lab_fetch.tlv

\m4_TLV_version 1d: tl-x.org
\SV
   // This code can be found in: https://github.com/stevehoover/RISC-V_MYTH_Workshop
   
   m4_include_lib(['https://raw.githubusercontent.com/stevehoover/RISC-V_MYTH_Workshop/c1719d5b338896577b79ee76c2f443ca2a76e14f/tlv_lib/risc-v_shell_lib.tlv'])

\SV
   m4_makerchip_module   // (Expanded in Nav-TLV pane.)
\TLV

   // /====================\
   // | Sum 1 to 9 Program |
   // \====================/
   //
   // Program for MYTH Workshop to test RV32I
   // Add 1,2,3,...,9 (in that order).
   //
   // Regs:
   //  r10 (a0): In: 0, Out: final sum
   //  r12 (a2): 10
   //  r13 (a3): 1..10
   //  r14 (a4): Sum
   // 
   // External to function:
   m4_asm(ADD, r10, r0, r0)             // Initialize r10 (a0) to 0.
   // Function:
   m4_asm(ADD, r14, r10, r0)            // Initialize sum register a4 with 0x0
   m4_asm(ADDI, r12, r10, 1010)         // Store count of 10 in register a2.
   m4_asm(ADD, r13, r10, r0)            // Initialize intermediate sum register a3 with 0
   // Loop:
   m4_asm(ADD, r14, r13, r14)           // Incremental addition
   m4_asm(ADDI, r13, r13, 1)            // Increment intermediate register by 1
   m4_asm(BLT, r13, r12, 1111111111000) // If a3 is less than a2, branch to label named <loop>
   m4_asm(ADD, r10, r14, r0)            // Store final result to register a0 so that it can be read by main program
   
   // Optional:
   // m4_asm(JAL, r7, 00000000000000000000) // Done. Jump to itself (infinite loop). (Up to 20-bit signed immediate plus implicit 0 bit (unlike JALR) provides byte address; last immediate bit should also be 0)
   m4_define_hier(['M4_IMEM'], M4_NUM_INSTRS)

   |cpu
      @0
         $reset = *reset;
         $pc[31:0] = >>1$reset ? 32'b0 : (>>1$pc + 32'd4);
         
      @1
         $imem_rd_en = !$reset;
         $imem_rd_addr[M4_IMEM_INDEX_CNT-1:0] = $pc[M4_IMEM_INDEX_CNT+1:2];
         $instr[31:0] = $imem_rd_data[31:0]; 
   
   // Assert these to end simulation (before Makerchip cycle limit).
   *passed = *cyc_cnt > 40;
   *failed = 1'b0;
   
   // Macro instantiations for:
   //  o instruction memory
   //  o register file
   //  o data memory
   |cpu
      m4+imem(@1)    // Args: (read stage)
      //m4+rf(@1, @1)  // Args: (read stage, write stage) - if equal, no register bypass is required
      //m4+dmem(@4)    // Args: (read/write stage)

\SV
   endmodule