Simplifies MIPS LoadWordFromPoolOffset

runtime/vm/assembler_mips.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/assembler.h"
 
 namespace dart {
@@ skipping 11 matching lines @@
   }
 }
 
 
 void Assembler::Bind(Label* label) {
   ASSERT(!label->IsBound());
   int bound_pc = buffer_.Size();
   while (label->IsLinked()) {
     const int32_t position = label->Position();
     const int32_t next = buffer_.Load<int32_t>(position);
-    // Reletive destination from an instruction after the branch.
+    // Relative destination from an instruction after the branch.
     const int32_t dest = bound_pc - (position + Instr::kInstrSize);
     const int32_t encoded = Assembler::EncodeBranchOffset(dest, next);
     buffer_.Store<int32_t>(position, encoded);
     label->position_ = Assembler::DecodeBranchOffset(next);
   }
   label->BindTo(bound_pc);
   delay_slot_available_ = false;
 }
 
 
@@ skipping 12 matching lines @@
   // Sign-extend, left-shift by 2.
   return (((instr & kBranchOffsetMask) << 16) >> 14);
 }
 
 
 void Assembler::LoadWordFromPoolOffset(Register rd, int32_t offset) {
   ASSERT(rd != PP);
   if (Address::CanHoldOffset(offset)) {
     lw(rd, Address(PP, offset));
   } else {
-    const uint16_t offset_low = Utils::Low16Bits(offset);
-    const uint16_t offset_high = Utils::High16Bits(offset);
+    const int16_t offset_low = Utils::Low16Bits(offset);  // Signed.
+    offset -= offset_low;
+    const uint16_t offset_high = Utils::High16Bits(offset);  // Unsigned.
     if (offset_high != 0) {
       lui(rd, Immediate(offset_high));
-      if (Address::CanHoldOffset(offset_low)) {
-        addu(rd, rd, PP);
-        lw(rd, Address(rd, offset_low));
-      } else {
-        ori(rd, rd, Immediate(offset_low));
-        addu(rd, rd, PP);
-        lw(rd, Address(rd));
-      }
+      addu(rd, rd, PP);
+      lw(rd, Address(rd, offset_low));
     } else {
-      ori(rd, ZR, Immediate(offset_low));
-      addu(rd, rd, PP);
-      lw(rd, Address(rd));
+      lw(rd, Address(PP, offset_low));
     }
   }
 }
 
 
 int32_t Assembler::AddObject(const Object& obj) {
   ASSERT(obj.IsNotTemporaryScopedHandle());
   ASSERT(obj.IsOld());
   if (object_pool_.IsNull()) {
     // The object pool cannot be used in the vm isolate.
@@ skipping 35 matching lines @@
   b(&stop);
   Emit(reinterpret_cast<int32_t>(message));
   Bind(&stop);
   break_(Instr::kStopMessageCode);
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS