ARM backend support for pld (preload data) instruction

src/arm/assembler-arm.cc

Index: src/arm/assembler-arm.cc
===================================================================
--- src/arm/assembler-arm.cc	(revision 13713)
+++ src/arm/assembler-arm.cc	(working copy)
@@ -1495,6 +1495,31 @@
 }
 
 
+// Preload data instruction
+void Assembler::pld(const MemOperand& src) {
+  Instr instr = kCondMask | B26 | B | L | kRdMask;
+  int am = src.am_;
+  ASSERT((am & (P | W)) == P);
+  if (!src.rm_.is_valid()) {
+    // Immediate offset.
+    int offset_12 = src.offset_;
+    if (offset_12 < 0) {
+      offset_12 = -offset_12;
+      am ^= U;
+    }
+    ASSERT(offset_12 >= 0);  // no masking needed
+    instr |= offset_12;
+  } else {
+    // Register offset (shift_imm_ and shift_op_ are 0) or scaled
+    // register offset the constructors make sure than both shift_imm_
+    // and shift_op_ are initialized.
+    ASSERT(!src.rm_.is(pc));
+    instr |= B25 | src.shift_imm_*B7 | src.shift_op_ | src.rm_.code();
+  }
+  emit(instr | am | src.rn_.code()*B16);
+}
+
+
 // Load/Store instructions.
 void Assembler::ldr(Register dst, const MemOperand& src, Condition cond) {
   if (dst.is(pc)) {