpret_cast< int16_t&>(m_data[address&~1]);}
  202.   uint32_t&  get_u32(uint32_t  address) noexcept{return reinterpret_cast<uint32_t&>(m_data[address&~3]);}
  203.    int32_t&  get_s32(uint32_t  address) noexcept{return reinterpret_cast< int32_t&>(m_data[address&~3]);}
  204.  
  205. };
  206.  
  207.  
  208. class
  209. vm
  210. {
  211.   uint32_t  m_pc=0;
  212.  
  213.   register_set*  m_register_set=nullptr;
  214.   memory_space*  m_memory_space=nullptr;
  215.  
  216.   bool  m_is_exited=false;
  217.  
  218. public:
  219.   vm(register_set&  regset, memory_space&  memsp) noexcept:
  220.   m_register_set(&regset), m_memory_space(&memsp){}
  221.  
  222.   bool  is_exited() const noexcept{return m_is_exited;}
  223.  
  224.   uint32_t  get_pc() const noexcept{return m_pc;}
  225.  
  226.   void  step() noexcept
  227.   {
  228.     auto  inst = m_memory_space->fetch(m_pc);
  229.  
  230.     m_pc += 4;
  231.  
  232.       switch(inst.get_opcode())
  233.       {
  234.     case(opcode::nop):
  235.         break;
  236.     case(opcode::addi):
  237.         m_register_set->addi(inst.get_r1(),inst.get_r2(),inst.get_imm_s16());
  238.         break;
  239.     case(opcode::ori):
  240.         m_register_set->ori(inst.get_r1(),inst.get_r2(),inst.get_imm_u16());
  241.         break;
  242.     case(opcode::lui):
  243.         m_register_set->lui(inst.get_r1(),inst.get_imm_u16());
  244.         break;
  245.     case(opcode::lt):
  246.         m_register_set->lt(inst.get_r1(),inst.get_r2(),inst.get_r3());
  247.         break;
  248.     case(opcode::brz):
  249.           if(m_register_set->get(inst.get_r1()) == 0)
  250.           {
  251.             m_pc += inst.get_imm_s16()<<2;
  252.           }
  253.         break;
  254.     case(opcode::brnz):
  255.           if(m_register_set->get(inst.get_r1()))
  256.           {
  257.             m_pc += inst.get_imm_s16()<<2;
  258.           }
  259.         break;
  260.     case(opcode::exi):
  261.         m_is_exited = true;
  262.         break;
  263.     default:
  264.         printf("[%d]",static_cast<int>(inst.get_opcode()));
  265.       }
  266.   }
  267.  
  268. };
  269.  
  270.  
  271.  
  272. }
  273.  
  274.  
  275. int
  276. main(int  argc, char**  argv)
  277. {
  278.   using namespace test;
  279.  
  280.   bool  pr = (argc > 1);
  281.  
  282.   test::memory_space  mem({
  283.     inst_code(addi{1,0,0}),
  284.     inst_code(lui{2,0xFF}),
  285.     inst_code(ori{2,2,0xFFFF}),
  286.     inst_code(lt{3,1,2}),
  287.     inst_code(brz{3,2}),
  288.  
  289.     inst_code(addi{1,1,1}),
  290.  
  291.     inst_code(brz{0,-4}),
  292.     inst_code(exi{}),
  293.   });
  294.  
  295.  
  296.   test::register_set  regset;
  297.  
  298.   test::vm  vm(regset,mem);
  299.  
  300.     while(!vm.is_exited())
  301.     {
  302. if(pr){printf("%8d",vm.get_pc());}
  303.       vm.step();
  304.  
  305. if(pr){printf(" %d\n",regset.get(1));}
  306.     }
  307.  
  308.  
  309.  
  310.   return 0;
  311. }
  312.  
  313.  
  314.  
  315.  
Success #stdin #stdout 0.31s 4420KB
comments (?)
stdin 
Standard input is empty
stdout 
Standard output is empty
https://ideone.com/o41GKB
language:
C++14 (clang 8.0)
created:
6 years ago
visibility:
public

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