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sdk/runtime/vm/simulator_arm.cc
T
regis@google.com 5675b85979 Generate first ARM assembler test and execute (simulate) it. 
RFC: First draft showing how generated ARM code accesses GC'ed objects and
accesses patched call targets.
Review URL: https://codereview.chromium.org//12224024

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@18200 260f80e4-7a28-3924-810f-c04153c831b5
2013-02-07 00:55:47 +00:00

2743 lines
84 KiB
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// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#include <math.h> // for isnan.
#include <setjmp.h>
#include <stdlib.h>
#include "vm/globals.h"
#if defined(TARGET_ARCH_ARM)
// Only build the simulator if not compiling for real ARM hardware.
#if !defined(HOST_ARCH_ARM)
#include "vm/simulator.h"
#include "vm/assembler.h"
#include "vm/constants_arm.h"
#include "vm/disassembler.h"
#include "vm/native_arguments.h"
#include "vm/thread.h"
namespace dart {
DEFINE_FLAG(bool, trace_sim, false, "Trace simulator execution.");
DEFINE_FLAG(int, stop_sim_at, 0, "Address to stop simulator at.");
// This macro provides a platform independent use of sscanf. The reason for
// SScanF not being implemented in a platform independent way through
// OS in the same way as SNPrint is that the Windows C Run-Time
// Library does not provide vsscanf.
#define SScanF sscanf // NOLINT
// Unimplemented counter class for debugging and measurement purposes.
class StatsCounter {
public:
explicit StatsCounter(const char* name) {
// UNIMPLEMENTED();
}
void Increment() {
// UNIMPLEMENTED();
}
};
// SimulatorSetjmpBuffer are linked together, and the last created one
// is referenced by the Simulator. When an exception is thrown, the exception
// runtime looks at where to jump and finds the corresponding
// SimulatorSetjmpBuffer based on the stack pointer of the exception handler.
// The runtime then does a Longjmp on that buffer to return to the simulator.
class SimulatorSetjmpBuffer {
public:
int Setjmp() { return setjmp(buffer_); }
void Longjmp() {
// "This" is now the last setjmp buffer.
simulator_->set_last_setjmp_buffer(this);
longjmp(buffer_, 1);
}
explicit SimulatorSetjmpBuffer(Simulator* sim) {
simulator_ = sim;
link_ = sim->last_setjmp_buffer();
sim->set_last_setjmp_buffer(this);
sp_ = sim->get_register(SP);
}
~SimulatorSetjmpBuffer() {
ASSERT(simulator_->last_setjmp_buffer() == this);
simulator_->set_last_setjmp_buffer(link_);
}
SimulatorSetjmpBuffer* link() { return link_; }
int32_t sp() { return sp_; }
private:
int32_t sp_;
Simulator* simulator_;
SimulatorSetjmpBuffer* link_;
jmp_buf buffer_;
friend class Simulator;
};
// The SimulatorDebugger class is used by the simulator while debugging
// simulated ARM code.
class SimulatorDebugger {
public:
explicit SimulatorDebugger(Simulator* sim);
~SimulatorDebugger();
void Stop(Instr* instr, const char* message);
void Debug();
char* ReadLine(const char* prompt);
private:
static const int32_t kSimulatorBreakpointInstr = // svc #kBreakpointSvcCode
((AL << kConditionShift) | (0xf << 24) | kBreakpointSvcCode);
static const int32_t kNopInstr = // nop
((AL << kConditionShift) | (0x32 << 20) | (0xf << 12));
Simulator* sim_;
bool GetValue(char* desc, uint32_t* value);
bool GetFValue(char* desc, float* value);
bool GetDValue(char* desc, double* value);
// Set or delete a breakpoint. Returns true if successful.
bool SetBreakpoint(Instr* breakpc);
bool DeleteBreakpoint(Instr* breakpc);
// Undo and redo all breakpoints. This is needed to bracket disassembly and
// execution to skip past breakpoints when run from the debugger.
void UndoBreakpoints();
void RedoBreakpoints();
};
SimulatorDebugger::SimulatorDebugger(Simulator* sim) {
sim_ = sim;
}
SimulatorDebugger::~SimulatorDebugger() {
}
void SimulatorDebugger::Stop(Instr* instr, const char* message) {
OS::Print("Simulator hit %s\n", message);
Debug();
}
static Register LookupCoreRegisterByName(const char* name) {
static const char* kNames[] = {
"r0", "r1", "r2", "r3",
"r4", "r5", "r6", "r7",
"r8", "r9", "r10", "r11",
"r12", "r13", "r14", "r15",
"pc", "lr", "sp", "ip",
"fp", "sl"
};
static const Register kRegisters[] = {
R0, R1, R2, R3,
R4, R5, R6, R7,
R8, R9, R10, R11,
R12, R13, R14, R15,
PC, LR, SP, IP,
FP, R10
};
ASSERT(ARRAY_SIZE(kNames) == ARRAY_SIZE(kRegisters));
for (unsigned i = 0; i < ARRAY_SIZE(kNames); i++) {
if (strcmp(kNames[i], name) == 0) {
return kRegisters[i];
}
}
return kNoRegister;
}
static SRegister LookupSRegisterByName(const char* name) {
int reg_nr = -1;
bool ok = SScanF(name, "s%d", &reg_nr);
if (ok && (0 <= reg_nr) && (reg_nr < kNumberOfSRegisters)) {
return static_cast<SRegister>(reg_nr);
}
return kNoSRegister;
}
static DRegister LookupDRegisterByName(const char* name) {
int reg_nr = -1;
bool ok = SScanF(name, "d%d", &reg_nr);
if (ok && (0 <= reg_nr) && (reg_nr < kNumberOfDRegisters)) {
return static_cast<DRegister>(reg_nr);
}
return kNoDRegister;
}
bool SimulatorDebugger::GetValue(char* desc, uint32_t* value) {
Register reg = LookupCoreRegisterByName(desc);
if (reg != kNoRegister) {
if (reg == PC) {
*value = sim_->get_pc();
} else {
*value = sim_->get_register(reg);
}
return true;
}
if ((desc[0] == '*')) {
uint32_t addr;
if (GetValue(desc + 1, &addr)) {
*value = *(reinterpret_cast<uint32_t*>(addr));
return true;
}
}
bool retval = SScanF(desc, "0x%x", value) == 1;
if (!retval) {
retval = SScanF(desc, "%x", value) == 1;
}
return retval;
}
bool SimulatorDebugger::GetFValue(char* desc, float* value) {
SRegister sreg = LookupSRegisterByName(desc);
if (sreg != kNoSRegister) {
*value = sim_->get_sregister(sreg);
return true;
}
if ((desc[0] == '*')) {
uint32_t addr;
if (GetValue(desc + 1, &addr)) {
*value = *(reinterpret_cast<float*>(addr));
return true;
}
}
return false;
}
bool SimulatorDebugger::GetDValue(char* desc, double* value) {
DRegister dreg = LookupDRegisterByName(desc);
if (dreg != kNoDRegister) {
*value = sim_->get_dregister(dreg);
return true;
}
if ((desc[0] == '*')) {
uint32_t addr;
if (GetValue(desc + 1, &addr)) {
*value = *(reinterpret_cast<double*>(addr));
return true;
}
}
return false;
}
bool SimulatorDebugger::SetBreakpoint(Instr* 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 SimulatorDebugger::DeleteBreakpoint(Instr* breakpc) {
if (sim_->break_pc_ != NULL) {
sim_->break_pc_->SetInstructionBits(sim_->break_instr_);
}
sim_->break_pc_ = NULL;
sim_->break_instr_ = 0;
return true;
}
void SimulatorDebugger::UndoBreakpoints() {
if (sim_->break_pc_ != NULL) {
sim_->break_pc_->SetInstructionBits(sim_->break_instr_);
}
}
void SimulatorDebugger::RedoBreakpoints() {
if (sim_->break_pc_ != NULL) {
sim_->break_pc_->SetInstructionBits(kSimulatorBreakpointInstr);
}
}
void SimulatorDebugger::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) {
if (last_pc != sim_->get_pc()) {
last_pc = sim_->get_pc();
Disassembler::Disassemble(last_pc, last_pc + Instr::kInstrSize);
}
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, "h") == 0) || (strcmp(cmd, "help") == 0)) {
OS::Print("c/cont -- continue execution\n"
"disasm -- disassemble instrs at current pc location\n"
" other variants are:\n"
" disasm <address>\n"
" disasm <address> <number_of_instructions>\n"
" by default 10 instrs are disassembled\n"
"del -- delete breakpoints\n"
"flags -- print flag values\n"
"gdb -- transfer control to gdb\n"
"h/help -- print this help string\n"
"break <address> -- set break point at specified address\n"
"p/print <reg or value or *addr> -- print integer value\n"
"pf/printfloat <sreg or *addr> -- print float value\n"
"pd/printdouble <dreg or *addr> -- print double value\n"
"po/printobject <*reg or *addr> -- print object\n"
"si/stepi -- single step an instruction\n"
"unstop -- if current pc is a stop instr make it a nop\n");
} else if ((strcmp(cmd, "si") == 0) || (strcmp(cmd, "stepi") == 0)) {
sim_->InstructionDecode(reinterpret_cast<Instr*>(sim_->get_pc()));
} else if ((strcmp(cmd, "c") == 0) || (strcmp(cmd, "cont") == 0)) {
// Execute the one instruction we broke at with breakpoints disabled.
sim_->InstructionDecode(reinterpret_cast<Instr*>(sim_->get_pc()));
// Leave the debugger shell.
done = true;
} else if ((strcmp(cmd, "p") == 0) || (strcmp(cmd, "print") == 0)) {
if (args == 2) {
uint32_t value;
if (GetValue(arg1, &value)) {
OS::Print("%s: %u 0x%x\n", arg1, value, value);
} else {
OS::Print("%s unrecognized\n", arg1);
}
} else {
OS::Print("print <reg or value or *addr>\n");
}
} else if ((strcmp(cmd, "pf") == 0) || (strcmp(cmd, "printfloat") == 0)) {
if (args == 2) {
float fvalue;
if (GetFValue(arg1, &fvalue)) {
uint32_t value = bit_cast<uint32_t, float>(fvalue);
OS::Print("%s: 0%u 0x%x %.8g\n", arg1, value, value, fvalue);
} else {
OS::Print("%s unrecognized\n", arg1);
}
} else {
OS::Print("printfloat <sreg or *addr>\n");
}
} else if ((strcmp(cmd, "pd") == 0) ||
(strcmp(cmd, "printdouble") == 0)) {
if (args == 2) {
double dvalue;
if (GetDValue(arg1, &dvalue)) {
uint64_t long_value = bit_cast<uint64_t, double>(dvalue);
OS::Print("%s: %llu 0x%llx %.8g\n",
arg1, long_value, long_value, dvalue);
} else {
OS::Print("%s unrecognized\n", arg1);
}
} else {
OS::Print("printdouble <dreg or *addr>\n");
}
} else if ((strcmp(cmd, "po") == 0) ||
(strcmp(cmd, "printobject") == 0)) {
if (args == 2) {
uint32_t value;
// Make the dereferencing '*' optional.
if (((arg1[0] == '*') && GetValue(arg1 + 1, &value)) ||
GetValue(arg1, &value)) {
if (Isolate::Current()->heap()->Contains(value)) {
OS::Print("%s: \n", arg1);
#if defined(DEBUG)
const Object& obj = Object::Handle(
reinterpret_cast<RawObject*>(value));
obj.Print();
#endif // defined(DEBUG)
} else {
OS::Print("0x%x is not an object reference\n", value);
}
} else {
OS::Print("%s unrecognized\n", arg1);
}
} else {
OS::Print("printobject <*reg or *addr>\n");
}
} else if (strcmp(cmd, "disasm") == 0) {
uint32_t start = 0;
uint32_t end = 0;
if (args == 1) {
start = sim_->get_pc();
end = start + (10 * Instr::kInstrSize);
} else if (args == 2) {
if (GetValue(arg1, &start)) {
// no length parameter passed, assume 10 instructions
end = start + (10 * Instr::kInstrSize);
}
} else {
uint32_t length;
if (GetValue(arg1, &start) && GetValue(arg2, &length)) {
end = start + (length * Instr::kInstrSize);
}
}
Disassembler::Disassemble(start, end);
} else if (strcmp(cmd, "gdb") == 0) {
OS::Print("relinquishing control to gdb\n");
OS::DebugBreak();
OS::Print("regaining control from gdb\n");
} else if (strcmp(cmd, "break") == 0) {
if (args == 2) {
uint32_t addr;
if (GetValue(arg1, &addr)) {
if (!SetBreakpoint(reinterpret_cast<Instr*>(addr))) {
OS::Print("setting breakpoint failed\n");
}
} else {
OS::Print("%s unrecognized\n", arg1);
}
} else {
OS::Print("break <addr>\n");
}
} else if (strcmp(cmd, "del") == 0) {
if (!DeleteBreakpoint(NULL)) {
OS::Print("deleting breakpoint failed\n");
}
} else if (strcmp(cmd, "flags") == 0) {
OS::Print("APSR: ");
OS::Print("N flag: %d; ", sim_->n_flag_);
OS::Print("Z flag: %d; ", sim_->z_flag_);
OS::Print("C flag: %d; ", sim_->c_flag_);
OS::Print("V flag: %d\n", sim_->v_flag_);
OS::Print("FPSCR: ");
OS::Print("N flag: %d; ", sim_->fp_n_flag_);
OS::Print("Z flag: %d; ", sim_->fp_z_flag_);
OS::Print("C flag: %d; ", sim_->fp_c_flag_);
OS::Print("V flag: %d\n", sim_->fp_v_flag_);
} else if (strcmp(cmd, "unstop") == 0) {
intptr_t stop_pc = sim_->get_pc() - Instr::kInstrSize;
Instr* stop_instr = reinterpret_cast<Instr*>(stop_pc);
if (stop_instr->IsSvc() || stop_instr->IsBkpt()) {
stop_instr->SetInstructionBits(kNopInstr);
} else {
OS::Print("Not at debugger stop.\n");
}
} else {
OS::Print("Unknown command: %s\n", cmd);
}
}
delete[] 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
}
char* SimulatorDebugger::ReadLine(const char* prompt) {
char* result = NULL;
char line_buf[256];
int offset = 0;
bool keep_going = true;
fprintf(stdout, "%s", prompt);
fflush(stdout);
while (keep_going) {
if (fgets(line_buf, sizeof(line_buf), stdin) == NULL) {
// fgets got an error. Just give up.
if (result != NULL) {
delete[] result;
}
return NULL;
}
int len = strlen(line_buf);
if (len > 1 &&
line_buf[len - 2] == '\\' &&
line_buf[len - 1] == '\n') {
// When we read a line that ends with a "\" we remove the escape and
// append the remainder.
line_buf[len - 2] = '\n';
line_buf[len - 1] = 0;
len -= 1;
} else if ((len > 0) && (line_buf[len - 1] == '\n')) {
// Since we read a new line we are done reading the line. This
// will exit the loop after copying this buffer into the result.
keep_going = false;
}
if (result == NULL) {
// Allocate the initial result and make room for the terminating '\0'
result = new char[len + 1];
if (result == NULL) {
// OOM, so cannot readline anymore.
return NULL;
}
} else {
// Allocate a new result with enough room for the new addition.
int new_len = offset + len + 1;
char* new_result = new char[new_len];
if (new_result == NULL) {
// OOM, free the buffer allocated so far and return NULL.
delete[] result;
return NULL;
} else {
// Copy the existing input into the new array and set the new
// array as the result.
memmove(new_result, result, offset);
delete[] result;
result = new_result;
}
}
// Copy the newly read line into the result.
memmove(result + offset, line_buf, len);
offset += len;
}
ASSERT(result != NULL);
result[offset] = '\0';
return result;
}
// Synchronization primitives support.
Mutex* Simulator::exclusive_access_lock_ = NULL;
Simulator::AddressTag Simulator::exclusive_access_state_[kNumAddressTags];
int Simulator::next_address_tag_;
void Simulator::SetExclusiveAccess(uword addr) {
Isolate* isolate = Isolate::Current();
ASSERT(isolate != NULL);
int i = 0;
while ((i < kNumAddressTags) &&
(exclusive_access_state_[i].isolate != isolate)) {
i++;
}
if (i == kNumAddressTags) {
i = next_address_tag_;
if (++next_address_tag_ == kNumAddressTags) next_address_tag_ = 0;
exclusive_access_state_[i].isolate = isolate;
}
exclusive_access_state_[i].addr = addr;
}
bool Simulator::HasExclusiveAccessAndOpen(uword addr) {
Isolate* isolate = Isolate::Current();
ASSERT(isolate != NULL);
bool result = false;
for (int i = 0; i < kNumAddressTags; i++) {
if (exclusive_access_state_[i].isolate == isolate) {
if (exclusive_access_state_[i].addr == addr) {
result = true;
}
exclusive_access_state_[i].addr = NULL;
continue;
}
if (exclusive_access_state_[i].addr == addr) {
exclusive_access_state_[i].addr = NULL;
}
}
return result;
}
void Simulator::InitOnce() {
// Setup exclusive access state.
exclusive_access_lock_ = new Mutex();
for (int i = 0; i < kNumAddressTags; i++) {
exclusive_access_state_[i].isolate = NULL;
exclusive_access_state_[i].addr = NULL;
}
next_address_tag_ = 0;
}
Simulator::Simulator() {
// Setup simulator support first. Some of this information is needed to
// setup the architecture state.
// We allocate the stack here, the size is computed as the sum of
// the size specified by the user and the buffer space needed for
// handling stack overflow exceptions. To be safe in potential
// stack underflows we also add some underflow buffer space.
stack_ = new char[(Isolate::GetSpecifiedStackSize() +
Isolate::kStackSizeBuffer +
kSimulatorStackUnderflowSize)];
pc_modified_ = false;
icount_ = 0;
break_pc_ = NULL;
break_instr_ = 0;
last_setjmp_buffer_ = NULL;
// Setup architecture state.
// All registers are initialized to zero to start with.
for (int i = 0; i < kNumberOfCpuRegisters; i++) {
registers_[i] = 0;
}
n_flag_ = false;
z_flag_ = false;
c_flag_ = false;
v_flag_ = false;
// The sp is initialized to point to the bottom (high address) of the
// allocated stack area.
registers_[SP] = StackTop();
// The lr 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] = kBadLR;
registers_[LR] = kBadLR;
// All double-precision registers are initialized to zero.
for (int i = 0; i < kNumberOfDRegisters; i++) {
dregisters_[i] = 0.0;
}
// Since VFP registers are overlapping, single-precision registers should
// already be initialized.
ASSERT(2*kNumberOfDRegisters >= kNumberOfSRegisters);
for (int i = 0; i < kNumberOfSRegisters; i++) {
ASSERT(sregisters_[i] == 0.0);
}
fp_n_flag_ = false;
fp_z_flag_ = false;
fp_c_flag_ = false;
fp_v_flag_ = false;
}
Simulator::~Simulator() {
delete[] stack_;
Isolate* isolate = Isolate::Current();
if (isolate != NULL) {
isolate->set_simulator(NULL);
}
}
// 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 svc (supervisor call) instruction that is handled by
// the simulator. We write the original destination of the jump just at a known
// offset from the svc instruction so the simulator knows what to call.
class Redirection {
public:
uword address_of_svc_instruction() {
return reinterpret_cast<uword>(&svc_instruction_);
}
void* external_function() const { return external_function_; }
uint32_t argument_count() const { return argument_count_; }
static Redirection* Get(void* external_function, uint32_t argument_count) {
Redirection* current;
for (current = list_; current != NULL; current = current->next_) {
if (current->external_function_ == external_function) return current;
}
return new Redirection(external_function, argument_count);
}
static Redirection* FromSvcInstruction(Instr* svc_instruction) {
char* addr_of_svc = reinterpret_cast<char*>(svc_instruction);
char* addr_of_redirection =
addr_of_svc - OFFSET_OF(Redirection, svc_instruction_);
return reinterpret_cast<Redirection*>(addr_of_redirection);
}
private:
static const int32_t kRedirectSvcInstruction =
((AL << kConditionShift) | (0xf << 24) | kRedirectionSvcCode);
Redirection(void* external_function, uint32_t argument_count)
: external_function_(external_function),
argument_count_(argument_count),
svc_instruction_(kRedirectSvcInstruction),
next_(list_) {
list_ = this;
}
void* external_function_;
const uint32_t argument_count_;
uint32_t svc_instruction_;
Redirection* next_;
static Redirection* list_;
};
Redirection* Redirection::list_ = NULL;
uword Simulator::RedirectExternalReference(void* function,
uint32_t argument_count) {
Redirection* redirection = Redirection::Get(function, argument_count);
return redirection->address_of_svc_instruction();
}
// Get the active Simulator for the current isolate.
Simulator* Simulator::Current() {
Simulator* simulator = Isolate::Current()->simulator();
if (simulator == NULL) {
simulator = new Simulator();
Isolate::Current()->set_simulator(simulator);
}
return simulator;
}
// 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(Register reg, int32_t value) {
ASSERT((reg >= 0) && (reg < kNumberOfCpuRegisters));
if (reg == PC) {
pc_modified_ = true;
}
registers_[reg] = 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(Register reg) const {
ASSERT((reg >= 0) && (reg < kNumberOfCpuRegisters));
return registers_[reg] + ((reg == PC) ? Instr::kPCReadOffset : 0);
}
// 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];
}
// Accessors for VFP register state.
void Simulator::set_sregister(SRegister reg, float value) {
ASSERT((reg >= 0) && (reg < kNumberOfSRegisters));
sregisters_[reg] = value;
}
float Simulator::get_sregister(SRegister reg) const {
ASSERT((reg >= 0) && (reg < kNumberOfSRegisters));
return sregisters_[reg];
}
void Simulator::set_dregister(DRegister reg, double value) {
ASSERT((reg >= 0) && (reg < kNumberOfDRegisters));
dregisters_[reg] = value;
}
double Simulator::get_dregister(DRegister reg) const {
ASSERT((reg >= 0) && (reg < kNumberOfDRegisters));
return dregisters_[reg];
}
void Simulator::HandleIllegalAccess(uword addr, Instr* instr) {
uword fault_pc = get_pc();
// The debugger will not be able to single step past this instruction, but
// it will be possible to disassemble the code and inspect registers.
char buffer[128];
snprintf(buffer, sizeof(buffer),
"illegal memory access at 0x%"Px", pc=0x%"Px"\n",
addr, fault_pc);
SimulatorDebugger dbg(this);
dbg.Stop(instr, buffer);
// The debugger will return control in non-interactive mode.
FATAL("Cannot continue execution after illegal memory access.");
}
// Processor versions prior to ARMv7 could not do unaligned reads and writes.
// On some ARM platforms an interrupt is caused. On others it does a funky
// rotation thing. However, from version v7, unaligned access is supported.
// 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 get the correct ARMv7-like behaviour on unaligned
// accesses, but we should actually not generate code accessing unaligned data,
// so we still want to know and abort if we encounter such code.
void Simulator::UnalignedAccess(const char* msg, uword addr, Instr* instr) {
// The debugger will not be able to single step past this instruction, but
// it will be possible to disassemble the code and inspect registers.
char buffer[64];
snprintf(buffer, sizeof(buffer),
"unaligned %s at 0x%"Px", pc=%p\n", msg, addr, instr);
SimulatorDebugger dbg(this);
dbg.Stop(instr, buffer);
// The debugger will return control in non-interactive mode.
FATAL("Cannot continue execution after unaligned access.");
}
int Simulator::ReadW(uword addr, Instr* instr) {
static StatsCounter counter_read_w("Simulated word reads");
counter_read_w.Increment();
if ((addr & 3) == 0) {
intptr_t* ptr = reinterpret_cast<intptr_t*>(addr);
return *ptr;
}
UnalignedAccess("read", addr, instr);
return 0;
}
void Simulator::WriteW(uword addr, int value, Instr* instr) {
static StatsCounter counter_write_w("Simulated word writes");
counter_write_w.Increment();
if ((addr & 3) == 0) {
intptr_t* ptr = reinterpret_cast<intptr_t*>(addr);
*ptr = value;
return;
}
UnalignedAccess("write", addr, instr);
}
uint16_t Simulator::ReadHU(uword addr, Instr* instr) {
static StatsCounter counter_read_hu("Simulated unsigned halfword reads");
counter_read_hu.Increment();
if ((addr & 1) == 0) {
uint16_t* ptr = reinterpret_cast<uint16_t*>(addr);
return *ptr;
}
UnalignedAccess("unsigned halfword read", addr, instr);
return 0;
}
int16_t Simulator::ReadH(uword addr, Instr* instr) {
static StatsCounter counter_read_h("Simulated signed halfword reads");
counter_read_h.Increment();
if ((addr & 1) == 0) {
int16_t* ptr = reinterpret_cast<int16_t*>(addr);
return *ptr;
}
UnalignedAccess("signed halfword read", addr, instr);
return 0;
}
void Simulator::WriteH(uword addr, uint16_t value, Instr* instr) {
static StatsCounter counter_write_h("Simulated halfword writes");
counter_write_h.Increment();
if ((addr & 1) == 0) {
uint16_t* ptr = reinterpret_cast<uint16_t*>(addr);
*ptr = value;
return;
}
UnalignedAccess("halfword write", addr, instr);
}
uint8_t Simulator::ReadBU(uword addr) {
static StatsCounter counter_read_bu("Simulated unsigned byte reads");
counter_read_bu.Increment();
uint8_t* ptr = reinterpret_cast<uint8_t*>(addr);
return *ptr;
}
int8_t Simulator::ReadB(uword addr) {
static StatsCounter counter_read_b("Simulated signed byte reads");
counter_read_b.Increment();
int8_t* ptr = reinterpret_cast<int8_t*>(addr);
return *ptr;
}
void Simulator::WriteB(uword addr, uint8_t value) {
static StatsCounter counter_write_b("Simulated byte writes");
counter_write_b.Increment();
uint8_t* ptr = reinterpret_cast<uint8_t*>(addr);
*ptr = value;
}
// Synchronization primitives support.
void Simulator::ClearExclusive() {
// This lock is initialized in Simulator::InitOnce().
MutexLocker ml(exclusive_access_lock_);
// Set exclusive access to open state for this isolate.
HasExclusiveAccessAndOpen(NULL);
}
int Simulator::ReadExclusiveW(uword addr, Instr* instr) {
// This lock is initialized in Simulator::InitOnce().
MutexLocker ml(exclusive_access_lock_);
SetExclusiveAccess(addr);
return ReadW(addr, instr);
}
int Simulator::WriteExclusiveW(uword addr, int value, Instr* instr) {
// This lock is initialized in Simulator::InitOnce().
MutexLocker ml(exclusive_access_lock_);
bool write_allowed = HasExclusiveAccessAndOpen(addr);
if (write_allowed) {
WriteW(addr, value, instr);
return 0; // Success.
}
return 1; // Failure.
}
uword Simulator::CompareExchange(uword* address,
uword compare_value,
uword new_value) {
// This lock is initialized in Simulator::InitOnce().
MutexLocker ml(exclusive_access_lock_);
uword value = *address;
if (value == compare_value) {
*address = new_value;
// Same effect on exclusive access state as a successful STREX.
HasExclusiveAccessAndOpen(reinterpret_cast<uword>(address));
} else {
// Same effect on exclusive access state as an LDREX.
SetExclusiveAccess(reinterpret_cast<uword>(address));
}
return value;
}
// Returns the top of the stack area to enable checking for stack pointer
// validity.
uintptr_t Simulator::StackTop() const {
// To be safe in potential stack underflows we leave some buffer above and
// set the stack top.
return reinterpret_cast<uintptr_t>(stack_) +
(Isolate::GetSpecifiedStackSize() + Isolate::kStackSizeBuffer);
}
// Unsupported instructions use Format to print an error and stop execution.
void Simulator::Format(Instr* instr, const char* format) {
OS::Print("Simulator found unsupported instruction:\n 0x%p: %s\n",
instr,
format);
UNIMPLEMENTED();
}
// Checks if the current instruction should be executed based on its
// condition bits.
bool Simulator::ConditionallyExecute(Instr* instr) {
switch (instr->ConditionField()) {
case EQ: return z_flag_;
case NE: return !z_flag_;
case CS: return c_flag_;
case CC: return !c_flag_;
case MI: return n_flag_;
case PL: return !n_flag_;
case VS: return v_flag_;
case VC: return !v_flag_;
case HI: return c_flag_ && !z_flag_;
case LS: return !c_flag_ || z_flag_;
case GE: return n_flag_ == v_flag_;
case LT: return n_flag_ != v_flag_;
case GT: return !z_flag_ && (n_flag_ == v_flag_);
case LE: return z_flag_ || (n_flag_ != v_flag_);
case AL: return true;
default: UNREACHABLE();
}
return false;
}
// Calculate and set the Negative and Zero flags.
void Simulator::SetNZFlags(int32_t val) {
n_flag_ = (val < 0);
z_flag_ = (val == 0);
}
// Set the Carry flag.
void Simulator::SetCFlag(bool val) {
c_flag_ = val;
}
// Set the oVerflow flag.
void Simulator::SetVFlag(bool val) {
v_flag_ = val;
}
// Calculate C flag value for additions.
bool Simulator::CarryFrom(int32_t left, int32_t right) {
uint32_t uleft = static_cast<uint32_t>(left);
uint32_t uright = static_cast<uint32_t>(right);
uint32_t urest = 0xffffffffU - uleft;
return (uright > urest);
}
// Calculate C flag value for subtractions.
bool Simulator::BorrowFrom(int32_t left, int32_t right) {
uint32_t uleft = static_cast<uint32_t>(left);
uint32_t uright = static_cast<uint32_t>(right);
return (uright > uleft);
}
// Calculate V flag value for additions and subtractions.
bool Simulator::OverflowFrom(int32_t alu_out,
int32_t left, int32_t right, bool addition) {
bool overflow;
if (addition) {
// operands have the same sign
overflow = ((left >= 0 && right >= 0) || (left < 0 && right < 0))
// and operands and result have different sign
&& ((left < 0 && alu_out >= 0) || (left >= 0 && alu_out < 0));
} else {
// operands have different signs
overflow = ((left < 0 && right >= 0) || (left >= 0 && right < 0))
// and first operand and result have different signs
&& ((left < 0 && alu_out >= 0) || (left >= 0 && alu_out < 0));
}
return overflow;
}
// Addressing Mode 1 - Data-processing operands:
// Get the value based on the shifter_operand with register.
int32_t Simulator::GetShiftRm(Instr* instr, bool* carry_out) {
Shift shift = instr->ShiftField();
int shift_amount = instr->ShiftAmountField();
int32_t result = get_register(instr->RmField());
if (instr->Bit(4) == 0) {
// by immediate
if ((shift == ROR) && (shift_amount == 0)) {
UNIMPLEMENTED();
return result;
} else if (((shift == LSR) || (shift == ASR)) && (shift_amount == 0)) {
shift_amount = 32;
}
switch (shift) {
case ASR: {
if (shift_amount == 0) {
if (result < 0) {
result = 0xffffffff;
*carry_out = true;
} else {
result = 0;
*carry_out = false;
}
} else {
result >>= (shift_amount - 1);
*carry_out = (result & 1) == 1;
result >>= 1;
}
break;
}
case LSL: {
if (shift_amount == 0) {
*carry_out = c_flag_;
} else {
result <<= (shift_amount - 1);
*carry_out = (result < 0);
result <<= 1;
}
break;
}
case LSR: {
if (shift_amount == 0) {
result = 0;
*carry_out = c_flag_;
} else {
uint32_t uresult = static_cast<uint32_t>(result);
uresult >>= (shift_amount - 1);
*carry_out = (uresult & 1) == 1;
uresult >>= 1;
result = static_cast<int32_t>(uresult);
}
break;
}
case ROR: {
UNIMPLEMENTED();
break;
}
default: {
UNREACHABLE();
break;
}
}
} else {
// by register
Register rs = instr->RsField();
shift_amount = get_register(rs) &0xff;
switch (shift) {
case ASR: {
if (shift_amount == 0) {
*carry_out = c_flag_;
} else if (shift_amount < 32) {
result >>= (shift_amount - 1);
*carry_out = (result & 1) == 1;
result >>= 1;
} else {
ASSERT(shift_amount >= 32);
if (result < 0) {
*carry_out = true;
result = 0xffffffff;
} else {
*carry_out = false;
result = 0;
}
}
break;
}
case LSL: {
if (shift_amount == 0) {
*carry_out = c_flag_;
} else if (shift_amount < 32) {
result <<= (shift_amount - 1);
*carry_out = (result < 0);
result <<= 1;
} else if (shift_amount == 32) {
*carry_out = (result & 1) == 1;
result = 0;
} else {
ASSERT(shift_amount > 32);
*carry_out = false;
result = 0;
}
break;
}
case LSR: {
if (shift_amount == 0) {
*carry_out = c_flag_;
} else if (shift_amount < 32) {
uint32_t uresult = static_cast<uint32_t>(result);
uresult >>= (shift_amount - 1);
*carry_out = (uresult & 1) == 1;
uresult >>= 1;
result = static_cast<int32_t>(uresult);
} else if (shift_amount == 32) {
*carry_out = (result < 0);
result = 0;
} else {
*carry_out = false;
result = 0;
}
break;
}
case ROR: {
UNIMPLEMENTED();
break;
}
default: {
UNREACHABLE();
break;
}
}
}
return result;
}
// Addressing Mode 1 - Data-processing operands:
// Get the value based on the shifter_operand with immediate.
int32_t Simulator::GetImm(Instr* instr, bool* carry_out) {
int rotate = instr->RotateField() * 2;
int immed8 = instr->Immed8Field();
int imm = (immed8 >> rotate) | (immed8 << (32 - rotate));
*carry_out = (rotate == 0) ? c_flag_ : (imm < 0);
return imm;
}
static int count_bits(int bit_vector) {
int count = 0;
while (bit_vector != 0) {
if ((bit_vector & 1) != 0) {
count++;
}
bit_vector >>= 1;
}
return count;
}
// Addressing Mode 4 - Load and Store Multiple
void Simulator::HandleRList(Instr* instr, bool load) {
Register rn = instr->RnField();
int32_t rn_val = get_register(rn);
int rlist = instr->RlistField();
int num_regs = count_bits(rlist);
uword address = 0;
uword end_address = 0;
switch (instr->PUField()) {
case 0: {
// Print("da");
address = rn_val - (num_regs * 4) + 4;
end_address = rn_val + 4;
rn_val = rn_val - (num_regs * 4);
break;
}
case 1: {
// Print("ia");
address = rn_val;
end_address = rn_val + (num_regs * 4);
rn_val = rn_val + (num_regs * 4);
break;
}
case 2: {
// Print("db");
address = rn_val - (num_regs * 4);
end_address = rn_val;
rn_val = address;
break;
}
case 3: {
// Print("ib");
address = rn_val + 4;
end_address = rn_val + (num_regs * 4) + 4;
rn_val = rn_val + (num_regs * 4);
break;
}
default: {
UNREACHABLE();
break;
}
}
if (IsIllegalAddress(address)) {
HandleIllegalAccess(address, instr);
} else {
if (instr->HasW()) {
set_register(rn, rn_val);
}
int reg = 0;
while (rlist != 0) {
if ((rlist & 1) != 0) {
if (load) {
set_register(static_cast<Register>(reg), ReadW(address, instr));
} else {
WriteW(address, get_register(static_cast<Register>(reg)), instr);
}
address += 4;
}
reg++;
rlist >>= 1;
}
ASSERT(end_address == address);
}
}
// Calls into the Dart runtime are based on this simple interface.
typedef void (*SimulatorRuntimeCall)(NativeArguments arguments);
static void PrintExternalCallTrace(intptr_t external,
NativeArguments arguments) {
// TODO(regis): Do a reverse lookup on this address and print the symbol.
UNIMPLEMENTED();
}
void Simulator::SupervisorCall(Instr* instr) {
int svc = instr->SvcField();
switch (svc) {
case kRedirectionSvcCode: {
SimulatorSetjmpBuffer buffer(this);
if (!setjmp(buffer.buffer_)) {
NativeArguments arguments;
ASSERT(sizeof(NativeArguments) == 4*kWordSize);
arguments.isolate_ = reinterpret_cast<Isolate*>(get_register(R0));
arguments.argc_tag_ = get_register(R1);
arguments.argv_ = reinterpret_cast<RawObject*(*)[]>(get_register(R2));
arguments.retval_ = reinterpret_cast<RawObject**>(get_register(R3));
int32_t saved_lr = get_register(LR);
Redirection* redirection = Redirection::FromSvcInstruction(instr);
intptr_t external =
reinterpret_cast<intptr_t>(redirection->external_function());
SimulatorRuntimeCall target =
reinterpret_cast<SimulatorRuntimeCall>(external);
if (FLAG_trace_sim) {
PrintExternalCallTrace(external, arguments);
}
target(arguments);
// Zap caller-saved registers, since the actual runtime call could have
// used them.
set_register(R2, icount_);
set_register(R3, icount_);
set_register(IP, icount_);
set_register(LR, icount_);
float zap_fvalue = static_cast<float>(icount_);
for (int i = S0; i <= S15; i++) {
set_sregister(static_cast<SRegister>(i), zap_fvalue);
}
#ifdef VFPv3_D32
double zap_dvalue = static_cast<double>(icount_);
for (int i = D16; i <= D31; i++) {
set_dregister(static_cast<DRegister>(i), zap_dvalue);
}
#endif // VFPv3_D32
// Zap result register pair R0:R1 and return.
set_register(R0, icount_);
set_register(R1, icount_);
set_pc(saved_lr);
}
break;
}
case kBreakpointSvcCode: {
SimulatorDebugger dbg(this);
dbg.Stop(instr, "breakpoint");
break;
}
case kStopMessageSvcCode: {
SimulatorDebugger dbg(this);
const char* message = *reinterpret_cast<const char**>(
reinterpret_cast<intptr_t>(instr) - Instr::kInstrSize);
set_pc(get_pc() + Instr::kInstrSize);
dbg.Stop(instr, message);
break;
}
case kWordSpillMarkerSvcCode: {
static StatsCounter counter_spill_w("Simulated word spills");
counter_spill_w.Increment();
break;
}
case kDWordSpillMarkerSvcCode: {
static StatsCounter counter_spill_d("Simulated double word spills");
counter_spill_d.Increment();
break;
}
default: {
UNREACHABLE();
break;
}
}
}
// Handle execution based on instruction types.
// Instruction types 0 and 1 are both rolled into one function because they
// only differ in the handling of the shifter_operand.
void Simulator::DecodeType01(Instr* instr) {
if (!instr->IsDataProcessing()) {
// miscellaneous, multiply, sync primitives, extra loads and stores.
if (instr->IsMiscellaneous()) {
switch (instr->Bits(4, 3)) {
case 1: {
ASSERT(instr->Bits(21, 2) == 0x3);
// Format(instr, "clz'cond 'rd, 'rm");
Register rm = instr->RmField();
Register rd = instr->RdField();
int32_t rm_val = get_register(rm);
int32_t rd_val = 0;
if (rm_val != 0) {
while (rm_val > 0) {
rd_val++;
rm_val <<= 1;
}
} else {
rd_val = 32;
}
set_register(rd, rd_val);
break;
}
case 3: {
ASSERT(instr->Bits(21, 2) == 0x1);
// Format(instr, "blx'cond 'rm");
Register rm = instr->RmField();
int32_t rm_val = get_register(rm);
intptr_t pc = get_pc();
set_register(LR, pc + Instr::kInstrSize);
set_pc(rm_val);
break;
}
case 7: {
if (instr->Bits(21, 2) == 0x1) {
// Format(instr, "bkpt #'imm12_4");
SimulatorDebugger dbg(this);
set_pc(get_pc() + Instr::kInstrSize);
char buffer[32];
snprintf(buffer, sizeof(buffer), "bkpt #0x%x", instr->BkptField());
dbg.Stop(instr, buffer);
} else {
// Format(instr, "smc'cond");
UNIMPLEMENTED();
}
break;
}
default: {
UNIMPLEMENTED();
break;
}
}
} else if (instr->IsMultiplyOrSyncPrimitive()) {
if (instr->Bit(24) == 0) {
// multiply instructions.
Register rn = instr->RnField();
Register rd = instr->RdField();
Register rs = instr->RsField();
Register rm = instr->RmField();
int32_t rm_val = get_register(rm);
int32_t rs_val = get_register(rs);
int32_t rd_val = 0;
switch (instr->Bits(21, 3)) {
case 1:
// Registers rd, rn, rm, ra are encoded as rn, rm, rs, rd.
// Format(instr, "mla'cond's 'rn, 'rm, 'rs, 'rd");
case 3: {
// Registers rd, rn, rm, ra are encoded as rn, rm, rs, rd.
// Format(instr, "mls'cond's 'rn, 'rm, 'rs, 'rd");
rd_val = get_register(rd);
// fall through
}
case 0: {
// Registers rd, rn, rm are encoded as rn, rm, rs.
// Format(instr, "mul'cond's 'rn, 'rm, 'rs");
int32_t alu_out = rm_val * rs_val;
if (instr->Bits(21, 3) == 3) { // mls
alu_out = -alu_out;
}
alu_out += rd_val;
set_register(rn, alu_out);
if (instr->HasS()) {
SetNZFlags(alu_out);
}
break;
}
case 4: {
// Registers rd_lo, rd_hi, rn, rm are encoded as rd, rn, rm, rs.
// Format(instr, "umull'cond's 'rd, 'rn, 'rm, 'rs");
uint64_t left_op = static_cast<uint32_t>(rm_val);
uint64_t right_op = static_cast<uint32_t>(rs_val);
uint64_t result = left_op * right_op;
int32_t hi_res = Utils::High32Bits(result);
int32_t lo_res = Utils::Low32Bits(result);
set_register(rd, lo_res);
set_register(rn, hi_res);
if (instr->HasS()) {
if (lo_res != 0) {
// Collapse bits 0..31 into bit 32 so that 32-bit Z check works.
hi_res |= 1;
}
ASSERT((result == 0) == (hi_res == 0)); // Z bit
ASSERT(((result & (1LL << 63)) != 0) == (hi_res < 0)); // N bit
SetNZFlags(hi_res);
}
break;
}
default: {
UNIMPLEMENTED();
break;
}
}
} else {
// synchronization primitives
Register rd = instr->RdField();
Register rn = instr->RnField();
uword addr = get_register(rn);
switch (instr->Bits(20, 4)) {
case 8: {
// Format(instr, "strex'cond 'rd, 'rm, ['rn]");
if (IsIllegalAddress(addr)) {
HandleIllegalAccess(addr, instr);
} else {
Register rm = instr->RmField();
set_register(rd, WriteExclusiveW(addr, get_register(rm), instr));
}
break;
}
case 9: {
// Format(instr, "ldrex'cond 'rd, ['rn]");
if (IsIllegalAddress(addr)) {
HandleIllegalAccess(addr, instr);
} else {
set_register(rd, ReadExclusiveW(addr, instr));
}
break;
}
default: {
UNIMPLEMENTED();
break;
}
}
}
} else if (instr->Bit(25) == 1) {
// 16-bit immediate loads, msr (immediate), and hints
switch (instr->Bits(20, 5)) {
case 16:
case 20: {
uint16_t imm16 = instr->MovwField();
Register rd = instr->RdField();
if (instr->Bit(22) == 0) {
// Format(instr, "movw'cond 'rd, #'imm4_12");
set_register(rd, imm16);
} else {
// Format(instr, "movt'cond 'rd, #'imm4_12");
set_register(rd, (get_register(rd) & 0xffff) | (imm16 << 16));
}
break;
}
case 18: {
if ((instr->Bits(16, 4) == 0) && (instr->Bits(0, 8) == 0)) {
// Format(instr, "nop'cond");
} else {
UNIMPLEMENTED();
}
break;
}
default: {
UNIMPLEMENTED();
break;
}
}
} else {
// extra load/store instructions
Register rd = instr->RdField();
Register rn = instr->RnField();
int32_t rn_val = get_register(rn);
uword addr = 0;
bool write_back = false;
if (instr->Bit(22) == 0) {
Register rm = instr->RmField();
int32_t rm_val = get_register(rm);
switch (instr->PUField()) {
case 0: {
// Format(instr, "'memop'cond'x 'rd2, ['rn], -'rm");
ASSERT(!instr->HasW());
addr = rn_val;
rn_val -= rm_val;
write_back = true;
break;
}
case 1: {
// Format(instr, "'memop'cond'x 'rd2, ['rn], +'rm");
ASSERT(!instr->HasW());
addr = rn_val;
rn_val += rm_val;
write_back = true;
break;
}
case 2: {
// Format(instr, "'memop'cond'x 'rd2, ['rn, -'rm]'w");
rn_val -= rm_val;
addr = rn_val;
write_back = instr->HasW();
break;
}
case 3: {
// Format(instr, "'memop'cond'x 'rd2, ['rn, +'rm]'w");
rn_val += rm_val;
addr = rn_val;
write_back = instr->HasW();
break;
}
default: {
// The PU field is a 2-bit field.
UNREACHABLE();
break;
}
}
} else {
int32_t imm_val = (instr->ImmedHField() << 4) | instr->ImmedLField();
switch (instr->PUField()) {
case 0: {
// Format(instr, "'memop'cond'x 'rd2, ['rn], #-'off8");
ASSERT(!instr->HasW());
addr = rn_val;
rn_val -= imm_val;
write_back = true;
break;
}
case 1: {
// Format(instr, "'memop'cond'x 'rd2, ['rn], #+'off8");
ASSERT(!instr->HasW());
addr = rn_val;
rn_val += imm_val;
write_back = true;
break;
}
case 2: {
// Format(instr, "'memop'cond'x 'rd2, ['rn, #-'off8]'w");
rn_val -= imm_val;
addr = rn_val;
write_back = instr->HasW();
break;
}
case 3: {
// Format(instr, "'memop'cond'x 'rd2, ['rn, #+'off8]'w");
rn_val += imm_val;
addr = rn_val;
write_back = instr->HasW();
break;
}
default: {
// The PU field is a 2-bit field.
UNREACHABLE();
break;
}
}
}
if (IsIllegalAddress(addr)) {
HandleIllegalAccess(addr, instr);
} else {
if (write_back) {
set_register(rn, rn_val);
}
if (!instr->HasSign()) {
if (instr->HasL()) {
uint16_t val = ReadHU(addr, instr);
set_register(rd, val);
} else {
uint16_t val = get_register(rd);
WriteH(addr, val, instr);
}
} else if (instr->HasL()) {
if (instr->HasH()) {
int16_t val = ReadH(addr, instr);
set_register(rd, val);
} else {
int8_t val = ReadB(addr);
set_register(rd, val);
}
} else if ((rd & 1) == 0) {
Register rd1 = static_cast<Register>(rd | 1);
ASSERT(rd1 < kNumberOfCpuRegisters);
if (instr->HasH()) {
int32_t val_low = get_register(rd);
int32_t val_high = get_register(rd1);
WriteW(addr, val_low, instr);
WriteW(addr + 4, val_high, instr);
} else {
int32_t val_low = ReadW(addr, instr);
int32_t val_high = ReadW(addr + 4, instr);
set_register(rd, val_low);
set_register(rd1, val_high);
}
} else {
UNIMPLEMENTED();
}
}
}
} else {
Register rd = instr->RdField();
Register rn = instr->RnField();
int32_t rn_val = get_register(rn);
int32_t shifter_operand = 0;
bool shifter_carry_out = 0;
if (instr->TypeField() == 0) {
shifter_operand = GetShiftRm(instr, &shifter_carry_out);
} else {
ASSERT(instr->TypeField() == 1);
shifter_operand = GetImm(instr, &shifter_carry_out);
}
int32_t alu_out;
switch (instr->OpcodeField()) {
case AND: {
// Format(instr, "and'cond's 'rd, 'rn, 'shift_rm");
// Format(instr, "and'cond's 'rd, 'rn, 'imm");
alu_out = rn_val & shifter_operand;
set_register(rd, alu_out);
if (instr->HasS()) {
SetNZFlags(alu_out);
SetCFlag(shifter_carry_out);
}
break;
}
case EOR: {
// Format(instr, "eor'cond's 'rd, 'rn, 'shift_rm");
// Format(instr, "eor'cond's 'rd, 'rn, 'imm");
alu_out = rn_val ^ shifter_operand;
set_register(rd, alu_out);
if (instr->HasS()) {
SetNZFlags(alu_out);
SetCFlag(shifter_carry_out);
}
break;
}
case SUB: {
// Format(instr, "sub'cond's 'rd, 'rn, 'shift_rm");
// Format(instr, "sub'cond's 'rd, 'rn, 'imm");
alu_out = rn_val - shifter_operand;
set_register(rd, alu_out);
if (instr->HasS()) {
SetNZFlags(alu_out);
SetCFlag(!BorrowFrom(rn_val, shifter_operand));
SetVFlag(OverflowFrom(alu_out, rn_val, shifter_operand, false));
}
break;
}
case RSB: {
// Format(instr, "rsb'cond's 'rd, 'rn, 'shift_rm");
// Format(instr, "rsb'cond's 'rd, 'rn, 'imm");
alu_out = shifter_operand - rn_val;
set_register(rd, alu_out);
if (instr->HasS()) {
SetNZFlags(alu_out);
SetCFlag(!BorrowFrom(shifter_operand, rn_val));
SetVFlag(OverflowFrom(alu_out, shifter_operand, rn_val, false));
}
break;
}
case ADD: {
// Format(instr, "add'cond's 'rd, 'rn, 'shift_rm");
// Format(instr, "add'cond's 'rd, 'rn, 'imm");
alu_out = rn_val + shifter_operand;
set_register(rd, alu_out);
if (instr->HasS()) {
SetNZFlags(alu_out);
SetCFlag(CarryFrom(rn_val, shifter_operand));
SetVFlag(OverflowFrom(alu_out, rn_val, shifter_operand, true));
}
break;
}
case ADC: {
// Format(instr, "adc'cond's 'rd, 'rn, 'shift_rm");
// Format(instr, "adc'cond's 'rd, 'rn, 'imm");
alu_out = rn_val + shifter_operand + (c_flag_ ? 1 : 0);
set_register(rd, alu_out);
if (instr->HasS()) {
SetNZFlags(alu_out);
SetCFlag(CarryFrom(rn_val, shifter_operand));
SetVFlag(OverflowFrom(alu_out, rn_val, shifter_operand, true));
}
break;
}
case SBC: {
// Format(instr, "sbc'cond's 'rd, 'rn, 'shift_rm");
// Format(instr, "sbc'cond's 'rd, 'rn, 'imm");
alu_out = rn_val - shifter_operand - (!c_flag_ ? 1 : 0);
set_register(rd, alu_out);
if (instr->HasS()) {
SetNZFlags(alu_out);
SetCFlag(!BorrowFrom(rn_val, shifter_operand));
SetVFlag(OverflowFrom(alu_out, rn_val, shifter_operand, false));
}
break;
}
case RSC: {
// Format(instr, "rsc'cond's 'rd, 'rn, 'shift_rm");
// Format(instr, "rsc'cond's 'rd, 'rn, 'imm");
alu_out = shifter_operand - rn_val - (!c_flag_ ? 1 : 0);
set_register(rd, alu_out);
if (instr->HasS()) {
SetNZFlags(alu_out);
SetCFlag(!BorrowFrom(shifter_operand, rn_val));
SetVFlag(OverflowFrom(alu_out, shifter_operand, rn_val, false));
}
break;
}
case TST: {
if (instr->HasS()) {
// Format(instr, "tst'cond 'rn, 'shift_rm");
// Format(instr, "tst'cond 'rn, 'imm");
alu_out = rn_val & shifter_operand;
SetNZFlags(alu_out);
SetCFlag(shifter_carry_out);
} else {
UNIMPLEMENTED();
}
break;
}
case TEQ: {
if (instr->HasS()) {
// Format(instr, "teq'cond 'rn, 'shift_rm");
// Format(instr, "teq'cond 'rn, 'imm");
alu_out = rn_val ^ shifter_operand;
SetNZFlags(alu_out);
SetCFlag(shifter_carry_out);
} else {
UNIMPLEMENTED();
}
break;
}
case CMP: {
if (instr->HasS()) {
// Format(instr, "cmp'cond 'rn, 'shift_rm");
// Format(instr, "cmp'cond 'rn, 'imm");
alu_out = rn_val - shifter_operand;
SetNZFlags(alu_out);
SetCFlag(!BorrowFrom(rn_val, shifter_operand));
SetVFlag(OverflowFrom(alu_out, rn_val, shifter_operand, false));
} else {
UNIMPLEMENTED();
}
break;
}
case CMN: {
if (instr->HasS()) {
// Format(instr, "cmn'cond 'rn, 'shift_rm");
// Format(instr, "cmn'cond 'rn, 'imm");
alu_out = rn_val + shifter_operand;
SetNZFlags(alu_out);
SetCFlag(CarryFrom(rn_val, shifter_operand));
SetVFlag(OverflowFrom(alu_out, rn_val, shifter_operand, true));
} else {
UNIMPLEMENTED();
}
break;
}
case ORR: {
// Format(instr, "orr'cond's 'rd, 'rn, 'shift_rm");
// Format(instr, "orr'cond's 'rd, 'rn, 'imm");
alu_out = rn_val | shifter_operand;
set_register(rd, alu_out);
if (instr->HasS()) {
SetNZFlags(alu_out);
SetCFlag(shifter_carry_out);
}
break;
}
case MOV: {
// Format(instr, "mov'cond's 'rd, 'shift_rm");
// Format(instr, "mov'cond's 'rd, 'imm");
alu_out = shifter_operand;
set_register(rd, alu_out);
if (instr->HasS()) {
SetNZFlags(alu_out);
SetCFlag(shifter_carry_out);
}
break;
}
case BIC: {
// Format(instr, "bic'cond's 'rd, 'rn, 'shift_rm");
// Format(instr, "bic'cond's 'rd, 'rn, 'imm");
alu_out = rn_val & ~shifter_operand;
set_register(rd, alu_out);
if (instr->HasS()) {
SetNZFlags(alu_out);
SetCFlag(shifter_carry_out);
}
break;
}
case MVN: {
// Format(instr, "mvn'cond's 'rd, 'shift_rm");
// Format(instr, "mvn'cond's 'rd, 'imm");
alu_out = ~shifter_operand;
set_register(rd, alu_out);
if (instr->HasS()) {
SetNZFlags(alu_out);
SetCFlag(shifter_carry_out);
}
break;
}
default: {
UNREACHABLE();
break;
}
}
}
}
void Simulator::DecodeType2(Instr* instr) {
Register rd = instr->RdField();
Register rn = instr->RnField();
int32_t rn_val = get_register(rn);
int32_t im_val = instr->Offset12Field();
uword addr = 0;
bool write_back = false;
switch (instr->PUField()) {
case 0: {
// Format(instr, "'memop'cond'b 'rd, ['rn], #-'off12");
ASSERT(!instr->HasW());
addr = rn_val;
rn_val -= im_val;
write_back = true;
break;
}
case 1: {
// Format(instr, "'memop'cond'b 'rd, ['rn], #+'off12");
ASSERT(!instr->HasW());
addr = rn_val;
rn_val += im_val;
write_back = true;
break;
}
case 2: {
// Format(instr, "'memop'cond'b 'rd, ['rn, #-'off12]'w");
rn_val -= im_val;
addr = rn_val;
write_back = instr->HasW();
break;
}
case 3: {
// Format(instr, "'memop'cond'b 'rd, ['rn, #+'off12]'w");
rn_val += im_val;
addr = rn_val;
write_back = instr->HasW();
break;
}
default: {
UNREACHABLE();
break;
}
}
if (IsIllegalAddress(addr)) {
HandleIllegalAccess(addr, instr);
} else {
if (write_back) {
set_register(rn, rn_val);
}
if (instr->HasB()) {
if (instr->HasL()) {
unsigned char val = ReadBU(addr);
set_register(rd, val);
} else {
unsigned char val = get_register(rd);
WriteB(addr, val);
}
} else {
if (instr->HasL()) {
set_register(rd, ReadW(addr, instr));
} else {
WriteW(addr, get_register(rd), instr);
}
}
}
}
void Simulator::DecodeType3(Instr* instr) {
Register rd = instr->RdField();
Register rn = instr->RnField();
int32_t rn_val = get_register(rn);
bool shifter_carry_out = 0;
int32_t shifter_operand = GetShiftRm(instr, &shifter_carry_out);
uword addr = 0;
bool write_back = false;
switch (instr->PUField()) {
case 0: {
// Format(instr, "'memop'cond'b 'rd, ['rn], -'shift_rm");
ASSERT(!instr->HasW());
addr = rn_val;
rn_val -= shifter_operand;
write_back = true;
break;
}
case 1: {
// Format(instr, "'memop'cond'b 'rd, ['rn], +'shift_rm");
ASSERT(!instr->HasW());
addr = rn_val;
rn_val += shifter_operand;
write_back = true;
break;
}
case 2: {
// Format(instr, "'memop'cond'b 'rd, ['rn, -'shift_rm]'w");
rn_val -= shifter_operand;
addr = rn_val;
write_back = instr->HasW();
break;
}
case 3: {
// Format(instr, "'memop'cond'b 'rd, ['rn, +'shift_rm]'w");
rn_val += shifter_operand;
addr = rn_val;
write_back = instr->HasW();
break;
}
default: {
UNREACHABLE();
break;
}
}
if (IsIllegalAddress(addr)) {
HandleIllegalAccess(addr, instr);
} else {
if (write_back) {
set_register(rn, rn_val);
}
if (instr->HasB()) {
if (instr->HasL()) {
unsigned char val = ReadBU(addr);
set_register(rd, val);
} else {
unsigned char val = get_register(rd);
WriteB(addr, val);
}
} else {
if (instr->HasL()) {
set_register(rd, ReadW(addr, instr));
} else {
WriteW(addr, get_register(rd), instr);
}
}
}
}
void Simulator::DecodeType4(Instr* instr) {
ASSERT(instr->Bit(22) == 0); // only allowed to be set in privileged mode
if (instr->HasL()) {
// Format(instr, "ldm'cond'pu 'rn'w, 'rlist");
HandleRList(instr, true);
} else {
// Format(instr, "stm'cond'pu 'rn'w, 'rlist");
HandleRList(instr, false);
}
}
void Simulator::DecodeType5(Instr* instr) {
// Format(instr, "b'l'cond 'target");
int off = (instr->SImmed24Field() << 2) + 8;
intptr_t pc = get_pc();
if (instr->HasLink()) {
set_register(LR, pc + Instr::kInstrSize);
}
set_pc(pc+off);
}
void Simulator::DecodeType6(Instr* instr) {
if (instr->IsVFPDoubleTransfer()) {
Register rd = instr->RdField();
Register rn = instr->RnField();
if (instr->Bit(8) == 0) {
SRegister sm = instr->SmField();
SRegister sm1 = static_cast<SRegister>(sm + 1);
ASSERT(sm1 < kNumberOfSRegisters);
if (instr->Bit(20) == 1) {
// Format(instr, "vmovrrs'cond 'rd, 'rn, {'sm', 'sm1}");
set_register(rd, bit_cast<int32_t, float>(get_sregister(sm)));
set_register(rn, bit_cast<int32_t, float>(get_sregister(sm1)));
} else {
// Format(instr, "vmovsrr'cond {'sm, 'sm1}, 'rd', 'rn");
set_sregister(sm, bit_cast<float, int32_t>(get_register(rd)));
set_sregister(sm1, bit_cast<float, int32_t>(get_register(rn)));
}
} else {
DRegister dm = instr->DmField();
if (instr->Bit(20) == 1) {
// Format(instr, "vmovrrd'cond 'rd, 'rn, 'dm");
int64_t dm_val = bit_cast<int64_t, double>(get_dregister(dm));
set_register(rd, Utils::Low32Bits(dm_val));
set_register(rn, Utils::High32Bits(dm_val));
} else {
// Format(instr, "vmovdrr'cond 'dm, 'rd, 'rn");
int64_t dm_val = Utils::LowHighTo64Bits(get_register(rd),
get_register(rn));
set_dregister(dm, bit_cast<double, int64_t>(dm_val));
}
}
} else if (instr-> IsVFPLoadStore()) {
Register rn = instr->RnField();
int32_t addr = get_register(rn);
int32_t imm_val = instr->Bits(0, 8) << 2;
if (instr->Bit(23) == 1) {
addr += imm_val;
} else {
addr -= imm_val;
}
if (IsIllegalAddress(addr)) {
HandleIllegalAccess(addr, instr);
} else {
if (instr->Bit(8) == 0) {
SRegister sd = instr->SdField();
if (instr->Bit(20) == 1) { // vldrs
// Format(instr, "vldrs'cond 'sd, ['rn, #+'off10]");
// Format(instr, "vldrs'cond 'sd, ['rn, #-'off10]");
set_sregister(sd, bit_cast<float, int32_t>(ReadW(addr, instr)));
} else { // vstrs
// Format(instr, "vstrs'cond 'sd, ['rn, #+'off10]");
// Format(instr, "vstrs'cond 'sd, ['rn, #-'off10]");
WriteW(addr, bit_cast<int32_t, float>(get_sregister(sd)), instr);
}
} else {
DRegister dd = instr->DdField();
if (instr->Bit(20) == 1) { // vldrd
// Format(instr, "vldrd'cond 'dd, ['rn, #+'off10]");
// Format(instr, "vldrd'cond 'dd, ['rn, #-'off10]");
int64_t dd_val = Utils::LowHighTo64Bits(ReadW(addr, instr),
ReadW(addr + 4, instr));
set_dregister(dd, bit_cast<double, int64_t>(dd_val));
} else { // vstrd
// Format(instr, "vstrd'cond 'dd, ['rn, #+'off10]");
// Format(instr, "vstrd'cond 'dd, ['rn, #-'off10]");
int64_t dd_val = bit_cast<int64_t, double>(get_dregister(dd));
WriteW(addr, Utils::Low32Bits(dd_val), instr);
WriteW(addr + 4, Utils::High32Bits(dd_val), instr);
}
}
}
} else {
UNIMPLEMENTED();
}
}
void Simulator::DecodeType7(Instr* instr) {
if (instr->Bit(24) == 1) {
// Format(instr, "svc #'svc");
SupervisorCall(instr);
} else if (instr->IsVFPDataProcessingOrSingleTransfer()) {
if (instr->Bit(4) == 0) {
// VFP Data Processing
SRegister sd;
SRegister sn;
SRegister sm;
DRegister dd;
DRegister dn;
DRegister dm;
if (instr->Bit(8) == 0) {
sd = instr->SdField();
sn = instr->SnField();
sm = instr->SmField();
dd = kNoDRegister;
dn = kNoDRegister;
dm = kNoDRegister;
} else {
sd = kNoSRegister;
sn = kNoSRegister;
sm = kNoSRegister;
dd = instr->DdField();
dn = instr->DnField();
dm = instr->DmField();
}
switch (instr->Bits(20, 4) & 0xb) {
case 1: // vnmla, vnmls, vnmul
default: {
UNIMPLEMENTED();
break;
}
case 0: { // vmla, vmls floating-point
if (instr->Bit(8) == 0) {
float addend = get_sregister(sn) * get_sregister(sm);
float sd_val = get_sregister(sd);
if (instr->Bit(6) == 0) {
// Format(instr, "vmlas'cond 'sd, 'sn, 'sm");
} else {
// Format(instr, "vmlss'cond 'sd, 'sn, 'sm");
addend = -addend;
}
set_sregister(sd, sd_val + addend);
} else {
double addend = get_dregister(dn) * get_dregister(dm);
double dd_val = get_dregister(dd);
if (instr->Bit(6) == 0) {
// Format(instr, "vmlad'cond 'dd, 'dn, 'dm");
} else {
// Format(instr, "vmlsd'cond 'dd, 'dn, 'dm");
addend = -addend;
}
set_dregister(dd, dd_val + addend);
}
break;
}
case 2: { // vmul
if (instr->Bit(8) == 0) {
// Format(instr, "vmuls'cond 'sd, 'sn, 'sm");
set_sregister(sd, get_sregister(sn) * get_sregister(sm));
} else {
// Format(instr, "vmuld'cond 'dd, 'dn, 'dm");
set_dregister(dd, get_dregister(dn) * get_dregister(dm));
}
break;
}
case 8: { // vdiv
if (instr->Bit(8) == 0) {
// Format(instr, "vdivs'cond 'sd, 'sn, 'sm");
set_sregister(sd, get_sregister(sn) / get_sregister(sm));
} else {
// Format(instr, "vdivd'cond 'dd, 'dn, 'dm");
set_dregister(dd, get_dregister(dn) / get_dregister(dm));
}
break;
}
case 3: { // vadd, vsub floating-point
if (instr->Bit(8) == 0) {
if (instr->Bit(6) == 0) {
// Format(instr, "vadds'cond 'sd, 'sn, 'sm");
set_sregister(sd, get_sregister(sn) + get_sregister(sm));
} else {
// Format(instr, "vsubs'cond 'sd, 'sn, 'sm");
set_sregister(sd, get_sregister(sn) - get_sregister(sm));
}
} else {
if (instr->Bit(6) == 0) {
// Format(instr, "vaddd'cond 'dd, 'dn, 'dm");
set_dregister(dd, get_dregister(dn) + get_dregister(dm));
} else {
// Format(instr, "vsubd'cond 'dd, 'dn, 'dm");
set_dregister(dd, get_dregister(dn) - get_dregister(dm));
}
}
break;
}
case 0xb: { // Other VFP data-processing instructions
if (instr->Bit(6) == 0) { // vmov immediate
if (instr->Bit(8) == 0) {
// Format(instr, "vmovs'cond 'sd, #'immf");
set_sregister(sd, instr->ImmFloatField());
} else {
// Format(instr, "vmovd'cond 'dd, #'immd");
set_dregister(dd, instr->ImmDoubleField());
}
break;
}
switch (instr->Bits(16, 4)) {
case 0: { // vmov immediate, vmov register, vabs
switch (instr->Bits(6, 2)) {
case 1: { // vmov register
if (instr->Bit(8) == 0) {
// Format(instr, "vmovs'cond 'sd, 'sm");
set_sregister(sd, get_sregister(sm));
} else {
// Format(instr, "vmovd'cond 'dd, 'dm");
set_dregister(dd, get_dregister(dm));
}
break;
}
case 3: { // vabs
if (instr->Bit(8) == 0) {
// Format(instr, "vabss'cond 'sd, 'sm");
set_sregister(sd, fabsf(get_sregister(sm)));
} else {
// Format(instr, "vabsd'cond 'dd, 'dm");
set_dregister(dd, fabs(get_dregister(dm)));
}
break;
}
default: {
UNIMPLEMENTED();
break;
}
}
break;
}
case 1: { // vneg, vsqrt
switch (instr->Bits(6, 2)) {
case 1: { // vneg
if (instr->Bit(8) == 0) {
// Format(instr, "vnegs'cond 'sd, 'sm");
set_sregister(sd, -get_sregister(sm));
} else {
// Format(instr, "vnegd'cond 'dd, 'dm");
set_dregister(dd, -get_dregister(dm));
}
break;
}
case 3: { // vsqrt
if (instr->Bit(8) == 0) {
// Format(instr, "vsqrts'cond 'sd, 'sm");
set_sregister(sd, sqrtf(get_sregister(sm)));
} else {
// Format(instr, "vsqrtd'cond 'dd, 'dm");
set_dregister(dd, sqrt(get_dregister(dm)));
}
break;
}
default: {
UNIMPLEMENTED();
break;
}
}
break;
}
case 4: // vcmp, vcmpe
case 5: { // vcmp #0.0, vcmpe #0.0
if (instr->Bit(7) == 1) { // vcmpe
UNIMPLEMENTED();
} else {
fp_n_flag_ = false;
fp_z_flag_ = false;
fp_c_flag_ = false;
fp_v_flag_ = false;
if (instr->Bit(8) == 0) { // vcmps
float sd_val = get_sregister(sd);
float sm_val;
if (instr->Bit(16) == 0) {
// Format(instr, "vcmps'cond 'sd, 'sm");
sm_val = get_sregister(sm);
} else {
// Format(instr, "vcmps'cond 'sd, #0.0");
sm_val = 0.0f;
}
if (isnan(sd_val) || isnan(sm_val)) {
fp_c_flag_ = true;
fp_v_flag_ = true;
} else if (sd_val == sm_val) {
fp_z_flag_ = true;
fp_c_flag_ = true;
} else if (sd_val < sm_val) {
fp_n_flag_ = true;
} else {
fp_c_flag_ = true;
}
} else { // vcmpd
double dd_val = get_dregister(dd);
double dm_val;
if (instr->Bit(16) == 0) {
// Format(instr, "vcmpd'cond 'dd, 'dm");
dm_val = get_dregister(dm);
} else {
// Format(instr, "vcmpd'cond 'dd, #0.0");
dm_val = 0.0;
}
if (isnan(dd_val) || isnan(dm_val)) {
fp_c_flag_ = true;
fp_v_flag_ = true;
} else if (dd_val == dm_val) {
fp_z_flag_ = true;
fp_c_flag_ = true;
} else if (dd_val < dm_val) {
fp_n_flag_ = true;
} else {
fp_c_flag_ = true;
}
}
}
break;
}
case 7: { // vcvt between double-precision and single-precision
if (instr->Bit(8) == 0) {
// Format(instr, "vcvtds'cond 'dd, 'sm");
dd = instr->DdField();
set_dregister(dd, static_cast<double>(get_sregister(sm)));
} else {
// Format(instr, "vcvtsd'cond 'sd, 'dm");
sd = instr->SdField();
set_sregister(sd, static_cast<float>(get_dregister(dm)));
}
break;
}
case 8: { // vcvt, vcvtr between floating-point and integer
sm = instr->SmField();
float sm_val = get_sregister(sm);
uint32_t ud_val = 0;
int32_t id_val = 0;
if (instr->Bit(7) == 0) { // vcvtsu, vcvtdu
ud_val = bit_cast<uint32_t, float>(sm_val);
} else { // vcvtsi, vcvtdi
id_val = bit_cast<int32_t, float>(sm_val);
}
if (instr->Bit(8) == 0) {
float sd_val;
if (instr->Bit(7) == 0) {
// Format(instr, "vcvtsu'cond 'sd, 'sm");
sd_val = static_cast<float>(ud_val);
} else {
// Format(instr, "vcvtsi'cond 'sd, 'sm");
sd_val = static_cast<float>(id_val);
}
set_sregister(sd, sd_val);
} else {
double dd_val;
if (instr->Bit(7) == 0) {
// Format(instr, "vcvtdu'cond 'dd, 'sm");
dd_val = static_cast<double>(ud_val);
} else {
// Format(instr, "vcvtdi'cond 'dd, 'sm");
dd_val = static_cast<double>(id_val);
}
set_dregister(dd, dd_val);
}
break;
}
case 12:
case 13: { // vcvt, vcvtr between floating-point and integer
// We do not need to record exceptions in the FPSCR cumulative
// flags, because we do not use them.
if (instr->Bit(7) == 0) {
// We only support round-to-zero mode
UNIMPLEMENTED();
break;
}
int32_t id_val = 0;
uint32_t ud_val = 0;
if (instr->Bit(8) == 0) {
float sm_val = get_sregister(sm);
if (instr->Bit(16) == 0) {
// Format(instr, "vcvtus'cond 'sd, 'sm");
if (sm_val >= INT_MAX) {
ud_val = INT_MAX;
} else if (sm_val > 0.0) {
ud_val = static_cast<uint32_t>(sm_val);
}
} else {
// Format(instr, "vcvtis'cond 'sd, 'sm");
if (sm_val <= INT_MIN) {
id_val = INT_MIN;
} else if (sm_val >= INT_MAX) {
id_val = INT_MAX;
} else {
id_val = static_cast<int32_t>(sm_val);
}
ASSERT((id_val >= 0) || !(sm_val >= 0.0));
}
} else {
sd = instr->SdField();
double dm_val = get_dregister(dm);
if (instr->Bit(16) == 0) {
// Format(instr, "vcvtud'cond 'sd, 'dm");
if (dm_val >= INT_MAX) {
ud_val = INT_MAX;
} else if (dm_val > 0.0) {
ud_val = static_cast<uint32_t>(dm_val);
}
} else {
// Format(instr, "vcvtid'cond 'sd, 'dm");
if (dm_val <= INT_MIN) {
id_val = INT_MIN;
} else if (dm_val >= INT_MAX) {
id_val = INT_MAX;
} else {
id_val = static_cast<int32_t>(dm_val);
}
ASSERT((id_val >= 0) || !(dm_val >= 0.0));
}
}
float sd_val;
if (instr->Bit(16) == 0) {
sd_val = bit_cast<float, uint32_t>(ud_val);
} else {
sd_val = bit_cast<float, int32_t>(id_val);
}
set_sregister(sd, sd_val);
break;
}
case 2: // vcvtb, vcvtt
case 3: // vcvtb, vcvtt
case 9: // undefined
case 10: // vcvt between floating-point and fixed-point
case 11: // vcvt between floating-point and fixed-point
case 14: // vcvt between floating-point and fixed-point
case 15: // vcvt between floating-point and fixed-point
default: {
UNIMPLEMENTED();
break;
}
}
}
break;
}
} else {
// 8, 16, or 32-bit Transfer between ARM Core and VFP
if ((instr->Bits(21, 3) == 0) && (instr->Bit(8) == 0)) {
Register rd = instr->RdField();
SRegister sn = instr->SnField();
if (instr->Bit(20) == 0) {
// Format(instr, "vmovs'cond 'sn, 'rd");
set_sregister(sn, bit_cast<float, int32_t>(get_register(rd)));
} else {
// Format(instr, "vmovr'cond 'rd, 'sn");
set_register(rd, bit_cast<int32_t, float>(get_sregister(sn)));
}
} else if ((instr->Bits(20, 4) == 0xf) && (instr->Bit(8) == 0) &&
(instr->Bits(12, 4) == 0xf)) {
// Format(instr, "vmstat'cond");
n_flag_ = fp_n_flag_;
z_flag_ = fp_z_flag_;
c_flag_ = fp_c_flag_;
v_flag_ = fp_v_flag_;
} else {
UNIMPLEMENTED();
}
}
} else {
UNIMPLEMENTED();
}
}
// Executes the current instruction.
void Simulator::InstructionDecode(Instr* instr) {
pc_modified_ = false;
if (FLAG_trace_sim) {
const uword start = reinterpret_cast<uword>(instr);
const uword end = start + Instr::kInstrSize;
Disassembler::Disassemble(start, end);
}
if (instr->ConditionField() == kSpecialCondition) {
if (instr->InstructionBits() == static_cast<int32_t>(0xf57ff01f)) {
// Format(instr, "clrex");
ClearExclusive();
} else {
UNIMPLEMENTED();
}
} else if (ConditionallyExecute(instr)) {
switch (instr->TypeField()) {
case 0:
case 1: {
DecodeType01(instr);
break;
}
case 2: {
DecodeType2(instr);
break;
}
case 3: {
DecodeType3(instr);
break;
}
case 4: {
DecodeType4(instr);
break;
}
case 5: {
DecodeType5(instr);
break;
}
case 6: {
DecodeType6(instr);
break;
}
case 7: {
DecodeType7(instr);
break;
}
default: {
UNIMPLEMENTED();
break;
}
}
}
if (!pc_modified_) {
set_register(PC, reinterpret_cast<int32_t>(instr) + Instr::kInstrSize);
}
}
void Simulator::Execute() {
static StatsCounter counter_instructions("Simulated instructions");
// 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.
uword program_counter = get_pc();
if (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 != kEndSimulatingPC) {
Instr* instr = reinterpret_cast<Instr*>(program_counter);
icount_++;
counter_instructions.Increment();
if (IsIllegalAddress(program_counter)) {
HandleIllegalAccess(program_counter, instr);
} else {
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 instruction count.
while (program_counter != kEndSimulatingPC) {
Instr* instr = reinterpret_cast<Instr*>(program_counter);
icount_++;
counter_instructions.Increment();
if (icount_ == FLAG_stop_sim_at) {
SimulatorDebugger dbg(this);
dbg.Debug();
} else if (IsIllegalAddress(program_counter)) {
HandleIllegalAccess(program_counter, instr);
} else {
InstructionDecode(instr);
}
program_counter = get_pc();
}
}
}
int64_t Simulator::Call(int32_t entry,
int32_t parameter0,
int32_t parameter1,
int32_t parameter2,
int32_t parameter3,
int32_t parameter4) {
// Save the SP register before the call so we can restore it.
int32_t sp_before_call = get_register(SP);
// Setup parameters.
set_register(R0, parameter0);
set_register(R1, parameter1);
set_register(R2, parameter2);
set_register(R3, parameter3);
// Reserve room for one stack parameter.
int32_t stack_pointer = sp_before_call;
stack_pointer -= kWordSize;
// Make sure the activation frames are properly aligned.
static const int kFrameAlignment = OS::ActivationFrameAlignment();
if (kFrameAlignment > 0) {
stack_pointer = Utils::RoundDown(stack_pointer, kFrameAlignment);
}
// Write the fourth parameter to the stack and update register SP.
*reinterpret_cast<int32_t*>(stack_pointer) = parameter4;
set_register(SP, stack_pointer);
// Prepare to execute the code at entry.
set_register(PC, 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(LR, kEndSimulatingPC);
// 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 r4_val = get_register(R4);
int32_t r5_val = get_register(R5);
int32_t r6_val = get_register(R6);
int32_t r7_val = get_register(R7);
int32_t r8_val = get_register(R8);
int32_t r9_val = get_register(R9);
int32_t r10_val = get_register(R10);
int32_t r11_val = get_register(R11);
// 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(R4, callee_saved_value);
set_register(R5, callee_saved_value);
set_register(R6, callee_saved_value);
set_register(R7, callee_saved_value);
set_register(R8, callee_saved_value);
set_register(R9, callee_saved_value);
set_register(R10, callee_saved_value);
set_register(R11, callee_saved_value);
// Start the simulation
Execute();
// Check that the callee-saved registers have been preserved.
ASSERT(callee_saved_value == get_register(R4));
ASSERT(callee_saved_value == get_register(R5));
ASSERT(callee_saved_value == get_register(R6));
ASSERT(callee_saved_value == get_register(R7));
ASSERT(callee_saved_value == get_register(R8));
ASSERT(callee_saved_value == get_register(R9));
ASSERT(callee_saved_value == get_register(R10));
ASSERT(callee_saved_value == get_register(R11));
// Restore callee-saved registers with the original value.
set_register(R4, r4_val);
set_register(R5, r5_val);
set_register(R6, r6_val);
set_register(R7, r7_val);
set_register(R8, r8_val);
set_register(R9, r9_val);
set_register(R10, r10_val);
set_register(R11, r11_val);
// Restore the SP register and return R1:R0.
set_register(SP, sp_before_call);
return Utils::LowHighTo64Bits(get_register(R0), get_register(R1));
}
void Simulator::Longjmp(
int32_t pc, int32_t sp, int32_t fp, const Instance& object) {
set_register(SP, sp);
set_register(FP, fp);
set_register(PC, pc);
SimulatorSetjmpBuffer* buf = last_setjmp_buffer();
// Walk over all setjmp buffers (simulated --> C++ transitions)
// and try to find the setjmp associated with the stack pointer.
while (buf->link() != NULL && buf->link()->sp() <= sp) {
buf = buf->link();
}
ASSERT(buf != NULL);
// Clean up stack memory of C++ frames.
// TODO(regis): Revisit.
// isolate->PrepareForUnwinding(reinterpret_cast<uword>(buf));
// isolate->ChangeStateToGeneratedCode();
set_register(kExceptionObjectReg, bit_cast<int32_t>(object.raw()));
buf->Longjmp();
}
} // namespace dart
#endif // !defined(HOST_ARCH_ARM)
#endif // defined TARGET_ARCH_ARM
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