src/hotspot/cpu/x86/assembler_x86.cpp

*** 8424,8439 ****
--- 8424,8472 ----
    prefix(REX_W);
    emit_int8((unsigned char)0x99);
  }
  
  void Assembler::clflush(Address adr) {
+   assert(VM_Version::supports_clflush(), "should do");
    prefix(adr);
    emit_int8(0x0F);
    emit_int8((unsigned char)0xAE);
    emit_operand(rdi, adr);
  }
  
+ #ifdef _LP64
+ void Assembler::clflushopt(Address adr) {
+   assert(VM_Version::supports_clflushopt(), "should do!");
+   // adr should be base reg only with no index or offset
+   assert(adr.index() == noreg, "index should be noreg");
+   assert(adr.scale() == Address::no_scale, "scale should be no_scale");
+   assert(adr.disp() == 0, "displacement should be 0");
+   // prefix is 0x66
+   emit_int8(0x66);
+   // opcode family is 0x0f 0xAE
+   emit_int8(0x0F);
+   emit_int8((unsigned char)0xAE);
+   // extended opcode byte is 7 == rdi
+   emit_operand(rdi, adr);
+ }
+ 
+ void Assembler::clwb(Address adr) {
+   assert(VM_Version::supports_clwb(), "should do!");
+   // adr should be base reg only with no index or offset
+   assert(adr.index() == noreg, "index should be noreg");
+   assert(adr.scale() == Address::no_scale, "scale should be no_scale");
+   assert(adr.disp() == 0, "displacement should be 0");
+   // prefix is 0x66
+   emit_int8(0x66);
+   // opcode family is 0x0f 0xAE
+   emit_int8(0x0F);
+   emit_int8((unsigned char)0xAE);
+   // extended opcode byte is 6 == rsi
+   emit_operand(rsi, adr);
+ }
+ #endif
+ 
  void Assembler::cmovq(Condition cc, Register dst, Register src) {
    int encode = prefixq_and_encode(dst->encoding(), src->encoding());
    emit_int8(0x0F);
    emit_int8(0x40 | cc);
    emit_int8((unsigned char)(0xC0 | encode));