Fix unsigned multiplication in MIPS simulator (add assembler regression test).

runtime/vm/simulator_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 <setjmp.h>
 #include <stdlib.h>
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_MIPS)
 
@@ skipping 76 matching lines @@
   void Debug();
   char* ReadLine(const char* prompt);
 
  private:
   Simulator* sim_;
 
   bool GetValue(char* desc, uint32_t* value);
   bool GetFValue(char* desc, double* value);
   bool GetDValue(char* desc, double* value);
 
+  static const int32_t kSimulatorBreakpointInstruction =
+      Instr::kBreakPointInstruction |
+      (Instr::kSimulatorBreakCode << kBreakCodeShift);
+
   // Set or delete a breakpoint. Returns true if successful.
   bool SetBreakpoint(Instr* breakpc);
   bool DeleteBreakpoint(Instr* breakpc);
 
   // Undo and redo all breakpoints. This is needed to bracket disassembly and
   // execution to skip past breakpoints when run from the debugger.
   void UndoBreakpoints();
   void RedoBreakpoints();
 };
 
@@ skipping 168 matching lines @@
 
 void SimulatorDebugger::UndoBreakpoints() {
   if (sim_->break_pc_ != NULL) {
     sim_->break_pc_->SetInstructionBits(sim_->break_instr_);
   }
 }
 
 
 void SimulatorDebugger::RedoBreakpoints() {
   if (sim_->break_pc_ != NULL) {
-    sim_->break_pc_->SetInstructionBits(Instr::kBreakPointInstruction);
+    sim_->break_pc_->SetInstructionBits(kSimulatorBreakpointInstruction);
   }
 }
 
 
 void SimulatorDebugger::Debug() {
   intptr_t last_pc = -1;
   bool done = false;
 
 #define COMMAND_SIZE 63
 #define ARG_SIZE 255
@@ skipping 899 matching lines @@
       }
 
       // Return. Subtract to account for pc_ increment after return.
       set_pc(saved_ra - Instr::kInstrSize);
     } else {
       // Coming via long jump from a throw. Continue to exception handler.
       set_top_exit_frame_info(0);
       // Adjust for extra pc increment.
       set_pc(get_pc() - Instr::kInstrSize);
     }
+  } else if (instr->BreakCodeField() == Instr::kSimulatorBreakCode) {
+    SimulatorDebugger dbg(this);
+    dbg.Stop(instr, "breakpoint");
+    // Adjust for extra pc increment.
+    set_pc(get_pc() - Instr::kInstrSize);
   } else {
     SimulatorDebugger dbg(this);
-    dbg.Stop(instr, "breakpoint");
+    set_pc(get_pc() + Instr::kInstrSize);
+    char buffer[32];
+    snprintf(buffer, sizeof(buffer), "break #0x%x", instr->BreakCodeField());
+    dbg.Stop(instr, buffer);
     // Adjust for extra pc increment.
     set_pc(get_pc() - Instr::kInstrSize);
   }
 }
 
 
 void Simulator::DecodeSpecial(Instr* instr) {
   ASSERT(instr->OpcodeField() == SPECIAL);
   switch (instr->FunctionField()) {
     case ADDU: {
@@ skipping 140 matching lines @@
       ASSERT(instr->RdField() == 0);
       ASSERT(instr->SaField() == 0);
       // Format(instr, "mflo 'rd");
       set_lo_register(get_register(instr->RsField()));
       break;
     }
     case MULT: {
       ASSERT(instr->RdField() == 0);
       ASSERT(instr->SaField() == 0);
       // Format(instr, "mult 'rs, 'rt");
-      int64_t rs = static_cast<int64_t>(get_register(instr->RsField()));
-      int64_t rt = static_cast<int64_t>(get_register(instr->RtField()));
+      int64_t rs = get_register(instr->RsField());
+      int64_t rt = get_register(instr->RtField());
       int64_t res = rs * rt;
       set_hi_register(Utils::High32Bits(res));
       set_lo_register(Utils::Low32Bits(res));
       break;
     }
     case MULTU: {
       ASSERT(instr->RdField() == 0);
       ASSERT(instr->SaField() == 0);
       // Format(instr, "multu 'rs, 'rt");
-      uint64_t rs = static_cast<uint64_t>(get_register(instr->RsField()));
-      uint64_t rt = static_cast<uint64_t>(get_register(instr->RtField()));
+      uint64_t rs = static_cast<uint32_t>(get_register(instr->RsField()));
+      uint64_t rt = static_cast<uint32_t>(get_register(instr->RtField()));
       uint64_t res = rs * rt;
       set_hi_register(Utils::High32Bits(res));
       set_lo_register(Utils::Low32Bits(res));
       break;
     }
     case NOR: {
       ASSERT(instr->SaField() == 0);
       // Format(instr, "nor 'rd, 'rs, 'rt");
       int32_t rs_val = get_register(instr->RsField());
       int32_t rt_val = get_register(instr->RtField());
@@ skipping 958 matching lines @@
   set_register(kExceptionObjectReg, bit_cast<int32_t>(raw_exception));
   set_register(kStackTraceObjectReg, bit_cast<int32_t>(raw_stacktrace));
   buf->Longjmp();
 }
 
 }  // namespace dart
 
 #endif  // !defined(HOST_ARCH_MIPS)
 
 #endif  // defined TARGET_ARCH_MIPS