Merge pull request #22 from ucb-bar/gemmini-fence

Add gemmini fence instruction

Author: jerryz123

gemmini/gemmini.cc

@@ -1211,6 +1211,8 @@ reg_t gemmini_t::CUSTOMFN(XCUSTOM_ACC)(rocc_insn_t insn, reg_t xs1, reg_t xs2) {
   //==========================================================================
   else if (insn.funct == flush_funct) {
     dprintf("GEMMINI: flush\n");
+  } else if (insn.funct == fence_funct) {
+    dprintf("GEMMINI: fence\n");
   } else {
     dprintf("GEMMINI: encountered unknown instruction with funct: %d\n", insn.funct);
     illegal_instruction();

gemmini/gemmini.h

@@ -136,6 +136,7 @@ class gemmini_t : public rocc_t
   const unsigned loop_ws_config_addrs_DC_funct = 11;
   const unsigned loop_ws_config_strides_AB_funct = 12;
   const unsigned loop_ws_config_strides_DC_funct = 13;
+
   const unsigned loop_conv_ws_funct = 15;
   const unsigned loop_conv_ws_config_1_funct = 16;
   const unsigned loop_conv_ws_config_2_funct = 17;
@@ -144,6 +145,8 @@ class gemmini_t : public rocc_t
   const unsigned loop_conv_ws_config_5_funct = 20;
   const unsigned loop_conv_ws_config_6_funct = 21;
 
+  const unsigned fence_funct = 127;
+
   //==========================================================================
   // gemmini-cisc opcodes
   //==========================================================================