Update to V8 with partial snapshots. This is taken from the partial_snapshot branch of V8.
diff --git a/src/mips/simulator-mips.cc b/src/mips/simulator-mips.cc
new file mode 100644
index 0000000..2e2dc86
--- /dev/null
+++ b/src/mips/simulator-mips.cc
@@ -0,0 +1,1648 @@
+// 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.
+
+#include <stdlib.h>
+#include <cstdarg>
+#include "v8.h"
+
+#include "disasm.h"
+#include "assembler.h"
+#include "globals.h" // Need the bit_cast
+#include "mips/constants-mips.h"
+#include "mips/simulator-mips.h"
+
+namespace v8i = v8::internal;
+
+#if !defined(__mips)
+
+// Only build the simulator if not compiling for real MIPS hardware.
+namespace assembler {
+namespace mips {
+
+using ::v8::internal::Object;
+using ::v8::internal::PrintF;
+using ::v8::internal::OS;
+using ::v8::internal::ReadLine;
+using ::v8::internal::DeleteArray;
+
+// Utils functions
+bool HaveSameSign(int32_t a, int32_t b) {
+ return ((a ^ b) > 0);
+}
+
+
+// This macro provides a platform independent use of sscanf. The reason for
+// SScanF not being implemented in a platform independent was through
+// ::v8::internal::OS in the same way as SNPrintF is that the Windows C Run-Time
+// Library does not provide vsscanf.
+#define SScanF sscanf // NOLINT
+
+// The Debugger class is used by the simulator while debugging simulated MIPS
+// code.
+class Debugger {
+ public:
+ explicit Debugger(Simulator* sim);
+ ~Debugger();
+
+ void Stop(Instruction* instr);
+ void Debug();
+
+ private:
+ // We set the breakpoint code to 0xfffff to easily recognize it.
+ static const Instr kBreakpointInstr = SPECIAL | BREAK | 0xfffff << 6;
+ static const Instr kNopInstr = 0x0;
+
+ Simulator* sim_;
+
+ int32_t GetRegisterValue(int regnum);
+ bool GetValue(const char* desc, int32_t* value);
+
+ // Set or delete a breakpoint. Returns true if successful.
+ bool SetBreakpoint(Instruction* breakpc);
+ bool DeleteBreakpoint(Instruction* 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();
+
+ // Print all registers with a nice formatting.
+ void PrintAllRegs();
+};
+
+Debugger::Debugger(Simulator* sim) {
+ sim_ = sim;
+}
+
+Debugger::~Debugger() {
+}
+
+#ifdef GENERATED_CODE_COVERAGE
+static FILE* coverage_log = NULL;
+
+
+static void InitializeCoverage() {
+ char* file_name = getenv("V8_GENERATED_CODE_COVERAGE_LOG");
+ if (file_name != NULL) {
+ coverage_log = fopen(file_name, "aw+");
+ }
+}
+
+
+void Debugger::Stop(Instruction* instr) {
+ UNIMPLEMENTED_MIPS();
+ char* str = reinterpret_cast<char*>(instr->InstructionBits());
+ if (strlen(str) > 0) {
+ if (coverage_log != NULL) {
+ fprintf(coverage_log, "%s\n", str);
+ fflush(coverage_log);
+ }
+ instr->SetInstructionBits(0x0); // Overwrite with nop.
+ }
+ sim_->set_pc(sim_->get_pc() + Instruction::kInstructionSize);
+}
+
+#else // ndef GENERATED_CODE_COVERAGE
+
+#define UNSUPPORTED() printf("Unsupported instruction.\n");
+
+static void InitializeCoverage() {}
+
+
+void Debugger::Stop(Instruction* instr) {
+ const char* str = reinterpret_cast<char*>(instr->InstructionBits());
+ PrintF("Simulator hit %s\n", str);
+ sim_->set_pc(sim_->get_pc() + Instruction::kInstructionSize);
+ Debug();
+}
+#endif // def GENERATED_CODE_COVERAGE
+
+
+int32_t Debugger::GetRegisterValue(int regnum) {
+ if (regnum == kNumSimuRegisters) {
+ return sim_->get_pc();
+ } else {
+ return sim_->get_register(regnum);
+ }
+}
+
+
+bool Debugger::GetValue(const char* desc, int32_t* value) {
+ int regnum = Registers::Number(desc);
+ if (regnum != kInvalidRegister) {
+ *value = GetRegisterValue(regnum);
+ return true;
+ } else {
+ return SScanF(desc, "%i", value) == 1;
+ }
+ return false;
+}
+
+
+bool Debugger::SetBreakpoint(Instruction* breakpc) {
+ // Check if a breakpoint can be set. If not return without any side-effects.
+ if (sim_->break_pc_ != NULL) {
+ return false;
+ }
+
+ // Set the breakpoint.
+ sim_->break_pc_ = breakpc;
+ sim_->break_instr_ = breakpc->InstructionBits();
+ // Not setting the breakpoint instruction in the code itself. It will be set
+ // when the debugger shell continues.
+ return true;
+}
+
+
+bool Debugger::DeleteBreakpoint(Instruction* breakpc) {
+ if (sim_->break_pc_ != NULL) {
+ sim_->break_pc_->SetInstructionBits(sim_->break_instr_);
+ }
+
+ sim_->break_pc_ = NULL;
+ sim_->break_instr_ = 0;
+ return true;
+}
+
+
+void Debugger::UndoBreakpoints() {
+ if (sim_->break_pc_ != NULL) {
+ sim_->break_pc_->SetInstructionBits(sim_->break_instr_);
+ }
+}
+
+
+void Debugger::RedoBreakpoints() {
+ if (sim_->break_pc_ != NULL) {
+ sim_->break_pc_->SetInstructionBits(kBreakpointInstr);
+ }
+}
+
+void Debugger::PrintAllRegs() {
+#define REG_INFO(n) Registers::Name(n), GetRegisterValue(n), GetRegisterValue(n)
+
+ PrintF("\n");
+ // at, v0, a0
+ PrintF("%3s: 0x%08x %10d\t%3s: 0x%08x %10d\t%3s: 0x%08x %10d\n",
+ REG_INFO(1), REG_INFO(2), REG_INFO(4));
+ // v1, a1
+ PrintF("%26s\t%3s: 0x%08x %10d\t%3s: 0x%08x %10d\n",
+ "", REG_INFO(3), REG_INFO(5));
+ // a2
+ PrintF("%26s\t%26s\t%3s: 0x%08x %10d\n", "", "", REG_INFO(6));
+ // a3
+ PrintF("%26s\t%26s\t%3s: 0x%08x %10d\n", "", "", REG_INFO(7));
+ PrintF("\n");
+ // t0-t7, s0-s7
+ for (int i = 0; i < 8; i++) {
+ PrintF("%3s: 0x%08x %10d\t%3s: 0x%08x %10d\n",
+ REG_INFO(8+i), REG_INFO(16+i));
+ }
+ PrintF("\n");
+ // t8, k0, LO
+ PrintF("%3s: 0x%08x %10d\t%3s: 0x%08x %10d\t%3s: 0x%08x %10d\n",
+ REG_INFO(24), REG_INFO(26), REG_INFO(32));
+ // t9, k1, HI
+ PrintF("%3s: 0x%08x %10d\t%3s: 0x%08x %10d\t%3s: 0x%08x %10d\n",
+ REG_INFO(25), REG_INFO(27), REG_INFO(33));
+ // sp, fp, gp
+ PrintF("%3s: 0x%08x %10d\t%3s: 0x%08x %10d\t%3s: 0x%08x %10d\n",
+ REG_INFO(29), REG_INFO(30), REG_INFO(28));
+ // pc
+ PrintF("%3s: 0x%08x %10d\t%3s: 0x%08x %10d\n",
+ REG_INFO(31), REG_INFO(34));
+#undef REG_INFO
+}
+
+void Debugger::Debug() {
+ intptr_t last_pc = -1;
+ bool done = false;
+
+#define COMMAND_SIZE 63
+#define ARG_SIZE 255
+
+#define STR(a) #a
+#define XSTR(a) STR(a)
+
+ char cmd[COMMAND_SIZE + 1];
+ char arg1[ARG_SIZE + 1];
+ char arg2[ARG_SIZE + 1];
+
+ // make sure to have a proper terminating character if reaching the limit
+ cmd[COMMAND_SIZE] = 0;
+ arg1[ARG_SIZE] = 0;
+ arg2[ARG_SIZE] = 0;
+
+ // Undo all set breakpoints while running in the debugger shell. This will
+ // make them invisible to all commands.
+ UndoBreakpoints();
+
+ while (!done && (sim_->get_pc() != Simulator::end_sim_pc)) {
+ if (last_pc != sim_->get_pc()) {
+ disasm::NameConverter converter;
+ disasm::Disassembler dasm(converter);
+ // use a reasonably large buffer
+ v8::internal::EmbeddedVector<char, 256> buffer;
+ dasm.InstructionDecode(buffer,
+ reinterpret_cast<byte_*>(sim_->get_pc()));
+ PrintF(" 0x%08x %s\n", sim_->get_pc(), buffer.start());
+ last_pc = sim_->get_pc();
+ }
+ char* line = ReadLine("sim> ");
+ if (line == NULL) {
+ break;
+ } else {
+ // Use sscanf to parse the individual parts of the command line. At the
+ // moment no command expects more than two parameters.
+ int args = SScanF(line,
+ "%" XSTR(COMMAND_SIZE) "s "
+ "%" XSTR(ARG_SIZE) "s "
+ "%" XSTR(ARG_SIZE) "s",
+ cmd, arg1, arg2);
+ if ((strcmp(cmd, "si") == 0) || (strcmp(cmd, "stepi") == 0)) {
+ if (!(reinterpret_cast<Instruction*>(sim_->get_pc())->IsTrap())) {
+ sim_->InstructionDecode(
+ reinterpret_cast<Instruction*>(sim_->get_pc()));
+ } else {
+ // Allow si to jump over generated breakpoints.
+ PrintF("/!\\ Jumping over generated breakpoint.\n");
+ sim_->set_pc(sim_->get_pc() + Instruction::kInstructionSize);
+ }
+ } else if ((strcmp(cmd, "c") == 0) || (strcmp(cmd, "cont") == 0)) {
+ // Execute the one instruction we broke at with breakpoints disabled.
+ sim_->InstructionDecode(reinterpret_cast<Instruction*>(sim_->get_pc()));
+ // Leave the debugger shell.
+ done = true;
+ } else if ((strcmp(cmd, "p") == 0) || (strcmp(cmd, "print") == 0)) {
+ if (args == 2) {
+ int32_t value;
+ if (strcmp(arg1, "all") == 0) {
+ PrintAllRegs();
+ } else {
+ if (GetValue(arg1, &value)) {
+ PrintF("%s: 0x%08x %d \n", arg1, value, value);
+ } else {
+ PrintF("%s unrecognized\n", arg1);
+ }
+ }
+ } else {
+ PrintF("print <register>\n");
+ }
+ } else if ((strcmp(cmd, "po") == 0)
+ || (strcmp(cmd, "printobject") == 0)) {
+ if (args == 2) {
+ int32_t value;
+ if (GetValue(arg1, &value)) {
+ Object* obj = reinterpret_cast<Object*>(value);
+ PrintF("%s: \n", arg1);
+#ifdef DEBUG
+ obj->PrintLn();
+#else
+ obj->ShortPrint();
+ PrintF("\n");
+#endif
+ } else {
+ PrintF("%s unrecognized\n", arg1);
+ }
+ } else {
+ PrintF("printobject <value>\n");
+ }
+ } else if ((strcmp(cmd, "disasm") == 0) || (strcmp(cmd, "dpc") == 0)) {
+ disasm::NameConverter converter;
+ disasm::Disassembler dasm(converter);
+ // use a reasonably large buffer
+ v8::internal::EmbeddedVector<char, 256> buffer;
+
+ byte_* cur = NULL;
+ byte_* end = NULL;
+
+ if (args == 1) {
+ cur = reinterpret_cast<byte_*>(sim_->get_pc());
+ end = cur + (10 * Instruction::kInstructionSize);
+ } else if (args == 2) {
+ int32_t value;
+ if (GetValue(arg1, &value)) {
+ cur = reinterpret_cast<byte_*>(value);
+ // no length parameter passed, assume 10 instructions
+ end = cur + (10 * Instruction::kInstructionSize);
+ }
+ } else {
+ int32_t value1;
+ int32_t value2;
+ if (GetValue(arg1, &value1) && GetValue(arg2, &value2)) {
+ cur = reinterpret_cast<byte_*>(value1);
+ end = cur + (value2 * Instruction::kInstructionSize);
+ }
+ }
+
+ while (cur < end) {
+ dasm.InstructionDecode(buffer, cur);
+ PrintF(" 0x%08x %s\n", cur, buffer.start());
+ cur += Instruction::kInstructionSize;
+ }
+ } else if (strcmp(cmd, "gdb") == 0) {
+ PrintF("relinquishing control to gdb\n");
+ v8::internal::OS::DebugBreak();
+ PrintF("regaining control from gdb\n");
+ } else if (strcmp(cmd, "break") == 0) {
+ if (args == 2) {
+ int32_t value;
+ if (GetValue(arg1, &value)) {
+ if (!SetBreakpoint(reinterpret_cast<Instruction*>(value))) {
+ PrintF("setting breakpoint failed\n");
+ }
+ } else {
+ PrintF("%s unrecognized\n", arg1);
+ }
+ } else {
+ PrintF("break <address>\n");
+ }
+ } else if (strcmp(cmd, "del") == 0) {
+ if (!DeleteBreakpoint(NULL)) {
+ PrintF("deleting breakpoint failed\n");
+ }
+ } else if (strcmp(cmd, "flags") == 0) {
+ PrintF("No flags on MIPS !\n");
+ } else if (strcmp(cmd, "unstop") == 0) {
+ PrintF("Unstop command not implemented on MIPS.");
+ } else if ((strcmp(cmd, "stat") == 0) || (strcmp(cmd, "st") == 0)) {
+ // Print registers and disassemble
+ PrintAllRegs();
+ PrintF("\n");
+
+ disasm::NameConverter converter;
+ disasm::Disassembler dasm(converter);
+ // use a reasonably large buffer
+ v8::internal::EmbeddedVector<char, 256> buffer;
+
+ byte_* cur = NULL;
+ byte_* end = NULL;
+
+ if (args == 1) {
+ cur = reinterpret_cast<byte_*>(sim_->get_pc());
+ end = cur + (10 * Instruction::kInstructionSize);
+ } else if (args == 2) {
+ int32_t value;
+ if (GetValue(arg1, &value)) {
+ cur = reinterpret_cast<byte_*>(value);
+ // no length parameter passed, assume 10 instructions
+ end = cur + (10 * Instruction::kInstructionSize);
+ }
+ } else {
+ int32_t value1;
+ int32_t value2;
+ if (GetValue(arg1, &value1) && GetValue(arg2, &value2)) {
+ cur = reinterpret_cast<byte_*>(value1);
+ end = cur + (value2 * Instruction::kInstructionSize);
+ }
+ }
+
+ while (cur < end) {
+ dasm.InstructionDecode(buffer, cur);
+ PrintF(" 0x%08x %s\n", cur, buffer.start());
+ cur += Instruction::kInstructionSize;
+ }
+ } else if ((strcmp(cmd, "h") == 0) || (strcmp(cmd, "help") == 0)) {
+ PrintF("cont\n");
+ PrintF(" continue execution (alias 'c')\n");
+ PrintF("stepi\n");
+ PrintF(" step one instruction (alias 'si')\n");
+ PrintF("print <register>\n");
+ PrintF(" print register content (alias 'p')\n");
+ PrintF(" use register name 'all' to print all registers\n");
+ PrintF("printobject <register>\n");
+ PrintF(" print an object from a register (alias 'po')\n");
+ PrintF("flags\n");
+ PrintF(" print flags\n");
+ PrintF("disasm [<instructions>]\n");
+ PrintF("disasm [[<address>] <instructions>]\n");
+ PrintF(" disassemble code, default is 10 instructions from pc\n");
+ PrintF("gdb\n");
+ PrintF(" enter gdb\n");
+ PrintF("break <address>\n");
+ PrintF(" set a break point on the address\n");
+ PrintF("del\n");
+ PrintF(" delete the breakpoint\n");
+ PrintF("unstop\n");
+ PrintF(" ignore the stop instruction at the current location");
+ PrintF(" from now on\n");
+ } else {
+ PrintF("Unknown command: %s\n", cmd);
+ }
+ }
+ DeleteArray(line);
+ }
+
+ // Add all the breakpoints back to stop execution and enter the debugger
+ // shell when hit.
+ RedoBreakpoints();
+
+#undef COMMAND_SIZE
+#undef ARG_SIZE
+
+#undef STR
+#undef XSTR
+}
+
+
+// Create one simulator per thread and keep it in thread local storage.
+static v8::internal::Thread::LocalStorageKey simulator_key;
+
+
+bool Simulator::initialized_ = false;
+
+
+void Simulator::Initialize() {
+ if (initialized_) return;
+ simulator_key = v8::internal::Thread::CreateThreadLocalKey();
+ initialized_ = true;
+ ::v8::internal::ExternalReference::set_redirector(&RedirectExternalReference);
+}
+
+
+Simulator::Simulator() {
+ Initialize();
+ // Setup simulator support first. Some of this information is needed to
+ // setup the architecture state.
+ size_t stack_size = 1 * 1024*1024; // allocate 1MB for stack
+ stack_ = reinterpret_cast<char*>(malloc(stack_size));
+ pc_modified_ = false;
+ icount_ = 0;
+ break_pc_ = NULL;
+ break_instr_ = 0;
+
+ // Setup architecture state.
+ // All registers are initialized to zero to start with.
+ for (int i = 0; i < kNumSimuRegisters; i++) {
+ registers_[i] = 0;
+ }
+
+ // The sp is initialized to point to the bottom (high address) of the
+ // allocated stack area. To be safe in potential stack underflows we leave
+ // some buffer below.
+ registers_[sp] = reinterpret_cast<int32_t>(stack_) + stack_size - 64;
+ // The ra and pc are initialized to a known bad value that will cause an
+ // access violation if the simulator ever tries to execute it.
+ registers_[pc] = bad_ra;
+ registers_[ra] = bad_ra;
+ InitializeCoverage();
+}
+
+
+// When the generated code calls an external reference we need to catch that in
+// the simulator. The external reference will be a function compiled for the
+// host architecture. We need to call that function instead of trying to
+// execute it with the simulator. We do that by redirecting the external
+// reference to a swi (software-interrupt) instruction that is handled by
+// the simulator. We write the original destination of the jump just at a known
+// offset from the swi instruction so the simulator knows what to call.
+class Redirection {
+ public:
+ Redirection(void* external_function, bool fp_return)
+ : external_function_(external_function),
+ swi_instruction_(rtCallRedirInstr),
+ fp_return_(fp_return),
+ next_(list_) {
+ list_ = this;
+ }
+
+ void* address_of_swi_instruction() {
+ return reinterpret_cast<void*>(&swi_instruction_);
+ }
+
+ void* external_function() { return external_function_; }
+ bool fp_return() { return fp_return_; }
+
+ static Redirection* Get(void* external_function, bool fp_return) {
+ Redirection* current;
+ for (current = list_; current != NULL; current = current->next_) {
+ if (current->external_function_ == external_function) return current;
+ }
+ return new Redirection(external_function, fp_return);
+ }
+
+ static Redirection* FromSwiInstruction(Instruction* swi_instruction) {
+ char* addr_of_swi = reinterpret_cast<char*>(swi_instruction);
+ char* addr_of_redirection =
+ addr_of_swi - OFFSET_OF(Redirection, swi_instruction_);
+ return reinterpret_cast<Redirection*>(addr_of_redirection);
+ }
+
+ private:
+ void* external_function_;
+ uint32_t swi_instruction_;
+ bool fp_return_;
+ Redirection* next_;
+ static Redirection* list_;
+};
+
+
+Redirection* Redirection::list_ = NULL;
+
+
+void* Simulator::RedirectExternalReference(void* external_function,
+ bool fp_return) {
+ Redirection* redirection = Redirection::Get(external_function, fp_return);
+ return redirection->address_of_swi_instruction();
+}
+
+
+// Get the active Simulator for the current thread.
+Simulator* Simulator::current() {
+ Initialize();
+ Simulator* sim = reinterpret_cast<Simulator*>(
+ v8::internal::Thread::GetThreadLocal(simulator_key));
+ if (sim == NULL) {
+ // TODO(146): delete the simulator object when a thread goes away.
+ sim = new Simulator();
+ v8::internal::Thread::SetThreadLocal(simulator_key, sim);
+ }
+ return sim;
+}
+
+
+// Sets the register in the architecture state. It will also deal with updating
+// Simulator internal state for special registers such as PC.
+void Simulator::set_register(int reg, int32_t value) {
+ ASSERT((reg >= 0) && (reg < kNumSimuRegisters));
+ if (reg == pc) {
+ pc_modified_ = true;
+ }
+
+ // zero register always hold 0.
+ registers_[reg] = (reg == 0) ? 0 : value;
+}
+
+void Simulator::set_fpu_register(int fpureg, int32_t value) {
+ ASSERT((fpureg >= 0) && (fpureg < kNumFPURegisters));
+ FPUregisters_[fpureg] = value;
+}
+
+void Simulator::set_fpu_register_double(int fpureg, double value) {
+ ASSERT((fpureg >= 0) && (fpureg < kNumFPURegisters) && ((fpureg % 2) == 0));
+ *v8i::bit_cast<double*, int32_t*>(&FPUregisters_[fpureg]) = value;
+}
+
+
+// Get the register from the architecture state. This function does handle
+// the special case of accessing the PC register.
+int32_t Simulator::get_register(int reg) const {
+ ASSERT((reg >= 0) && (reg < kNumSimuRegisters));
+ if (reg == 0)
+ return 0;
+ else
+ return registers_[reg] + ((reg == pc) ? Instruction::kPCReadOffset : 0);
+}
+
+int32_t Simulator::get_fpu_register(int fpureg) const {
+ ASSERT((fpureg >= 0) && (fpureg < kNumFPURegisters));
+ return FPUregisters_[fpureg];
+}
+
+double Simulator::get_fpu_register_double(int fpureg) const {
+ ASSERT((fpureg >= 0) && (fpureg < kNumFPURegisters) && ((fpureg % 2) == 0));
+ return *v8i::bit_cast<double*, int32_t*>(
+ const_cast<int32_t*>(&FPUregisters_[fpureg]));
+}
+
+// Raw access to the PC register.
+void Simulator::set_pc(int32_t value) {
+ pc_modified_ = true;
+ registers_[pc] = value;
+}
+
+// Raw access to the PC register without the special adjustment when reading.
+int32_t Simulator::get_pc() const {
+ return registers_[pc];
+}
+
+
+// The MIPS cannot do unaligned reads and writes. On some MIPS platforms an
+// interrupt is caused. On others it does a funky rotation thing. For now we
+// simply disallow unaligned reads, but at some point we may want to move to
+// emulating the rotate behaviour. Note that simulator runs have the runtime
+// system running directly on the host system and only generated code is
+// executed in the simulator. Since the host is typically IA32 we will not
+// get the correct MIPS-like behaviour on unaligned accesses.
+
+int Simulator::ReadW(int32_t addr, Instruction* instr) {
+ if ((addr & v8i::kPointerAlignmentMask) == 0) {
+ intptr_t* ptr = reinterpret_cast<intptr_t*>(addr);
+ return *ptr;
+ }
+ PrintF("Unaligned read at 0x%08x, pc=%p\n", addr, instr);
+ OS::Abort();
+ return 0;
+}
+
+
+void Simulator::WriteW(int32_t addr, int value, Instruction* instr) {
+ if ((addr & v8i::kPointerAlignmentMask) == 0) {
+ intptr_t* ptr = reinterpret_cast<intptr_t*>(addr);
+ *ptr = value;
+ return;
+ }
+ PrintF("Unaligned write at 0x%08x, pc=%p\n", addr, instr);
+ OS::Abort();
+}
+
+
+double Simulator::ReadD(int32_t addr, Instruction* instr) {
+ if ((addr & kDoubleAlignmentMask) == 0) {
+ double* ptr = reinterpret_cast<double*>(addr);
+ return *ptr;
+ }
+ PrintF("Unaligned read at 0x%08x, pc=%p\n", addr, instr);
+ OS::Abort();
+ return 0;
+}
+
+
+void Simulator::WriteD(int32_t addr, double value, Instruction* instr) {
+ if ((addr & kDoubleAlignmentMask) == 0) {
+ double* ptr = reinterpret_cast<double*>(addr);
+ *ptr = value;
+ return;
+ }
+ PrintF("Unaligned write at 0x%08x, pc=%p\n", addr, instr);
+ OS::Abort();
+}
+
+
+uint16_t Simulator::ReadHU(int32_t addr, Instruction* instr) {
+ if ((addr & 1) == 0) {
+ uint16_t* ptr = reinterpret_cast<uint16_t*>(addr);
+ return *ptr;
+ }
+ PrintF("Unaligned unsigned halfword read at 0x%08x, pc=%p\n", addr, instr);
+ OS::Abort();
+ return 0;
+}
+
+
+int16_t Simulator::ReadH(int32_t addr, Instruction* instr) {
+ if ((addr & 1) == 0) {
+ int16_t* ptr = reinterpret_cast<int16_t*>(addr);
+ return *ptr;
+ }
+ PrintF("Unaligned signed halfword read at 0x%08x, pc=%p\n", addr, instr);
+ OS::Abort();
+ return 0;
+}
+
+
+void Simulator::WriteH(int32_t addr, uint16_t value, Instruction* instr) {
+ if ((addr & 1) == 0) {
+ uint16_t* ptr = reinterpret_cast<uint16_t*>(addr);
+ *ptr = value;
+ return;
+ }
+ PrintF("Unaligned unsigned halfword write at 0x%08x, pc=%p\n", addr, instr);
+ OS::Abort();
+}
+
+
+void Simulator::WriteH(int32_t addr, int16_t value, Instruction* instr) {
+ if ((addr & 1) == 0) {
+ int16_t* ptr = reinterpret_cast<int16_t*>(addr);
+ *ptr = value;
+ return;
+ }
+ PrintF("Unaligned halfword write at 0x%08x, pc=%p\n", addr, instr);
+ OS::Abort();
+}
+
+
+uint32_t Simulator::ReadBU(int32_t addr) {
+ uint8_t* ptr = reinterpret_cast<uint8_t*>(addr);
+ return *ptr & 0xff;
+}
+
+
+int32_t Simulator::ReadB(int32_t addr) {
+ int8_t* ptr = reinterpret_cast<int8_t*>(addr);
+ return ((*ptr << 24) >> 24) & 0xff;
+}
+
+
+void Simulator::WriteB(int32_t addr, uint8_t value) {
+ uint8_t* ptr = reinterpret_cast<uint8_t*>(addr);
+ *ptr = value;
+}
+
+
+void Simulator::WriteB(int32_t addr, int8_t value) {
+ int8_t* ptr = reinterpret_cast<int8_t*>(addr);
+ *ptr = value;
+}
+
+
+// Returns the limit of the stack area to enable checking for stack overflows.
+uintptr_t Simulator::StackLimit() const {
+ // Leave a safety margin of 256 bytes to prevent overrunning the stack when
+ // pushing values.
+ return reinterpret_cast<uintptr_t>(stack_) + 256;
+}
+
+
+// Unsupported instructions use Format to print an error and stop execution.
+void Simulator::Format(Instruction* instr, const char* format) {
+ PrintF("Simulator found unsupported instruction:\n 0x%08x: %s\n",
+ instr, format);
+ UNIMPLEMENTED_MIPS();
+}
+
+
+// Calls into the V8 runtime are based on this very simple interface.
+// Note: To be able to return two values from some calls the code in runtime.cc
+// uses the ObjectPair which is essentially two 32-bit values stuffed into a
+// 64-bit value. With the code below we assume that all runtime calls return
+// 64 bits of result. If they don't, the r1 result register contains a bogus
+// value, which is fine because it is caller-saved.
+typedef int64_t (*SimulatorRuntimeCall)(int32_t arg0,
+ int32_t arg1,
+ int32_t arg2,
+ int32_t arg3);
+typedef double (*SimulatorRuntimeFPCall)(double fparg0,
+ double fparg1);
+
+
+// Software interrupt instructions are used by the simulator to call into the
+// C-based V8 runtime.
+void Simulator::SoftwareInterrupt(Instruction* instr) {
+ // We first check if we met a call_rt_redirected.
+ if (instr->InstructionBits() == rtCallRedirInstr) {
+ Redirection* redirection = Redirection::FromSwiInstruction(instr);
+ int32_t arg0 = get_register(a0);
+ int32_t arg1 = get_register(a1);
+ int32_t arg2 = get_register(a2);
+ int32_t arg3 = get_register(a3);
+ // fp args are (not always) in f12 and f14.
+ // See MIPS conventions for more details.
+ double fparg0 = get_fpu_register_double(f12);
+ double fparg1 = get_fpu_register_double(f14);
+ // This is dodgy but it works because the C entry stubs are never moved.
+ // See comment in codegen-arm.cc and bug 1242173.
+ int32_t saved_ra = get_register(ra);
+ if (redirection->fp_return()) {
+ intptr_t external =
+ reinterpret_cast<intptr_t>(redirection->external_function());
+ SimulatorRuntimeFPCall target =
+ reinterpret_cast<SimulatorRuntimeFPCall>(external);
+ if (::v8::internal::FLAG_trace_sim) {
+ PrintF("Call to host function at %p with args %f, %f\n",
+ FUNCTION_ADDR(target), fparg0, fparg1);
+ }
+ double result = target(fparg0, fparg1);
+ set_fpu_register_double(f0, result);
+ } else {
+ intptr_t external =
+ reinterpret_cast<int32_t>(redirection->external_function());
+ SimulatorRuntimeCall target =
+ reinterpret_cast<SimulatorRuntimeCall>(external);
+ if (::v8::internal::FLAG_trace_sim) {
+ PrintF(
+ "Call to host function at %p with args %08x, %08x, %08x, %08x\n",
+ FUNCTION_ADDR(target),
+ arg0,
+ arg1,
+ arg2,
+ arg3);
+ }
+ int64_t result = target(arg0, arg1, arg2, arg3);
+ int32_t lo_res = static_cast<int32_t>(result);
+ int32_t hi_res = static_cast<int32_t>(result >> 32);
+ if (::v8::internal::FLAG_trace_sim) {
+ PrintF("Returned %08x\n", lo_res);
+ }
+ set_register(v0, lo_res);
+ set_register(v1, hi_res);
+ }
+ set_register(ra, saved_ra);
+ set_pc(get_register(ra));
+ } else {
+ Debugger dbg(this);
+ dbg.Debug();
+ }
+}
+
+void Simulator::SignalExceptions() {
+ for (int i = 1; i < kNumExceptions; i++) {
+ if (exceptions[i] != 0) {
+ V8_Fatal(__FILE__, __LINE__, "Error: Exception %i raised.", i);
+ }
+ }
+}
+
+// Handle execution based on instruction types.
+void Simulator::DecodeTypeRegister(Instruction* instr) {
+ // Instruction fields
+ Opcode op = instr->OpcodeFieldRaw();
+ int32_t rs_reg = instr->RsField();
+ int32_t rs = get_register(rs_reg);
+ uint32_t rs_u = static_cast<uint32_t>(rs);
+ int32_t rt_reg = instr->RtField();
+ int32_t rt = get_register(rt_reg);
+ uint32_t rt_u = static_cast<uint32_t>(rt);
+ int32_t rd_reg = instr->RdField();
+ uint32_t sa = instr->SaField();
+
+ int32_t fs_reg= instr->FsField();
+
+ // ALU output
+ // It should not be used as is. Instructions using it should always initialize
+ // it first.
+ int32_t alu_out = 0x12345678;
+ // Output or temporary for floating point.
+ double fp_out = 0.0;
+
+ // For break and trap instructions.
+ bool do_interrupt = false;
+
+ // For jr and jalr
+ // Get current pc.
+ int32_t current_pc = get_pc();
+ // Next pc
+ int32_t next_pc = 0;
+
+ // ---------- Configuration
+ switch (op) {
+ case COP1: // Coprocessor instructions
+ switch (instr->RsFieldRaw()) {
+ case BC1: // branch on coprocessor condition
+ UNREACHABLE();
+ break;
+ case MFC1:
+ alu_out = get_fpu_register(fs_reg);
+ break;
+ case MFHC1:
+ fp_out = get_fpu_register_double(fs_reg);
+ alu_out = *v8i::bit_cast<int32_t*, double*>(&fp_out);
+ break;
+ case MTC1:
+ case MTHC1:
+ // Do the store in the execution step.
+ break;
+ case S:
+ case D:
+ case W:
+ case L:
+ case PS:
+ // Do everything in the execution step.
+ break;
+ default:
+ UNIMPLEMENTED_MIPS();
+ };
+ break;
+ case SPECIAL:
+ switch (instr->FunctionFieldRaw()) {
+ case JR:
+ case JALR:
+ next_pc = get_register(instr->RsField());
+ break;
+ case SLL:
+ alu_out = rt << sa;
+ break;
+ case SRL:
+ alu_out = rt_u >> sa;
+ break;
+ case SRA:
+ alu_out = rt >> sa;
+ break;
+ case SLLV:
+ alu_out = rt << rs;
+ break;
+ case SRLV:
+ alu_out = rt_u >> rs;
+ break;
+ case SRAV:
+ alu_out = rt >> rs;
+ break;
+ case MFHI:
+ alu_out = get_register(HI);
+ break;
+ case MFLO:
+ alu_out = get_register(LO);
+ break;
+ case MULT:
+ UNIMPLEMENTED_MIPS();
+ break;
+ case MULTU:
+ UNIMPLEMENTED_MIPS();
+ break;
+ case DIV:
+ case DIVU:
+ exceptions[kDivideByZero] = rt == 0;
+ break;
+ case ADD:
+ if (HaveSameSign(rs, rt)) {
+ if (rs > 0) {
+ exceptions[kIntegerOverflow] = rs > (Registers::kMaxValue - rt);
+ } else if (rs < 0) {
+ exceptions[kIntegerUnderflow] = rs < (Registers::kMinValue - rt);
+ }
+ }
+ alu_out = rs + rt;
+ break;
+ case ADDU:
+ alu_out = rs + rt;
+ break;
+ case SUB:
+ if (!HaveSameSign(rs, rt)) {
+ if (rs > 0) {
+ exceptions[kIntegerOverflow] = rs > (Registers::kMaxValue + rt);
+ } else if (rs < 0) {
+ exceptions[kIntegerUnderflow] = rs < (Registers::kMinValue + rt);
+ }
+ }
+ alu_out = rs - rt;
+ break;
+ case SUBU:
+ alu_out = rs - rt;
+ break;
+ case AND:
+ alu_out = rs & rt;
+ break;
+ case OR:
+ alu_out = rs | rt;
+ break;
+ case XOR:
+ alu_out = rs ^ rt;
+ break;
+ case NOR:
+ alu_out = ~(rs | rt);
+ break;
+ case SLT:
+ alu_out = rs < rt ? 1 : 0;
+ break;
+ case SLTU:
+ alu_out = rs_u < rt_u ? 1 : 0;
+ break;
+ // Break and trap instructions
+ case BREAK:
+ do_interrupt = true;
+ break;
+ case TGE:
+ do_interrupt = rs >= rt;
+ break;
+ case TGEU:
+ do_interrupt = rs_u >= rt_u;
+ break;
+ case TLT:
+ do_interrupt = rs < rt;
+ break;
+ case TLTU:
+ do_interrupt = rs_u < rt_u;
+ break;
+ case TEQ:
+ do_interrupt = rs == rt;
+ break;
+ case TNE:
+ do_interrupt = rs != rt;
+ break;
+ default:
+ UNREACHABLE();
+ };
+ break;
+ case SPECIAL2:
+ switch (instr->FunctionFieldRaw()) {
+ case MUL:
+ alu_out = rs_u * rt_u; // Only the lower 32 bits are kept.
+ break;
+ default:
+ UNREACHABLE();
+ }
+ break;
+ default:
+ UNREACHABLE();
+ };
+
+ // ---------- Raise exceptions triggered.
+ SignalExceptions();
+
+ // ---------- Execution
+ switch (op) {
+ case COP1:
+ switch (instr->RsFieldRaw()) {
+ case BC1: // branch on coprocessor condition
+ UNREACHABLE();
+ break;
+ case MFC1:
+ case MFHC1:
+ set_register(rt_reg, alu_out);
+ break;
+ case MTC1:
+ // We don't need to set the higher bits to 0, because MIPS ISA says
+ // they are in an unpredictable state after executing MTC1.
+ FPUregisters_[fs_reg] = registers_[rt_reg];
+ FPUregisters_[fs_reg+1] = Unpredictable;
+ break;
+ case MTHC1:
+ // Here we need to keep the lower bits unchanged.
+ FPUregisters_[fs_reg+1] = registers_[rt_reg];
+ break;
+ case S:
+ switch (instr->FunctionFieldRaw()) {
+ case CVT_D_S:
+ case CVT_W_S:
+ case CVT_L_S:
+ case CVT_PS_S:
+ UNIMPLEMENTED_MIPS();
+ break;
+ default:
+ UNREACHABLE();
+ }
+ break;
+ case D:
+ switch (instr->FunctionFieldRaw()) {
+ case CVT_S_D:
+ case CVT_W_D:
+ case CVT_L_D:
+ UNIMPLEMENTED_MIPS();
+ break;
+ default:
+ UNREACHABLE();
+ }
+ break;
+ case W:
+ switch (instr->FunctionFieldRaw()) {
+ case CVT_S_W:
+ UNIMPLEMENTED_MIPS();
+ break;
+ case CVT_D_W: // Convert word to double.
+ set_fpu_register(rd_reg, static_cast<double>(rs));
+ break;
+ default:
+ UNREACHABLE();
+ };
+ break;
+ case L:
+ switch (instr->FunctionFieldRaw()) {
+ case CVT_S_L:
+ case CVT_D_L:
+ UNIMPLEMENTED_MIPS();
+ break;
+ default:
+ UNREACHABLE();
+ }
+ break;
+ case PS:
+ break;
+ default:
+ UNREACHABLE();
+ };
+ break;
+ case SPECIAL:
+ switch (instr->FunctionFieldRaw()) {
+ case JR: {
+ Instruction* branch_delay_instr = reinterpret_cast<Instruction*>(
+ current_pc+Instruction::kInstructionSize);
+ BranchDelayInstructionDecode(branch_delay_instr);
+ set_pc(next_pc);
+ pc_modified_ = true;
+ break;
+ }
+ case JALR: {
+ Instruction* branch_delay_instr = reinterpret_cast<Instruction*>(
+ current_pc+Instruction::kInstructionSize);
+ BranchDelayInstructionDecode(branch_delay_instr);
+ set_register(31, current_pc + 2* Instruction::kInstructionSize);
+ set_pc(next_pc);
+ pc_modified_ = true;
+ break;
+ }
+ // Instructions using HI and LO registers.
+ case MULT:
+ case MULTU:
+ break;
+ case DIV:
+ // Divide by zero was checked in the configuration step.
+ set_register(LO, rs / rt);
+ set_register(HI, rs % rt);
+ break;
+ case DIVU:
+ set_register(LO, rs_u / rt_u);
+ set_register(HI, rs_u % rt_u);
+ break;
+ // Break and trap instructions
+ case BREAK:
+ case TGE:
+ case TGEU:
+ case TLT:
+ case TLTU:
+ case TEQ:
+ case TNE:
+ if (do_interrupt) {
+ SoftwareInterrupt(instr);
+ }
+ break;
+ default: // For other special opcodes we do the default operation.
+ set_register(rd_reg, alu_out);
+ };
+ break;
+ case SPECIAL2:
+ switch (instr->FunctionFieldRaw()) {
+ case MUL:
+ set_register(rd_reg, alu_out);
+ // HI and LO are UNPREDICTABLE after the operation.
+ set_register(LO, Unpredictable);
+ set_register(HI, Unpredictable);
+ break;
+ default:
+ UNREACHABLE();
+ }
+ break;
+ // Unimplemented opcodes raised an error in the configuration step before,
+ // so we can use the default here to set the destination register in common
+ // cases.
+ default:
+ set_register(rd_reg, alu_out);
+ };
+}
+
+// Type 2: instructions using a 16 bytes immediate. (eg: addi, beq)
+void Simulator::DecodeTypeImmediate(Instruction* instr) {
+ // Instruction fields
+ Opcode op = instr->OpcodeFieldRaw();
+ int32_t rs = get_register(instr->RsField());
+ uint32_t rs_u = static_cast<uint32_t>(rs);
+ int32_t rt_reg = instr->RtField(); // destination register
+ int32_t rt = get_register(rt_reg);
+ int16_t imm16 = instr->Imm16Field();
+
+ int32_t ft_reg = instr->FtField(); // destination register
+ int32_t ft = get_register(ft_reg);
+
+ // zero extended immediate
+ uint32_t oe_imm16 = 0xffff & imm16;
+ // sign extended immediate
+ int32_t se_imm16 = imm16;
+
+ // Get current pc.
+ int32_t current_pc = get_pc();
+ // Next pc.
+ int32_t next_pc = bad_ra;
+
+ // Used for conditional branch instructions
+ bool do_branch = false;
+ bool execute_branch_delay_instruction = false;
+
+ // Used for arithmetic instructions
+ int32_t alu_out = 0;
+ // Floating point
+ double fp_out = 0.0;
+
+ // Used for memory instructions
+ int32_t addr = 0x0;
+
+ // ---------- Configuration (and execution for REGIMM)
+ switch (op) {
+ // ------------- COP1. Coprocessor instructions
+ case COP1:
+ switch (instr->RsFieldRaw()) {
+ case BC1: // branch on coprocessor condition
+ UNIMPLEMENTED_MIPS();
+ break;
+ default:
+ UNREACHABLE();
+ };
+ break;
+ // ------------- REGIMM class
+ case REGIMM:
+ switch (instr->RtFieldRaw()) {
+ case BLTZ:
+ do_branch = (rs < 0);
+ break;
+ case BLTZAL:
+ do_branch = rs < 0;
+ break;
+ case BGEZ:
+ do_branch = rs >= 0;
+ break;
+ case BGEZAL:
+ do_branch = rs >= 0;
+ break;
+ default:
+ UNREACHABLE();
+ };
+ switch (instr->RtFieldRaw()) {
+ case BLTZ:
+ case BLTZAL:
+ case BGEZ:
+ case BGEZAL:
+ // Branch instructions common part.
+ execute_branch_delay_instruction = true;
+ // Set next_pc
+ if (do_branch) {
+ next_pc = current_pc + (imm16 << 2) + Instruction::kInstructionSize;
+ if (instr->IsLinkingInstruction()) {
+ set_register(31, current_pc + kBranchReturnOffset);
+ }
+ } else {
+ next_pc = current_pc + kBranchReturnOffset;
+ }
+ default:
+ break;
+ };
+ break; // case REGIMM
+ // ------------- Branch instructions
+ // When comparing to zero, the encoding of rt field is always 0, so we don't
+ // need to replace rt with zero.
+ case BEQ:
+ do_branch = (rs == rt);
+ break;
+ case BNE:
+ do_branch = rs != rt;
+ break;
+ case BLEZ:
+ do_branch = rs <= 0;
+ break;
+ case BGTZ:
+ do_branch = rs > 0;
+ break;
+ // ------------- Arithmetic instructions
+ case ADDI:
+ if (HaveSameSign(rs, se_imm16)) {
+ if (rs > 0) {
+ exceptions[kIntegerOverflow] = rs > (Registers::kMaxValue - se_imm16);
+ } else if (rs < 0) {
+ exceptions[kIntegerUnderflow] =
+ rs < (Registers::kMinValue - se_imm16);
+ }
+ }
+ alu_out = rs + se_imm16;
+ break;
+ case ADDIU:
+ alu_out = rs + se_imm16;
+ break;
+ case SLTI:
+ alu_out = (rs < se_imm16) ? 1 : 0;
+ break;
+ case SLTIU:
+ alu_out = (rs_u < static_cast<uint32_t>(se_imm16)) ? 1 : 0;
+ break;
+ case ANDI:
+ alu_out = rs & oe_imm16;
+ break;
+ case ORI:
+ alu_out = rs | oe_imm16;
+ break;
+ case XORI:
+ alu_out = rs ^ oe_imm16;
+ break;
+ case LUI:
+ alu_out = (oe_imm16 << 16);
+ break;
+ // ------------- Memory instructions
+ case LB:
+ addr = rs + se_imm16;
+ alu_out = ReadB(addr);
+ break;
+ case LW:
+ addr = rs + se_imm16;
+ alu_out = ReadW(addr, instr);
+ break;
+ case LBU:
+ addr = rs + se_imm16;
+ alu_out = ReadBU(addr);
+ break;
+ case SB:
+ addr = rs + se_imm16;
+ break;
+ case SW:
+ addr = rs + se_imm16;
+ break;
+ case LWC1:
+ addr = rs + se_imm16;
+ alu_out = ReadW(addr, instr);
+ break;
+ case LDC1:
+ addr = rs + se_imm16;
+ fp_out = ReadD(addr, instr);
+ break;
+ case SWC1:
+ case SDC1:
+ addr = rs + se_imm16;
+ break;
+ default:
+ UNREACHABLE();
+ };
+
+ // ---------- Raise exceptions triggered.
+ SignalExceptions();
+
+ // ---------- Execution
+ switch (op) {
+ // ------------- Branch instructions
+ case BEQ:
+ case BNE:
+ case BLEZ:
+ case BGTZ:
+ // Branch instructions common part.
+ execute_branch_delay_instruction = true;
+ // Set next_pc
+ if (do_branch) {
+ next_pc = current_pc + (imm16 << 2) + Instruction::kInstructionSize;
+ if (instr->IsLinkingInstruction()) {
+ set_register(31, current_pc + 2* Instruction::kInstructionSize);
+ }
+ } else {
+ next_pc = current_pc + 2 * Instruction::kInstructionSize;
+ }
+ break;
+ // ------------- Arithmetic instructions
+ case ADDI:
+ case ADDIU:
+ case SLTI:
+ case SLTIU:
+ case ANDI:
+ case ORI:
+ case XORI:
+ case LUI:
+ set_register(rt_reg, alu_out);
+ break;
+ // ------------- Memory instructions
+ case LB:
+ case LW:
+ case LBU:
+ set_register(rt_reg, alu_out);
+ break;
+ case SB:
+ WriteB(addr, static_cast<int8_t>(rt));
+ break;
+ case SW:
+ WriteW(addr, rt, instr);
+ break;
+ case LWC1:
+ set_fpu_register(ft_reg, alu_out);
+ break;
+ case LDC1:
+ set_fpu_register_double(ft_reg, fp_out);
+ break;
+ case SWC1:
+ addr = rs + se_imm16;
+ WriteW(addr, get_fpu_register(ft_reg), instr);
+ break;
+ case SDC1:
+ addr = rs + se_imm16;
+ WriteD(addr, ft, instr);
+ break;
+ default:
+ break;
+ };
+
+
+ if (execute_branch_delay_instruction) {
+ // Execute branch delay slot
+ // We don't check for end_sim_pc. First it should not be met as the current
+ // pc is valid. Secondly a jump should always execute its branch delay slot.
+ Instruction* branch_delay_instr =
+ reinterpret_cast<Instruction*>(current_pc+Instruction::kInstructionSize);
+ BranchDelayInstructionDecode(branch_delay_instr);
+ }
+
+ // If needed update pc after the branch delay execution.
+ if (next_pc != bad_ra) {
+ set_pc(next_pc);
+ }
+}
+
+// Type 3: instructions using a 26 bytes immediate. (eg: j, jal)
+void Simulator::DecodeTypeJump(Instruction* instr) {
+ // Get current pc.
+ int32_t current_pc = get_pc();
+ // Get unchanged bits of pc.
+ int32_t pc_high_bits = current_pc & 0xf0000000;
+ // Next pc
+ int32_t next_pc = pc_high_bits | (instr->Imm26Field() << 2);
+
+ // Execute branch delay slot
+ // We don't check for end_sim_pc. First it should not be met as the current pc
+ // is valid. Secondly a jump should always execute its branch delay slot.
+ Instruction* branch_delay_instr =
+ reinterpret_cast<Instruction*>(current_pc+Instruction::kInstructionSize);
+ BranchDelayInstructionDecode(branch_delay_instr);
+
+ // Update pc and ra if necessary.
+ // Do this after the branch delay execution.
+ if (instr->IsLinkingInstruction()) {
+ set_register(31, current_pc + 2* Instruction::kInstructionSize);
+ }
+ set_pc(next_pc);
+ pc_modified_ = true;
+}
+
+// Executes the current instruction.
+void Simulator::InstructionDecode(Instruction* instr) {
+ pc_modified_ = false;
+ if (::v8::internal::FLAG_trace_sim) {
+ disasm::NameConverter converter;
+ disasm::Disassembler dasm(converter);
+ // use a reasonably large buffer
+ v8::internal::EmbeddedVector<char, 256> buffer;
+ dasm.InstructionDecode(buffer,
+ reinterpret_cast<byte_*>(instr));
+ PrintF(" 0x%08x %s\n", instr, buffer.start());
+ }
+
+ switch (instr->InstructionType()) {
+ case Instruction::kRegisterType:
+ DecodeTypeRegister(instr);
+ break;
+ case Instruction::kImmediateType:
+ DecodeTypeImmediate(instr);
+ break;
+ case Instruction::kJumpType:
+ DecodeTypeJump(instr);
+ break;
+ default:
+ UNSUPPORTED();
+ }
+ if (!pc_modified_) {
+ set_register(pc, reinterpret_cast<int32_t>(instr) +
+ Instruction::kInstructionSize);
+ }
+}
+
+
+
+void Simulator::Execute() {
+ // Get the PC to simulate. Cannot use the accessor here as we need the
+ // raw PC value and not the one used as input to arithmetic instructions.
+ int program_counter = get_pc();
+ if (::v8::internal::FLAG_stop_sim_at == 0) {
+ // Fast version of the dispatch loop without checking whether the simulator
+ // should be stopping at a particular executed instruction.
+ while (program_counter != end_sim_pc) {
+ Instruction* instr = reinterpret_cast<Instruction*>(program_counter);
+ icount_++;
+ InstructionDecode(instr);
+ program_counter = get_pc();
+ }
+ } else {
+ // FLAG_stop_sim_at is at the non-default value. Stop in the debugger when
+ // we reach the particular instuction count.
+ while (program_counter != end_sim_pc) {
+ Instruction* instr = reinterpret_cast<Instruction*>(program_counter);
+ icount_++;
+ if (icount_ == ::v8::internal::FLAG_stop_sim_at) {
+ Debugger dbg(this);
+ dbg.Debug();
+ } else {
+ InstructionDecode(instr);
+ }
+ program_counter = get_pc();
+ }
+ }
+}
+
+
+int32_t Simulator::Call(byte_* entry, int argument_count, ...) {
+ va_list parameters;
+ va_start(parameters, argument_count);
+ // Setup arguments
+
+ // First four arguments passed in registers.
+ ASSERT(argument_count >= 4);
+ set_register(a0, va_arg(parameters, int32_t));
+ set_register(a1, va_arg(parameters, int32_t));
+ set_register(a2, va_arg(parameters, int32_t));
+ set_register(a3, va_arg(parameters, int32_t));
+
+ // Remaining arguments passed on stack.
+ int original_stack = get_register(sp);
+ // Compute position of stack on entry to generated code.
+ int entry_stack = (original_stack - (argument_count - 4) * sizeof(int32_t)
+ - kArgsSlotsSize);
+ if (OS::ActivationFrameAlignment() != 0) {
+ entry_stack &= -OS::ActivationFrameAlignment();
+ }
+ // Store remaining arguments on stack, from low to high memory.
+ intptr_t* stack_argument = reinterpret_cast<intptr_t*>(entry_stack);
+ for (int i = 4; i < argument_count; i++) {
+ stack_argument[i - 4 + kArgsSlotsNum] = va_arg(parameters, int32_t);
+ }
+ va_end(parameters);
+ set_register(sp, entry_stack);
+
+ // Prepare to execute the code at entry
+ set_register(pc, reinterpret_cast<int32_t>(entry));
+ // Put down marker for end of simulation. The simulator will stop simulation
+ // when the PC reaches this value. By saving the "end simulation" value into
+ // the LR the simulation stops when returning to this call point.
+ set_register(ra, end_sim_pc);
+
+ // Remember the values of callee-saved registers.
+ // The code below assumes that r9 is not used as sb (static base) in
+ // simulator code and therefore is regarded as a callee-saved register.
+ int32_t s0_val = get_register(s0);
+ int32_t s1_val = get_register(s1);
+ int32_t s2_val = get_register(s2);
+ int32_t s3_val = get_register(s3);
+ int32_t s4_val = get_register(s4);
+ int32_t s5_val = get_register(s5);
+ int32_t s6_val = get_register(s6);
+ int32_t s7_val = get_register(s7);
+ int32_t gp_val = get_register(gp);
+ int32_t sp_val = get_register(sp);
+ int32_t fp_val = get_register(fp);
+
+ // Setup the callee-saved registers with a known value. To be able to check
+ // that they are preserved properly across JS execution.
+ int32_t callee_saved_value = icount_;
+ set_register(s0, callee_saved_value);
+ set_register(s1, callee_saved_value);
+ set_register(s2, callee_saved_value);
+ set_register(s3, callee_saved_value);
+ set_register(s4, callee_saved_value);
+ set_register(s5, callee_saved_value);
+ set_register(s6, callee_saved_value);
+ set_register(s7, callee_saved_value);
+ set_register(gp, callee_saved_value);
+ set_register(fp, callee_saved_value);
+
+ // Start the simulation
+ Execute();
+
+ // Check that the callee-saved registers have been preserved.
+ CHECK_EQ(callee_saved_value, get_register(s0));
+ CHECK_EQ(callee_saved_value, get_register(s1));
+ CHECK_EQ(callee_saved_value, get_register(s2));
+ CHECK_EQ(callee_saved_value, get_register(s3));
+ CHECK_EQ(callee_saved_value, get_register(s4));
+ CHECK_EQ(callee_saved_value, get_register(s5));
+ CHECK_EQ(callee_saved_value, get_register(s6));
+ CHECK_EQ(callee_saved_value, get_register(s7));
+ CHECK_EQ(callee_saved_value, get_register(gp));
+ CHECK_EQ(callee_saved_value, get_register(fp));
+
+ // Restore callee-saved registers with the original value.
+ set_register(s0, s0_val);
+ set_register(s1, s1_val);
+ set_register(s2, s2_val);
+ set_register(s3, s3_val);
+ set_register(s4, s4_val);
+ set_register(s5, s5_val);
+ set_register(s6, s6_val);
+ set_register(s7, s7_val);
+ set_register(gp, gp_val);
+ set_register(sp, sp_val);
+ set_register(fp, fp_val);
+
+ // Pop stack passed arguments.
+ CHECK_EQ(entry_stack, get_register(sp));
+ set_register(sp, original_stack);
+
+ int32_t result = get_register(v0);
+ return result;
+}
+
+
+uintptr_t Simulator::PushAddress(uintptr_t address) {
+ int new_sp = get_register(sp) - sizeof(uintptr_t);
+ uintptr_t* stack_slot = reinterpret_cast<uintptr_t*>(new_sp);
+ *stack_slot = address;
+ set_register(sp, new_sp);
+ return new_sp;
+}
+
+
+uintptr_t Simulator::PopAddress() {
+ int current_sp = get_register(sp);
+ uintptr_t* stack_slot = reinterpret_cast<uintptr_t*>(current_sp);
+ uintptr_t address = *stack_slot;
+ set_register(sp, current_sp + sizeof(uintptr_t));
+ return address;
+}
+
+
+#undef UNSUPPORTED
+
+} } // namespace assembler::mips
+
+#endif // !defined(__mips)
+