dummy_rocc/dummy_rocc.cc

   1 #include "rocc.h"
   2 #include "mmu.h"
   3 #include <cstring>
   4
   5 class dummy_rocc_t : public rocc_t
   6 {
   7  public:
   8   const char* name() { return "dummy_rocc"; }
   9
  10   reg_t custom0(rocc_insn_t insn, reg_t xs1, reg_t xs2)
  11   {
  12     reg_t prev_acc = acc[insn.rs2];
  13
  14     if (insn.rs2 >= num_acc)
  15       illegal_instruction();
  16
  17     switch (insn.funct)
  18     {
  19       case 0: // acc <- xs1
  20         acc[insn.rs2] = xs1;
  21         break;
  22       case 1: // xd <- acc (the only real work is the return statement below)
  23         break;
  24       case 2: // acc[rs2] <- Mem[xs1]
  25         acc[insn.rs2] = p->get_mmu()->load_uint64(xs1);
  26         break;
  27       case 3: // acc[rs2] <- accX + xs1
  28         acc[insn.rs2] += xs1;
  29         break;
  30       default:
  31         illegal_instruction();
  32     }
  33
  34     return prev_acc; // in all cases, xd <- previous value of acc[rs2]
  35   }
  36
  37   dummy_rocc_t()
  38   {
  39     memset(acc, 0, sizeof(acc));
  40   }
  41
  42  private:
  43   static const int num_acc = 4;
  44   reg_t acc[num_acc];
  45 };
  46
  47 REGISTER_EXTENSION(dummy_rocc, []() { return new dummy_rocc_t; })