| // Copyright 2008 Google Inc. 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 |
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| // 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 ARM instructions if we are not generating a native |
| // ARM binary. This Simulator allows us to run and debug ARM 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 ARM HW platform. |
| |
| #ifndef V8_SIMULATOR_ARM_H_ |
| #define V8_SIMULATOR_ARM_H_ |
| |
| #if defined(__arm__) |
| |
| // 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) |
| |
| // 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. |
| #define GENERATED_CODE_STACK_LIMIT(limit) \ |
| (reinterpret_cast<uintptr_t>(this) - limit) |
| |
| #else // defined(__arm__) |
| |
| // When running with the simulator transition into simulated execution at this |
| // point. |
| #define CALL_GENERATED_CODE(entry, p0, p1, p2, p3, p4) \ |
| assembler::arm::Simulator::current()->call((int32_t)entry, (int32_t)p0, \ |
| (int32_t)p1, (int32_t)p2, (int32_t)p3, (int32_t)p4) |
| |
| // The simulator has its own stack. Thus it has a different stack limit from |
| // the C-based native code. |
| #define GENERATED_CODE_STACK_LIMIT(limit) \ |
| (assembler::arm::Simulator::current()->StackLimit()) |
| |
| |
| #include "constants-arm.h" |
| |
| |
| namespace assembler { namespace arm { |
| |
| class Simulator { |
| public: |
| friend class Debugger; |
| |
| enum Register { |
| no_reg = -1, |
| r0 = 0, r1, r2, r3, r4, r5, r6, r7, |
| r8, r9, r10, r11, r12, r13, r14, r15, |
| num_registers, |
| sp = 13, |
| lr = 14, |
| pc = 15 |
| }; |
| |
| 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 ARM |
| // 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; |
| |
| // 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 ARM instructions until the PC reaches end_sim_pc. |
| void execute(); |
| |
| // V8 generally calls into generated code with 5 parameters. This is a |
| // convenience funtion, which sets up the simulator state and grabs the |
| // result on return. |
| v8::internal::Object* call(int32_t entry, int32_t p0, int32_t p1, |
| int32_t p2, int32_t p3, int32_t p4); |
| |
| private: |
| enum special_values { |
| // Known bad pc value to ensure that the simulator does not execute |
| // without being properly setup. |
| bad_lr = -1, |
| // A pc value used to signal the simulator to stop execution. Generally |
| // the lr 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 |
| }; |
| |
| // Unsupported instructions use Format to print an error and stop execution. |
| void Format(Instr* instr, const char* format); |
| |
| // Checks if the current instruction should be executed based on its |
| // condition bits. |
| bool ConditionallyExecute(Instr* instr); |
| |
| // Helper functions to set the conditional flags in the architecture state. |
| void SetNZFlags(int32_t val); |
| void SetCFlag(bool val); |
| void SetVFlag(bool val); |
| bool CarryFrom(int32_t left, int32_t right); |
| bool BorrowFrom(int32_t left, int32_t right); |
| bool OverflowFrom(int32_t alu_out, |
| int32_t left, |
| int32_t right, |
| bool addition); |
| |
| // Helper functions to decode common "addressing" modes |
| int32_t GetShiftRm(Instr* instr, bool* carry_out); |
| int32_t GetImm(Instr* instr, bool* carry_out); |
| void HandleRList(Instr* instr, bool load); |
| void SoftwareInterrupt(Instr* instr); |
| |
| // Executing is handled based on the instruction type. |
| void DecodeType01(Instr* instr); // both type 0 and type 1 rolled into one |
| void DecodeType2(Instr* instr); |
| void DecodeType3(Instr* instr); |
| void DecodeType4(Instr* instr); |
| void DecodeType5(Instr* instr); |
| void DecodeType6(Instr* instr); |
| void DecodeType7(Instr* instr); |
| |
| // Executes one instruction. |
| void InstructionDecode(Instr* instr); |
| |
| // architecture state |
| int32_t registers_[16]; |
| bool n_flag_; |
| bool z_flag_; |
| bool c_flag_; |
| bool v_flag_; |
| |
| // simulator support |
| char* stack_; |
| bool pc_modified_; |
| int icount_; |
| |
| // registered breakpoints |
| Instr* break_pc_; |
| instr_t break_instr_; |
| }; |
| |
| } } // namespace assembler::arm |
| |
| #endif // defined(__arm__) |
| |
| #endif // V8_SIMULATOR_ARM_H_ |