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gerrit-public.fairphone.software / fp2-dev / platform / external / v8 / 144045c95df339bcbcf35374401289e1eefc1d85 / . / src / mips / simulator-mips.cc
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// 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)