Implement memory operands for instructions in the x64 assembler.

src/x64/assembler-x64-inl.h

Index: src/x64/assembler-x64-inl.h
===================================================================
--- src/x64/assembler-x64-inl.h	(revision 2061)
+++ src/x64/assembler-x64-inl.h	(working copy)
@@ -173,13 +173,32 @@
   return reinterpret_cast<Object**>(pc_ + 1);
 }
 
+// -----------------------------------------------------------------------------
+// Implementation of Operand
 
+Operand::Operand(Register base, int32_t disp) {
+  len_ = 1;
+  if (base.is(rsp) || base.is(r12)) {
+    // SIB byte is needed to encode (rsp + offset) or (r12 + offset).
+    set_sib(times_1, rsp, base);
+  }
+
+  if (disp == 0 && !base.is(rbp) && !base.is(r13)) {
+    set_modrm(0, rsp);
+  } else if (is_int8(disp)) {
+    set_modrm(1, base);
+    set_disp8(disp);
+  } else {
+    set_modrm(2, base);
+    set_disp32(disp);
+  }
+}
+
 void Operand::set_modrm(int mod, Register rm) {
   ASSERT((mod & -4) == 0);
   buf_[0] = mod << 6 | (rm.code() & 0x7);
   // Set REX.B to the high bit of rm.code().
   rex_ |= (rm.code() >> 3);
-  len_ = 1;
 }
 
 
@@ -193,8 +212,15 @@
   len_ = 2;
 }
 
+void Operand::set_disp8(int disp) {
+  ASSERT(is_int8(disp));
+  ASSERT(len_ == 1 || len_ == 2);
+  int8_t* p = reinterpret_cast<int8_t*>(&buf_[len_]);
+  *p = disp;
+  len_ += sizeof(int8_t);
+}
 
-void Operand::set_disp32(int32_t disp) {
+void Operand::set_disp32(int disp) {
   ASSERT(len_ == 1 || len_ == 2);
   int32_t* p = reinterpret_cast<int32_t*>(&buf_[len_]);
   *p = disp;
@@ -202,11 +228,6 @@
 }
 
 
-Operand::Operand(Register reg) {
-  // reg
-  set_modrm(3, reg);
-}
-
 } }  // namespace v8::internal
 
 #endif  // V8_X64_ASSEMBLER_X64_INL_H_