MIPS port initial commit

src/mips/simulator-mips.h

Index: src/mips/simulator-mips.h
===================================================================
--- src/mips/simulator-mips.h	(revision 0)
+++ src/mips/simulator-mips.h	(revision 0)
@@ -0,0 +1,311 @@
+// Copyright 2010 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+
+// Declares a Simulator for MIPS instructions if we are not generating a native
+// MIPS binary. This Simulator allows us to run and debug MIPS code generation
+// on regular desktop machines.
+// V8 calls into generated code by "calling" the CALL_GENERATED_CODE macro,
+// which will start execution in the Simulator or forwards to the real entry
+// on a MIPS HW platform.
+
+#ifndef V8_MIPS_SIMULATOR_MIPS_H_
+#define V8_MIPS_SIMULATOR_MIPS_H_
+
+#include "allocation.h"
+
+#if defined(__mips)
+
+// When running without a simulator we call the entry directly.
+#define CALL_GENERATED_CODE(entry, p0, p1, p2, p3, p4) \
+  entry(p0, p1, p2, p3, p4);
+
+// The stack limit beyond which we will throw stack overflow errors in
+// generated code. Because generated code on mips uses the C stack, we
+// just use the C stack limit.
+class SimulatorStack : public v8::internal::AllStatic {
+ public:
+  static inline uintptr_t JsLimitFromCLimit(uintptr_t c_limit) {
+    return c_limit;
+  }
+
+  static inline uintptr_t RegisterCTryCatch(uintptr_t try_catch_address) {
+    return try_catch_address;
+  }
+
+  static inline void UnregisterCTryCatch() { }
+};
+
+// Calculated the stack limit beyond which we will throw stack overflow errors.
+// This macro must be called from a C++ method. It relies on being able to take
+// the address of "this" to get a value on the current execution stack and then
+// calculates the stack limit based on that value.
+// NOTE: The check for overflow is not safe as there is no guarantee that the
+// running thread has its stack in all memory up to address 0x00000000.
+#define GENERATED_CODE_STACK_LIMIT(limit) \
+  (reinterpret_cast<uintptr_t>(this) >= limit ? \
+      reinterpret_cast<uintptr_t>(this) - limit : 0)
+
+// Call the generated regexp code directly. The entry function pointer should
+// expect seven int/pointer sized arguments and return an int.
+#define CALL_GENERATED_REGEXP_CODE(entry, p0, p1, p2, p3, p4, p5, p6) \
+  entry(p0, p1, p2, p3, p4, p5, p6)
+
+#define TRY_CATCH_FROM_ADDRESS(try_catch_address) \
+  reinterpret_cast<TryCatch*>(try_catch_address)
+
+
+#else   // #if defined(__mips)
+
+// When running with the simulator transition into simulated execution at this
+// point.
+#define CALL_GENERATED_CODE(entry, p0, p1, p2, p3, p4) \
+  reinterpret_cast<Object*>(\
+      assembler::mips::Simulator::current()->Call(FUNCTION_ADDR(entry), 5, \
+                                                  p0, p1, p2, p3, p4))
+
+#define CALL_GENERATED_REGEXP_CODE(entry, p0, p1, p2, p3, p4, p5, p6) \
+  assembler::mips::Simulator::current()->Call(\
+    FUNCTION_ADDR(entry), 7, p0, p1, p2, p3, p4, p5, p6)
+
+#define TRY_CATCH_FROM_ADDRESS(try_catch_address) \
+  try_catch_address == NULL ? \
+      NULL : *(reinterpret_cast<TryCatch**>(try_catch_address))
+
+
+namespace assembler {
+namespace mips {
+
+class Simulator {
+ public:
+  friend class Debugger;
+
+  // Registers are declared in order. See SMRL chapter 2.
+  enum Register {
+    no_reg = -1,
+    zero_reg = 0,
+    at,
+    v0, v1,
+    a0, a1, a2, a3,
+    t0, t1, t2, t3, t4, t5, t6, t7,
+    s0, s1, s2, s3, s4, s5, s6, s7,
+    t8, t9,
+    k0, k1,
+    gp,
+    sp,
+    s8,
+    ra,
+    // LO, HI, and pc
+    LO,
+    HI,
+    pc,   // pc must be the last register.
+    kNumSimuRegisters,
+    // aliases
+    fp = s8
+  };
+
+  // Coprocessor registers.
+  // Generated code will always use doubles. So we will only use even registers.
+  enum FPURegister {
+    f0, f1, f2, f3, f4, f5, f6, f7, f8, f9, f10, f11,
+    f12, f13, f14, f15,   // f12 and f14 are arguments FPURegisters
+    f16, f17, f18, f19, f20, f21, f22, f23, f24, f25,
+    f26, f27, f28, f29, f30, f31,
+    kNumFPURegisters
+  };
+
+  Simulator();
+  ~Simulator();
+
+  // The currently executing Simulator instance. Potentially there can be one
+  // for each native thread.
+  static Simulator* current();
+
+  // Accessors for register state. Reading the pc value adheres to the MIPS
+  // architecture specification and is off by a 8 from the currently executing
+  // instruction.
+  void set_register(int reg, int32_t value);
+  int32_t get_register(int reg) const;
+  // Same for FPURegisters
+  void set_fpu_register(int fpureg, int32_t value);
+  void set_fpu_register_double(int fpureg, double value);
+  int32_t get_fpu_register(int fpureg) const;
+  double get_fpu_register_double(int fpureg) const;
+
+  // Special case of set_register and get_register to access the raw PC value.
+  void set_pc(int32_t value);
+  int32_t get_pc() const;
+
+  // Accessor to the internal simulator stack area.
+  uintptr_t StackLimit() const;
+
+  // Executes MIPS instructions until the PC reaches end_sim_pc.
+  void Execute();
+
+  // Call on program start.
+  static void Initialize();
+
+  // V8 generally calls into generated JS code with 5 parameters and into
+  // generated RegExp code with 7 parameters. This is a convenience function,
+  // which sets up the simulator state and grabs the result on return.
+  int32_t Call(byte_* entry, int argument_count, ...);
+
+  // Push an address onto the JS stack.
+  uintptr_t PushAddress(uintptr_t address);
+
+  // Pop an address from the JS stack.
+  uintptr_t PopAddress();
+
+ private:
+  enum special_values {
+    // Known bad pc value to ensure that the simulator does not execute
+    // without being properly setup.
+    bad_ra = -1,
+    // A pc value used to signal the simulator to stop execution.  Generally
+    // the ra is set to this value on transition from native C code to
+    // simulated execution, so that the simulator can "return" to the native
+    // C code.
+    end_sim_pc = -2,
+    // Unpredictable value.
+    Unpredictable = 0xbadbeaf
+  };
+
+  // Unsupported instructions use Format to print an error and stop execution.
+  void Format(Instruction* instr, const char* format);
+
+  // Read and write memory.
+  inline uint32_t ReadBU(int32_t addr);
+  inline int32_t ReadB(int32_t addr);
+  inline void WriteB(int32_t addr, uint8_t value);
+  inline void WriteB(int32_t addr, int8_t value);
+
+  inline uint16_t ReadHU(int32_t addr, Instruction* instr);
+  inline int16_t ReadH(int32_t addr, Instruction* instr);
+  // Note: Overloaded on the sign of the value.
+  inline void WriteH(int32_t addr, uint16_t value, Instruction* instr);
+  inline void WriteH(int32_t addr, int16_t value, Instruction* instr);
+
+  inline int ReadW(int32_t addr, Instruction* instr);
+  inline void WriteW(int32_t addr, int value, Instruction* instr);
+
+  inline double ReadD(int32_t addr, Instruction* instr);
+  inline void WriteD(int32_t addr, double value, Instruction* instr);
+
+  // Operations depending on endianness.
+  // Get Double Higher / Lower word.
+  inline int32_t GetDoubleHIW(double* addr);
+  inline int32_t GetDoubleLOW(double* addr);
+  // Set Double Higher / Lower word.
+  inline int32_t SetDoubleHIW(double* addr);
+  inline int32_t SetDoubleLOW(double* addr);
+
+
+  // Executing is handled based on the instruction type.
+  void DecodeTypeRegister(Instruction* instr);
+  void DecodeTypeImmediate(Instruction* instr);
+  void DecodeTypeJump(Instruction* instr);
+
+  // Used for breakpoints and traps.
+  void SoftwareInterrupt(Instruction* instr);
+
+  // Executes one instruction.
+  void InstructionDecode(Instruction* instr);
+  // Execute one instruction placed in a branch delay slot.
+  void BranchDelayInstructionDecode(Instruction* instr) {
+    if (instr->IsForbiddenInBranchDelay()) {
+      V8_Fatal(__FILE__, __LINE__,
+               "Eror:Unexpected %i opcode in a branch delay slot.",
+               instr->OpcodeField());
+    }
+    InstructionDecode(instr);
+  }
+
+  enum Exception {
+    none,
+    kIntegerOverflow,
+    kIntegerUnderflow,
+    kDivideByZero,
+    kNumExceptions
+  };
+  int16_t exceptions[kNumExceptions];
+
+  // Exceptions.
+  void SignalExceptions();
+
+  // Runtime call support.
+  static void* RedirectExternalReference(void* external_function,
+                                         bool fp_return);
+
+  // Used for real time calls that takes two double values as arguments and
+  // returns a double.
+  void SetFpResult(double result);
+
+  // Architecture state.
+  // Registers.
+  int32_t registers_[kNumSimuRegisters];
+  // Coprocessor Registers.
+  int32_t FPUregisters_[kNumFPURegisters];
+
+  // Simulator support.
+  char* stack_;
+  bool pc_modified_;
+  int icount_;
+  static bool initialized_;
+
+  // Registered breakpoints.
+  Instruction* break_pc_;
+  Instr break_instr_;
+};
+
+} }   // namespace assembler::mips
+
+
+// The simulator has its own stack. Thus it has a different stack limit from
+// the C-based native code.  Setting the c_limit to indicate a very small
+// stack cause stack overflow errors, since the simulator ignores the input.
+// This is unlikely to be an issue in practice, though it might cause testing
+// trouble down the line.
+class SimulatorStack : public v8::internal::AllStatic {
+ public:
+  static inline uintptr_t JsLimitFromCLimit(uintptr_t c_limit) {
+    return assembler::mips::Simulator::current()->StackLimit();
+  }
+
+  static inline uintptr_t RegisterCTryCatch(uintptr_t try_catch_address) {
+    assembler::mips::Simulator* sim = assembler::mips::Simulator::current();
+    return sim->PushAddress(try_catch_address);
+  }
+
+  static inline void UnregisterCTryCatch() {
+    assembler::mips::Simulator::current()->PopAddress();
+  }
+};
+
+#endif  // defined(__mips)
+
+#endif  // V8_MIPS_SIMULATOR_MIPS_H_
+