ARM backend support for pld (preload data) instruction

src/arm/simulator-arm.cc

Index: src/arm/simulator-arm.cc
===================================================================
--- src/arm/simulator-arm.cc	(revision 13713)
+++ src/arm/simulator-arm.cc	(working copy)
@@ -3248,7 +3248,9 @@
     PrintF("  0x%08x  %s\n", reinterpret_cast<intptr_t>(instr), buffer.start());
   }
   if (instr->ConditionField() == kSpecialCondition) {
-    UNIMPLEMENTED();
+    if (!instr->IsPld()) {

[Sven Panne, 2013/02/28 07:36:11]

Hmmm, shouldn't we at least do the load here in the case of pld? If e.g. the
address is nonsense, we would see the effect here.

[danno, 2013/02/28 07:53:55]

I'm not sure that's the right thing to do.

From ARM ARM:

"The Preload instructions are hints, and so implementations can treat them as
NOPs without affecting the functional behavior of the device."

This suggests that bad addresses are simply ignored and do not cause exceptions,
so dereffing the address and possibly crashing doesn't seem spec-conform.

Adding some other ARM-experts

On 2013/02/28 07:36:11, Sven Panne wrote:

+      UNIMPLEMENTED();
+    }
   } else if (ConditionallyExecute(instr)) {
     switch (instr->TypeValue()) {
       case 0: