s390: introduce DUMY opcode for special use.

src/s390/assembler-s390.cc

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions
 // are met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 2994 matching lines @@
 // end of S390instructions
 
 bool Assembler::IsNop(SixByteInstr instr, int type) {
   DCHECK((0 == type) || (DEBUG_BREAK_NOP == type));
   if (DEBUG_BREAK_NOP == type) {
     return ((instr & 0xffffffff) == 0xa53b0000);  // oill r3, 0
   }
   return ((instr & 0xffff) == 0x1800);  // lr r0,r0
 }
 
+// dummy instruction reserved for special use.
+void Assembler::dumy(int r1, int x2, int b2, int d2) {
+#if defined(USE_SIMULATOR)
+  int op = 0xE353;
+  uint64_t code = (static_cast<uint64_t>(op & 0xFF00)) * B32 |
+                  (static_cast<uint64_t>(r1) & 0xF) * B36 |
+                  (static_cast<uint64_t>(x2) & 0xF) * B32 |
+                  (static_cast<uint64_t>(b2) & 0xF) * B28 |
+                  (static_cast<uint64_t>(d2 & 0x0FFF)) * B16 |
+                  (static_cast<uint64_t>(d2 & 0x0FF000)) >> 4 |
+                  (static_cast<uint64_t>(op & 0x00FF));
+  emit6bytes(code);
+#endif
+}
+
 void Assembler::GrowBuffer(int needed) {
   if (!own_buffer_) FATAL("external code buffer is too small");
 
   // Compute new buffer size.
   CodeDesc desc;  // the new buffer
   if (buffer_size_ < 4 * KB) {
     desc.buffer_size = 4 * KB;
   } else if (buffer_size_ < 1 * MB) {
     desc.buffer_size = 2 * buffer_size_;
   } else {
@@ skipping 103 matching lines @@
                             SKIP_ICACHE_FLUSH);
     }
 
     reloc_info_writer.Write(&rinfo);
   }
 }
 
 }  // namespace internal
 }  // namespace v8
 #endif  // V8_TARGET_ARCH_S390