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ff6c4fe680
v8/src/arm/simulator-arm.cc
sgjesse@chromium.org ff6c4fe680 ARM: Special code for raising to the power of an integer 
When calculating Math.pow where the exponent is a smi use a simple loop to calculate the result.

Added support for the vmov instruction moving from one doubleword extension register to another.

Added some Math.pow tests which partially covers what is in the Sputnik tests.
Review URL: http://codereview.chromium.org/2804033

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4990 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2010-06-30 12:22:15 +00:00

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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 <math.h>
#include <cstdarg>
#include "v8.h"
#if defined(V8_TARGET_ARCH_ARM)
#include "disasm.h"
#include "assembler.h"
#include "arm/constants-arm.h"
#include "arm/simulator-arm.h"
#if !defined(__arm__)
// Only build the simulator if not compiling for real ARM hardware.
namespace assembler {
namespace arm {
using ::v8::internal::Object;
using ::v8::internal::PrintF;
using ::v8::internal::OS;
using ::v8::internal::ReadLine;
using ::v8::internal::DeleteArray;
// This macro provides a platform independent use of sscanf. The reason for
// SScanF not being implemented in a platform independent way 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 ARM
// code.
class Debugger {
public:
explicit Debugger(Simulator* sim);
~Debugger();
void Stop(Instr* instr);
void Debug();
private:
static const instr_t kBreakpointInstr =
((AL << 28) | (7 << 25) | (1 << 24) | break_point);
static const instr_t kNopInstr =
((AL << 28) | (13 << 21));
Simulator* sim_;
int32_t GetRegisterValue(int regnum);
bool GetValue(const char* desc, int32_t* value);
bool GetVFPSingleValue(const char* desc, float* value);
bool GetVFPDoubleValue(const 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();
};
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(Instr* instr) {
char* str = reinterpret_cast<char*>(instr->InstructionBits() & 0x0fffffff);
if (strlen(str) > 0) {
if (coverage_log != NULL) {
fprintf(coverage_log, "%s\n", str);
fflush(coverage_log);
}
instr->SetInstructionBits(0xe1a00000); // Overwrite with nop.
}
sim_->set_pc(sim_->get_pc() + Instr::kInstrSize);
}
#else // ndef GENERATED_CODE_COVERAGE
static void InitializeCoverage() {
}
void Debugger::Stop(Instr* instr) {
const char* str = (const char*)(instr->InstructionBits() & 0x0fffffff);
PrintF("Simulator hit %s\n", str);
sim_->set_pc(sim_->get_pc() + Instr::kInstrSize);
Debug();
}
#endif
int32_t Debugger::GetRegisterValue(int regnum) {
if (regnum == kPCRegister) {
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 != kNoRegister) {
*value = GetRegisterValue(regnum);
return true;
} else {
if (strncmp(desc, "0x", 2) == 0) {
return SScanF(desc + 2, "%x", reinterpret_cast<uint32_t*>(value)) == 1;
} else {
return SScanF(desc, "%u", reinterpret_cast<uint32_t*>(value)) == 1;
}
}
return false;
}
bool Debugger::GetVFPSingleValue(const char* desc, float* value) {
bool is_double;
int regnum = VFPRegisters::Number(desc, &is_double);
if (regnum != kNoRegister && !is_double) {
*value = sim_->get_float_from_s_register(regnum);
return true;
}
return false;
}
bool Debugger::GetVFPDoubleValue(const char* desc, double* value) {
bool is_double;
int regnum = VFPRegisters::Number(desc, &is_double);
if (regnum != kNoRegister && is_double) {
*value = sim_->get_double_from_d_register(regnum);
return true;
}
return false;
}
bool Debugger::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 Debugger::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 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::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];
char* argv[3] = { cmd, arg1, arg2 };
// 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()) {
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 argc = 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)) {
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 (argc == 2) {
int32_t value;
float svalue;
double dvalue;
if (strcmp(arg1, "all") == 0) {
for (int i = 0; i < kNumRegisters; i++) {
value = GetRegisterValue(i);
PrintF("%3s: 0x%08x %10d\n", Registers::Name(i), value, value);
}
} else {
if (GetValue(arg1, &value)) {
PrintF("%s: 0x%08x %d \n", arg1, value, value);
} else if (GetVFPSingleValue(arg1, &svalue)) {
PrintF("%s: %f \n", arg1, svalue);
} else if (GetVFPDoubleValue(arg1, &dvalue)) {
PrintF("%s: %lf \n", arg1, dvalue);
} else {
PrintF("%s unrecognized\n", arg1);
}
}
} else {
PrintF("print <register>\n");
}
} else if ((strcmp(cmd, "po") == 0)
|| (strcmp(cmd, "printobject") == 0)) {
if (argc == 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, "stack") == 0 || strcmp(cmd, "mem") == 0) {
int32_t* cur = NULL;
int32_t* end = NULL;
int next_arg = 1;
if (strcmp(cmd, "stack") == 0) {
cur = reinterpret_cast<int32_t*>(sim_->get_register(Simulator::sp));
} else { // "mem"
int32_t value;
if (!GetValue(arg1, &value)) {
PrintF("%s unrecognized\n", arg1);
continue;
}
cur = reinterpret_cast<int32_t*>(value);
next_arg++;
}
int32_t words;
if (argc == next_arg) {
words = 10;
} else if (argc == next_arg + 1) {
if (!GetValue(argv[next_arg], &words)) {
words = 10;
}
}
end = cur + words;
while (cur < end) {
PrintF(" 0x%08x: 0x%08x %10d\n", cur, *cur, *cur);
cur++;
}
} else if (strcmp(cmd, "disasm") == 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 (argc == 1) {
cur = reinterpret_cast<byte*>(sim_->get_pc());
end = cur + (10 * Instr::kInstrSize);
} else if (argc == 2) {
int32_t value;
if (GetValue(arg1, &value)) {
cur = reinterpret_cast<byte*>(value);
// no length parameter passed, assume 10 instructions
end = cur + (10 * Instr::kInstrSize);
}
} else {
int32_t value1;
int32_t value2;
if (GetValue(arg1, &value1) && GetValue(arg2, &value2)) {
cur = reinterpret_cast<byte*>(value1);
end = cur + (value2 * Instr::kInstrSize);
}
}
while (cur < end) {
dasm.InstructionDecode(buffer, cur);
PrintF(" 0x%08x %s\n", cur, buffer.start());
cur += Instr::kInstrSize;
}
} 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 (argc == 2) {
int32_t value;
if (GetValue(arg1, &value)) {
if (!SetBreakpoint(reinterpret_cast<Instr*>(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("N flag: %d; ", sim_->n_flag_);
PrintF("Z flag: %d; ", sim_->z_flag_);
PrintF("C flag: %d; ", sim_->c_flag_);
PrintF("V flag: %d\n", sim_->v_flag_);
PrintF("INVALID OP flag: %d; ", sim_->inv_op_vfp_flag_);
PrintF("DIV BY ZERO flag: %d; ", sim_->div_zero_vfp_flag_);
PrintF("OVERFLOW flag: %d; ", sim_->overflow_vfp_flag_);
PrintF("UNDERFLOW flag: %d; ", sim_->underflow_vfp_flag_);
PrintF("INEXACT flag: %d; ", sim_->inexact_vfp_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->ConditionField() == special_condition) {
stop_instr->SetInstructionBits(kNopInstr);
} else {
PrintF("Not at debugger stop.");
}
} else if ((strcmp(cmd, "t") == 0) || strcmp(cmd, "trace") == 0) {
::v8::internal::FLAG_trace_sim = !::v8::internal::FLAG_trace_sim;
PrintF("Trace of executed instructions is %s\n",
::v8::internal::FLAG_trace_sim ? "on" : "off");
} 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("stack [<words>]\n");
PrintF(" dump stack content, default dump 10 words)\n");
PrintF("mem <address> [<words>]\n");
PrintF(" dump memory content, default dump 10 words)\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");
PrintF("trace (alias 't')\n");
PrintF(" toogle the tracing of all executed statements\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
}
static bool ICacheMatch(void* one, void* two) {
ASSERT((reinterpret_cast<intptr_t>(one) & CachePage::kPageMask) == 0);
ASSERT((reinterpret_cast<intptr_t>(two) & CachePage::kPageMask) == 0);
return one == two;
}
static uint32_t ICacheHash(void* key) {
return static_cast<uint32_t>(reinterpret_cast<uintptr_t>(key)) >> 2;
}
static bool AllOnOnePage(uintptr_t start, int size) {
intptr_t start_page = (start & ~CachePage::kPageMask);
intptr_t end_page = ((start + size) & ~CachePage::kPageMask);
return start_page == end_page;
}
void Simulator::FlushICache(void* start_addr, size_t size) {
intptr_t start = reinterpret_cast<intptr_t>(start_addr);
int intra_line = (start & CachePage::kLineMask);
start -= intra_line;
size += intra_line;
size = ((size - 1) | CachePage::kLineMask) + 1;
int offset = (start & CachePage::kPageMask);
while (!AllOnOnePage(start, size - 1)) {
int bytes_to_flush = CachePage::kPageSize - offset;
FlushOnePage(start, bytes_to_flush);
start += bytes_to_flush;
size -= bytes_to_flush;
ASSERT_EQ(0, start & CachePage::kPageMask);
offset = 0;
}
if (size != 0) {
FlushOnePage(start, size);
}
}
CachePage* Simulator::GetCachePage(void* page) {
v8::internal::HashMap::Entry* entry = i_cache_->Lookup(page,
ICacheHash(page),
true);
if (entry->value == NULL) {
CachePage* new_page = new CachePage();
entry->value = new_page;
}
return reinterpret_cast<CachePage*>(entry->value);
}
// Flush from start up to and not including start + size.
void Simulator::FlushOnePage(intptr_t start, int size) {
ASSERT(size <= CachePage::kPageSize);
ASSERT(AllOnOnePage(start, size - 1));
ASSERT((start & CachePage::kLineMask) == 0);
ASSERT((size & CachePage::kLineMask) == 0);
void* page = reinterpret_cast<void*>(start & (~CachePage::kPageMask));
int offset = (start & CachePage::kPageMask);
CachePage* cache_page = GetCachePage(page);
char* valid_bytemap = cache_page->ValidityByte(offset);
memset(valid_bytemap, CachePage::LINE_INVALID, size >> CachePage::kLineShift);
}
void Simulator::CheckICache(Instr* instr) {
intptr_t address = reinterpret_cast<intptr_t>(instr);
void* page = reinterpret_cast<void*>(address & (~CachePage::kPageMask));
void* line = reinterpret_cast<void*>(address & (~CachePage::kLineMask));
int offset = (address & CachePage::kPageMask);
CachePage* cache_page = GetCachePage(page);
char* cache_valid_byte = cache_page->ValidityByte(offset);
bool cache_hit = (*cache_valid_byte == CachePage::LINE_VALID);
char* cached_line = cache_page->CachedData(offset & ~CachePage::kLineMask);
if (cache_hit) {
// Check that the data in memory matches the contents of the I-cache.
CHECK(memcmp(reinterpret_cast<void*>(instr),
cache_page->CachedData(offset),
Instr::kInstrSize) == 0);
} else {
// Cache miss. Load memory into the cache.
memcpy(cached_line, line, CachePage::kLineLength);
*cache_valid_byte = CachePage::LINE_VALID;
}
}
// 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);
}
v8::internal::HashMap* Simulator::i_cache_ = NULL;
Simulator::Simulator() {
if (i_cache_ == NULL) {
i_cache_ = new v8::internal::HashMap(&ICacheMatch);
}
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 < num_registers; i++) {
registers_[i] = 0;
}
n_flag_ = false;
z_flag_ = false;
c_flag_ = false;
v_flag_ = false;
// Initializing VFP registers.
// All registers are initialized to zero to start with
// even though s_registers_ & d_registers_ share the same
// physical registers in the target.
for (int i = 0; i < num_s_registers; i++) {
vfp_register[i] = 0;
}
n_flag_FPSCR_ = false;
z_flag_FPSCR_ = false;
c_flag_FPSCR_ = false;
v_flag_FPSCR_ = false;
inv_op_vfp_flag_ = false;
div_zero_vfp_flag_ = false;
overflow_vfp_flag_ = false;
underflow_vfp_flag_ = false;
inexact_vfp_flag_ = false;
// 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 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] = bad_lr;
registers_[lr] = bad_lr;
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_((AL << 28) | (0xf << 24) | call_rt_redirected),
fp_return_(fp_return),
next_(list_) {
Simulator::current()->
FlushICache(reinterpret_cast<void*>(&swi_instruction_),
Instr::kInstrSize);
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(Instr* 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 < num_registers));
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(int reg) const {
ASSERT((reg >= 0) && (reg < num_registers));
return registers_[reg] + ((reg == pc) ? Instr::kPCReadOffset : 0);
}
void Simulator::set_dw_register(int dreg, const int* dbl) {
ASSERT((dreg >= 0) && (dreg < num_d_registers));
registers_[dreg] = dbl[0];
registers_[dreg + 1] = dbl[1];
}
// 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];
}
// Getting from and setting into VFP registers.
void Simulator::set_s_register(int sreg, unsigned int value) {
ASSERT((sreg >= 0) && (sreg < num_s_registers));
vfp_register[sreg] = value;
}
unsigned int Simulator::get_s_register(int sreg) const {
ASSERT((sreg >= 0) && (sreg < num_s_registers));
return vfp_register[sreg];
}
void Simulator::set_s_register_from_float(int sreg, const float flt) {
ASSERT((sreg >= 0) && (sreg < num_s_registers));
// Read the bits from the single precision floating point value
// into the unsigned integer element of vfp_register[] given by index=sreg.
char buffer[sizeof(vfp_register[0])];
memcpy(buffer, &flt, sizeof(vfp_register[0]));
memcpy(&vfp_register[sreg], buffer, sizeof(vfp_register[0]));
}
void Simulator::set_s_register_from_sinteger(int sreg, const int sint) {
ASSERT((sreg >= 0) && (sreg < num_s_registers));
// Read the bits from the integer value into the unsigned integer element of
// vfp_register[] given by index=sreg.
char buffer[sizeof(vfp_register[0])];
memcpy(buffer, &sint, sizeof(vfp_register[0]));
memcpy(&vfp_register[sreg], buffer, sizeof(vfp_register[0]));
}
void Simulator::set_d_register_from_double(int dreg, const double& dbl) {
ASSERT((dreg >= 0) && (dreg < num_d_registers));
// Read the bits from the double precision floating point value into the two
// consecutive unsigned integer elements of vfp_register[] given by index
// 2*sreg and 2*sreg+1.
char buffer[2 * sizeof(vfp_register[0])];
memcpy(buffer, &dbl, 2 * sizeof(vfp_register[0]));
#ifndef BIG_ENDIAN_FLOATING_POINT
memcpy(&vfp_register[dreg * 2], buffer, 2 * sizeof(vfp_register[0]));
#else
memcpy(&vfp_register[dreg * 2], &buffer[4], sizeof(vfp_register[0]));
memcpy(&vfp_register[dreg * 2 + 1], &buffer[0], sizeof(vfp_register[0]));
#endif
}
float Simulator::get_float_from_s_register(int sreg) {
ASSERT((sreg >= 0) && (sreg < num_s_registers));
float sm_val = 0.0;
// Read the bits from the unsigned integer vfp_register[] array
// into the single precision floating point value and return it.
char buffer[sizeof(vfp_register[0])];
memcpy(buffer, &vfp_register[sreg], sizeof(vfp_register[0]));
memcpy(&sm_val, buffer, sizeof(vfp_register[0]));
return(sm_val);
}
int Simulator::get_sinteger_from_s_register(int sreg) {
ASSERT((sreg >= 0) && (sreg < num_s_registers));
int sm_val = 0;
// Read the bits from the unsigned integer vfp_register[] array
// into the single precision floating point value and return it.
char buffer[sizeof(vfp_register[0])];
memcpy(buffer, &vfp_register[sreg], sizeof(vfp_register[0]));
memcpy(&sm_val, buffer, sizeof(vfp_register[0]));
return(sm_val);
}
double Simulator::get_double_from_d_register(int dreg) {
ASSERT((dreg >= 0) && (dreg < num_d_registers));
double dm_val = 0.0;
// Read the bits from the unsigned integer vfp_register[] array
// into the double precision floating point value and return it.
char buffer[2 * sizeof(vfp_register[0])];
#ifdef BIG_ENDIAN_FLOATING_POINT
memcpy(&buffer[0], &vfp_register[2 * dreg + 1], sizeof(vfp_register[0]));
memcpy(&buffer[4], &vfp_register[2 * dreg], sizeof(vfp_register[0]));
#else
memcpy(buffer, &vfp_register[2 * dreg], 2 * sizeof(vfp_register[0]));
#endif
memcpy(&dm_val, buffer, 2 * sizeof(vfp_register[0]));
return(dm_val);
}
// For use in calls that take two double values, constructed from r0, r1, r2
// and r3.
void Simulator::GetFpArgs(double* x, double* y) {
// We use a char buffer to get around the strict-aliasing rules which
// otherwise allow the compiler to optimize away the copy.
char buffer[2 * sizeof(registers_[0])];
// Registers 0 and 1 -> x.
memcpy(buffer, registers_, sizeof(buffer));
memcpy(x, buffer, sizeof(buffer));
// Registers 2 and 3 -> y.
memcpy(buffer, registers_ + 2, sizeof(buffer));
memcpy(y, buffer, sizeof(buffer));
}
void Simulator::SetFpResult(const double& result) {
char buffer[2 * sizeof(registers_[0])];
memcpy(buffer, &result, sizeof(buffer));
// result -> registers 0 and 1.
memcpy(registers_, buffer, sizeof(buffer));
}
void Simulator::TrashCallerSaveRegisters() {
// We don't trash the registers with the return value.
registers_[2] = 0x50Bad4U;
registers_[3] = 0x50Bad4U;
registers_[12] = 0x50Bad4U;
}
// Some Operating Systems allow unaligned access on ARMv7 targets. We
// assume that unaligned accesses are not allowed unless the v8 build system
// defines the CAN_USE_UNALIGNED_ACCESSES macro to be non-zero.
// The following statements below describes the behavior of the ARM CPUs
// that don't support unaligned access.
// Some ARM platforms raise an interrupt on detecting unaligned access.
// On others it does a funky rotation thing. For now we
// simply disallow unaligned reads. 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 ARM-like behaviour on unaligned accesses for those ARM
// targets that don't support unaligned loads and stores.
int Simulator::ReadW(int32_t addr, Instr* instr) {
#if V8_TARGET_CAN_READ_UNALIGNED
intptr_t* ptr = reinterpret_cast<intptr_t*>(addr);
return *ptr;
#else
if ((addr & 3) == 0) {
intptr_t* ptr = reinterpret_cast<intptr_t*>(addr);
return *ptr;
}
PrintF("Unaligned read at 0x%08x, pc=%p\n", addr, instr);
UNIMPLEMENTED();
return 0;
#endif
}
void Simulator::WriteW(int32_t addr, int value, Instr* instr) {
#if V8_TARGET_CAN_READ_UNALIGNED
intptr_t* ptr = reinterpret_cast<intptr_t*>(addr);
*ptr = value;
return;
#else
if ((addr & 3) == 0) {
intptr_t* ptr = reinterpret_cast<intptr_t*>(addr);
*ptr = value;
return;
}
PrintF("Unaligned write at 0x%08x, pc=%p\n", addr, instr);
UNIMPLEMENTED();
#endif
}
uint16_t Simulator::ReadHU(int32_t addr, Instr* instr) {
#if V8_TARGET_CAN_READ_UNALIGNED
uint16_t* ptr = reinterpret_cast<uint16_t*>(addr);
return *ptr;
#else
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);
UNIMPLEMENTED();
return 0;
#endif
}
int16_t Simulator::ReadH(int32_t addr, Instr* instr) {
#if V8_TARGET_CAN_READ_UNALIGNED
int16_t* ptr = reinterpret_cast<int16_t*>(addr);
return *ptr;
#else
if ((addr & 1) == 0) {
int16_t* ptr = reinterpret_cast<int16_t*>(addr);
return *ptr;
}
PrintF("Unaligned signed halfword read at 0x%08x\n", addr);
UNIMPLEMENTED();
return 0;
#endif
}
void Simulator::WriteH(int32_t addr, uint16_t value, Instr* instr) {
#if V8_TARGET_CAN_READ_UNALIGNED
uint16_t* ptr = reinterpret_cast<uint16_t*>(addr);
*ptr = value;
return;
#else
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);
UNIMPLEMENTED();
#endif
}
void Simulator::WriteH(int32_t addr, int16_t value, Instr* instr) {
#if V8_TARGET_CAN_READ_UNALIGNED
int16_t* ptr = reinterpret_cast<int16_t*>(addr);
*ptr = value;
return;
#else
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);
UNIMPLEMENTED();
#endif
}
uint8_t Simulator::ReadBU(int32_t addr) {
uint8_t* ptr = reinterpret_cast<uint8_t*>(addr);
return *ptr;
}
int8_t Simulator::ReadB(int32_t addr) {
int8_t* ptr = reinterpret_cast<int8_t*>(addr);
return *ptr;
}
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;
}
int32_t* Simulator::ReadDW(int32_t addr) {
#if V8_TARGET_CAN_READ_UNALIGNED
int32_t* ptr = reinterpret_cast<int32_t*>(addr);
return ptr;
#else
if ((addr & 3) == 0) {
int32_t* ptr = reinterpret_cast<int32_t*>(addr);
return ptr;
}
PrintF("Unaligned read at 0x%08x\n", addr);
UNIMPLEMENTED();
return 0;
#endif
}
void Simulator::WriteDW(int32_t addr, int32_t value1, int32_t value2) {
#if V8_TARGET_CAN_READ_UNALIGNED
int32_t* ptr = reinterpret_cast<int32_t*>(addr);
*ptr++ = value1;
*ptr = value2;
return;
#else
if ((addr & 3) == 0) {
int32_t* ptr = reinterpret_cast<int32_t*>(addr);
*ptr++ = value1;
*ptr = value2;
return;
}
PrintF("Unaligned write at 0x%08x\n", addr);
UNIMPLEMENTED();
#endif
}
// 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(Instr* instr, const char* format) {
PrintF("Simulator found unsupported instruction:\n 0x%08x: %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;
}
// Support for VFP comparisons.
void Simulator::Compute_FPSCR_Flags(double val1, double val2) {
if (isnan(val1) || isnan(val2)) {
n_flag_FPSCR_ = false;
z_flag_FPSCR_ = false;
c_flag_FPSCR_ = true;
v_flag_FPSCR_ = true;
// All non-NaN cases.
} else if (val1 == val2) {
n_flag_FPSCR_ = false;
z_flag_FPSCR_ = true;
c_flag_FPSCR_ = true;
v_flag_FPSCR_ = false;
} else if (val1 < val2) {
n_flag_FPSCR_ = true;
z_flag_FPSCR_ = false;
c_flag_FPSCR_ = false;
v_flag_FPSCR_ = false;
} else {
// Case when (val1 > val2).
n_flag_FPSCR_ = false;
z_flag_FPSCR_ = false;
c_flag_FPSCR_ = true;
v_flag_FPSCR_ = false;
}
}
void Simulator::Copy_FPSCR_to_APSR() {
n_flag_ = n_flag_FPSCR_;
z_flag_ = z_flag_FPSCR_;
c_flag_ = c_flag_FPSCR_;
v_flag_ = v_flag_FPSCR_;
}
// 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
int 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) {
int rn = instr->RnField();
int32_t rn_val = get_register(rn);
int rlist = instr->RlistField();
int num_regs = count_bits(rlist);
intptr_t start_address = 0;
intptr_t end_address = 0;
switch (instr->PUField()) {
case 0: {
// Print("da");
UNIMPLEMENTED();
break;
}
case 1: {
// Print("ia");
start_address = rn_val;
end_address = rn_val + (num_regs * 4) - 4;
rn_val = rn_val + (num_regs * 4);
break;
}
case 2: {
// Print("db");
start_address = rn_val - (num_regs * 4);
end_address = rn_val - 4;
rn_val = start_address;
break;
}
case 3: {
// Print("ib");
UNIMPLEMENTED();
break;
}
default: {
UNREACHABLE();
break;
}
}
if (instr->HasW()) {
set_register(rn, rn_val);
}
intptr_t* address = reinterpret_cast<intptr_t*>(start_address);
int reg = 0;
while (rlist != 0) {
if ((rlist & 1) != 0) {
if (load) {
set_register(reg, *address);
} else {
*address = get_register(reg);
}
address += 1;
}
reg++;
rlist >>= 1;
}
ASSERT(end_address == ((intptr_t)address) - 4);
}
// 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)(int32_t arg0,
int32_t arg1,
int32_t arg2,
int32_t arg3);
// Software interrupt instructions are used by the simulator to call into the
// C-based V8 runtime.
void Simulator::SoftwareInterrupt(Instr* instr) {
int swi = instr->SwiField();
switch (swi) {
case call_rt_redirected: {
// Check if stack is aligned. Error if not aligned is reported below to
// include information on the function called.
bool stack_aligned =
(get_register(sp)
& (::v8::internal::FLAG_sim_stack_alignment - 1)) == 0;
Redirection* redirection = Redirection::FromSwiInstruction(instr);
int32_t arg0 = get_register(r0);
int32_t arg1 = get_register(r1);
int32_t arg2 = get_register(r2);
int32_t arg3 = get_register(r3);
// 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_lr = get_register(lr);
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 || !stack_aligned) {
double x, y;
GetFpArgs(&x, &y);
PrintF("Call to host function at %p with args %f, %f",
FUNCTION_ADDR(target), x, y);
if (!stack_aligned) {
PrintF(" with unaligned stack %08x\n", get_register(sp));
}
PrintF("\n");
}
CHECK(stack_aligned);
double result = target(arg0, arg1, arg2, arg3);
SetFpResult(result);
} else {
intptr_t external =
reinterpret_cast<int32_t>(redirection->external_function());
SimulatorRuntimeCall target =
reinterpret_cast<SimulatorRuntimeCall>(external);
if (::v8::internal::FLAG_trace_sim || !stack_aligned) {
PrintF(
"Call to host function at %p with args %08x, %08x, %08x, %08x",
FUNCTION_ADDR(target),
arg0,
arg1,
arg2,
arg3);
if (!stack_aligned) {
PrintF(" with unaligned stack %08x\n", get_register(sp));
}
PrintF("\n");
}
CHECK(stack_aligned);
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(r0, lo_res);
set_register(r1, hi_res);
}
set_register(lr, saved_lr);
set_pc(get_register(lr));
break;
}
case break_point: {
Debugger dbg(this);
dbg.Debug();
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) {
int type = instr->TypeField();
if ((type == 0) && instr->IsSpecialType0()) {
// multiply instruction or extra loads and stores
if (instr->Bits(7, 4) == 9) {
if (instr->Bit(24) == 0) {
// Raw field decoding here. Multiply instructions have their Rd in
// funny places.
int rn = instr->RnField();
int rm = instr->RmField();
int rs = instr->RsField();
int32_t rs_val = get_register(rs);
int32_t rm_val = get_register(rm);
if (instr->Bit(23) == 0) {
if (instr->Bit(21) == 0) {
// The MUL instruction description (A 4.1.33) refers to Rd as being
// the destination for the operation, but it confusingly uses the
// Rn field to encode it.
// Format(instr, "mul'cond's 'rn, 'rm, 'rs");
int rd = rn; // Remap the rn field to the Rd register.
int32_t alu_out = rm_val * rs_val;
set_register(rd, alu_out);
if (instr->HasS()) {
SetNZFlags(alu_out);
}
} else {
// The MLA instruction description (A 4.1.28) refers to the order
// of registers as "Rd, Rm, Rs, Rn". But confusingly it uses the
// Rn field to encode the Rd register and the Rd field to encode
// the Rn register.
Format(instr, "mla'cond's 'rn, 'rm, 'rs, 'rd");
}
} else {
// The signed/long multiply instructions use the terms RdHi and RdLo
// when referring to the target registers. They are mapped to the Rn
// and Rd fields as follows:
// RdLo == Rd
// RdHi == Rn (This is confusingly stored in variable rd here
// because the mul instruction from above uses the
// Rn field to encode the Rd register. Good luck figuring
// this out without reading the ARM instruction manual
// at a very detailed level.)
// Format(instr, "'um'al'cond's 'rd, 'rn, 'rs, 'rm");
int rd_hi = rn; // Remap the rn field to the RdHi register.
int rd_lo = instr->RdField();
int32_t hi_res = 0;
int32_t lo_res = 0;
if (instr->Bit(22) == 1) {
int64_t left_op = static_cast<int32_t>(rm_val);
int64_t right_op = static_cast<int32_t>(rs_val);
uint64_t result = left_op * right_op;
hi_res = static_cast<int32_t>(result >> 32);
lo_res = static_cast<int32_t>(result & 0xffffffff);
} else {
// unsigned multiply
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;
hi_res = static_cast<int32_t>(result >> 32);
lo_res = static_cast<int32_t>(result & 0xffffffff);
}
set_register(rd_lo, lo_res);
set_register(rd_hi, hi_res);
if (instr->HasS()) {
UNIMPLEMENTED();
}
}
} else {
UNIMPLEMENTED(); // Not used by V8.
}
} else {
// extra load/store instructions
int rd = instr->RdField();
int rn = instr->RnField();
int32_t rn_val = get_register(rn);
int32_t addr = 0;
if (instr->Bit(22) == 0) {
int rm = instr->RmField();
int32_t rm_val = get_register(rm);
switch (instr->PUField()) {
case 0: {
// Format(instr, "'memop'cond'sign'h 'rd, ['rn], -'rm");
ASSERT(!instr->HasW());
addr = rn_val;
rn_val -= rm_val;
set_register(rn, rn_val);
break;
}
case 1: {
// Format(instr, "'memop'cond'sign'h 'rd, ['rn], +'rm");
ASSERT(!instr->HasW());
addr = rn_val;
rn_val += rm_val;
set_register(rn, rn_val);
break;
}
case 2: {
// Format(instr, "'memop'cond'sign'h 'rd, ['rn, -'rm]'w");
rn_val -= rm_val;
addr = rn_val;
if (instr->HasW()) {
set_register(rn, rn_val);
}
break;
}
case 3: {
// Format(instr, "'memop'cond'sign'h 'rd, ['rn, +'rm]'w");
rn_val += rm_val;
addr = rn_val;
if (instr->HasW()) {
set_register(rn, rn_val);
}
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'sign'h 'rd, ['rn], #-'off8");
ASSERT(!instr->HasW());
addr = rn_val;
rn_val -= imm_val;
set_register(rn, rn_val);
break;
}
case 1: {
// Format(instr, "'memop'cond'sign'h 'rd, ['rn], #+'off8");
ASSERT(!instr->HasW());
addr = rn_val;
rn_val += imm_val;
set_register(rn, rn_val);
break;
}
case 2: {
// Format(instr, "'memop'cond'sign'h 'rd, ['rn, #-'off8]'w");
rn_val -= imm_val;
addr = rn_val;
if (instr->HasW()) {
set_register(rn, rn_val);
}
break;
}
case 3: {
// Format(instr, "'memop'cond'sign'h 'rd, ['rn, #+'off8]'w");
rn_val += imm_val;
addr = rn_val;
if (instr->HasW()) {
set_register(rn, rn_val);
}
break;
}
default: {
// The PU field is a 2-bit field.
UNREACHABLE();
break;
}
}
}
if (((instr->Bits(7, 4) & 0xd) == 0xd) && (instr->Bit(20) == 0)) {
ASSERT((rd % 2) == 0);
if (instr->HasH()) {
// The strd instruction.
int32_t value1 = get_register(rd);
int32_t value2 = get_register(rd+1);
WriteDW(addr, value1, value2);
} else {
// The ldrd instruction.
int* rn_data = ReadDW(addr);
set_dw_register(rd, rn_data);
}
} else if (instr->HasH()) {
if (instr->HasSign()) {
if (instr->HasL()) {
int16_t val = ReadH(addr, instr);
set_register(rd, val);
} else {
int16_t val = get_register(rd);
WriteH(addr, val, instr);
}
} else {
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 {
// signed byte loads
ASSERT(instr->HasSign());
ASSERT(instr->HasL());
int8_t val = ReadB(addr);
set_register(rd, val);
}
return;
}
} else if ((type == 0) && instr->IsMiscType0()) {
if (instr->Bits(22, 21) == 1) {
int rm = instr->RmField();
switch (instr->Bits(7, 4)) {
case BX:
set_pc(get_register(rm));
break;
case BLX: {
uint32_t old_pc = get_pc();
set_pc(get_register(rm));
set_register(lr, old_pc + Instr::kInstrSize);
break;
}
case BKPT:
v8::internal::OS::DebugBreak();
break;
default:
UNIMPLEMENTED();
}
} else if (instr->Bits(22, 21) == 3) {
int rm = instr->RmField();
int rd = instr->RdField();
switch (instr->Bits(7, 4)) {
case CLZ: {
uint32_t bits = get_register(rm);
int leading_zeros = 0;
if (bits == 0) {
leading_zeros = 32;
} else {
while ((bits & 0x80000000u) == 0) {
bits <<= 1;
leading_zeros++;
}
}
set_register(rd, leading_zeros);
break;
}
default:
UNIMPLEMENTED();
}
} else {
PrintF("%08x\n", instr->InstructionBits());
UNIMPLEMENTED();
}
} else {
int rd = instr->RdField();
int rn = instr->RnField();
int32_t rn_val = get_register(rn);
int32_t shifter_operand = 0;
bool shifter_carry_out = 0;
if (type == 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");
break;
}
case SBC: {
Format(instr, "sbc'cond's 'rd, 'rn, 'shift_rm");
Format(instr, "sbc'cond's 'rd, 'rn, 'imm");
break;
}
case RSC: {
Format(instr, "rsc'cond's 'rd, 'rn, 'shift_rm");
Format(instr, "rsc'cond's 'rd, 'rn, 'imm");
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 {
// Format(instr, "movw'cond 'rd, 'imm").
alu_out = instr->ImmedMovwMovtField();
set_register(rd, alu_out);
}
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 {
// Other instructions matching this pattern are handled in the
// miscellaneous instructions part above.
UNREACHABLE();
}
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 {
// Format(instr, "movt'cond 'rd, 'imm").
alu_out = (get_register(rd) & 0xffff) |
(instr->ImmedMovwMovtField() << 16);
set_register(rd, alu_out);
}
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 {
// Other instructions matching this pattern are handled in the
// miscellaneous instructions part above.
UNREACHABLE();
}
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) {
int rd = instr->RdField();
int rn = instr->RnField();
int32_t rn_val = get_register(rn);
int32_t im_val = instr->Offset12Field();
int32_t addr = 0;
switch (instr->PUField()) {
case 0: {
// Format(instr, "'memop'cond'b 'rd, ['rn], #-'off12");
ASSERT(!instr->HasW());
addr = rn_val;
rn_val -= im_val;
set_register(rn, rn_val);
break;
}
case 1: {
// Format(instr, "'memop'cond'b 'rd, ['rn], #+'off12");
ASSERT(!instr->HasW());
addr = rn_val;
rn_val += im_val;
set_register(rn, rn_val);
break;
}
case 2: {
// Format(instr, "'memop'cond'b 'rd, ['rn, #-'off12]'w");
rn_val -= im_val;
addr = rn_val;
if (instr->HasW()) {
set_register(rn, rn_val);
}
break;
}
case 3: {
// Format(instr, "'memop'cond'b 'rd, ['rn, #+'off12]'w");
rn_val += im_val;
addr = rn_val;
if (instr->HasW()) {
set_register(rn, rn_val);
}
break;
}
default: {
UNREACHABLE();
break;
}
}
if (instr->HasB()) {
if (instr->HasL()) {
byte val = ReadBU(addr);
set_register(rd, val);
} else {
byte 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) {
int rd = instr->RdField();
int rn = instr->RnField();
int32_t rn_val = get_register(rn);
bool shifter_carry_out = 0;
int32_t shifter_operand = GetShiftRm(instr, &shifter_carry_out);
int32_t addr = 0;
switch (instr->PUField()) {
case 0: {
ASSERT(!instr->HasW());
Format(instr, "'memop'cond'b 'rd, ['rn], -'shift_rm");
break;
}
case 1: {
ASSERT(!instr->HasW());
Format(instr, "'memop'cond'b 'rd, ['rn], +'shift_rm");
break;
}
case 2: {
// Format(instr, "'memop'cond'b 'rd, ['rn, -'shift_rm]'w");
addr = rn_val - shifter_operand;
if (instr->HasW()) {
set_register(rn, addr);
}
break;
}
case 3: {
if (instr->HasW() && (instr->Bits(6, 4) == 0x5)) {
uint32_t widthminus1 = static_cast<uint32_t>(instr->Bits(20, 16));
uint32_t lsbit = static_cast<uint32_t>(instr->Bits(11, 7));
uint32_t msbit = widthminus1 + lsbit;
if (msbit <= 31) {
if (instr->Bit(22)) {
// ubfx - unsigned bitfield extract.
uint32_t rm_val =
static_cast<uint32_t>(get_register(instr->RmField()));
uint32_t extr_val = rm_val << (31 - msbit);
extr_val = extr_val >> (31 - widthminus1);
set_register(instr->RdField(), extr_val);
} else {
// sbfx - signed bitfield extract.
int32_t rm_val = get_register(instr->RmField());
int32_t extr_val = rm_val << (31 - msbit);
extr_val = extr_val >> (31 - widthminus1);
set_register(instr->RdField(), extr_val);
}
} else {
UNREACHABLE();
}
return;
} else if (!instr->HasW() && (instr->Bits(6, 4) == 0x1)) {
uint32_t lsbit = static_cast<uint32_t>(instr->Bits(11, 7));
uint32_t msbit = static_cast<uint32_t>(instr->Bits(20, 16));
if (msbit >= lsbit) {
// bfc or bfi - bitfield clear/insert.
uint32_t rd_val =
static_cast<uint32_t>(get_register(instr->RdField()));
uint32_t bitcount = msbit - lsbit + 1;
uint32_t mask = (1 << bitcount) - 1;
rd_val &= ~(mask << lsbit);
if (instr->RmField() != 15) {
// bfi - bitfield insert.
uint32_t rm_val =
static_cast<uint32_t>(get_register(instr->RmField()));
rm_val &= mask;
rd_val |= rm_val << lsbit;
}
set_register(instr->RdField(), rd_val);
} else {
UNREACHABLE();
}
return;
} else {
// Format(instr, "'memop'cond'b 'rd, ['rn, +'shift_rm]'w");
addr = rn_val + shifter_operand;
if (instr->HasW()) {
set_register(rn, addr);
}
}
break;
}
default: {
UNREACHABLE();
break;
}
}
if (instr->HasB()) {
if (instr->HasL()) {
uint8_t byte = ReadB(addr);
set_register(rd, byte);
} else {
uint8_t byte = get_register(rd);
WriteB(addr, byte);
}
} 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);
intptr_t pc_address = get_pc();
if (instr->HasLink()) {
set_register(lr, pc_address + Instr::kInstrSize);
}
int pc_reg = get_register(pc);
set_pc(pc_reg + off);
}
void Simulator::DecodeType6(Instr* instr) {
DecodeType6CoprocessorIns(instr);
}
void Simulator::DecodeType7(Instr* instr) {
if (instr->Bit(24) == 1) {
SoftwareInterrupt(instr);
} else {
DecodeTypeVFP(instr);
}
}
void Simulator::DecodeUnconditional(Instr* instr) {
if (instr->Bits(7, 4) == 0x0B && instr->Bits(27, 25) == 0 && instr->HasL()) {
// Load halfword instruction, either register or immediate offset.
int rd = instr->RdField();
int rn = instr->RnField();
int32_t rn_val = get_register(rn);
int32_t addr = 0;
int32_t offset;
if (instr->Bit(22) == 0) {
// Register offset.
int rm = instr->RmField();
offset = get_register(rm);
} else {
// Immediate offset
offset = instr->Bits(3, 0) + (instr->Bits(11, 8) << 4);
}
switch (instr->PUField()) {
case 0: {
// Post index, negative.
ASSERT(!instr->HasW());
addr = rn_val;
rn_val -= offset;
set_register(rn, rn_val);
break;
}
case 1: {
// Post index, positive.
ASSERT(!instr->HasW());
addr = rn_val;
rn_val += offset;
set_register(rn, rn_val);
break;
}
case 2: {
// Pre index or offset, negative.
rn_val -= offset;
addr = rn_val;
if (instr->HasW()) {
set_register(rn, rn_val);
}
break;
}
case 3: {
// Pre index or offset, positive.
rn_val += offset;
addr = rn_val;
if (instr->HasW()) {
set_register(rn, rn_val);
}
break;
}
default: {
// The PU field is a 2-bit field.
UNREACHABLE();
break;
}
}
// Not sign extending, so load as unsigned.
uint16_t halfword = ReadH(addr, instr);
set_register(rd, halfword);
} else {
Debugger dbg(this);
dbg.Stop(instr);
}
}
// Depending on value of last_bit flag glue register code from vm and m values
// (where m is expected to be a single bit).
static int GlueRegCode(bool last_bit, int vm, int m) {
return last_bit ? ((vm << 1) | m) : ((m << 4) | vm);
}
// void Simulator::DecodeTypeVFP(Instr* instr)
// The Following ARMv7 VFPv instructions are currently supported.
// vmov :Sn = Rt
// vmov :Rt = Sn
// vcvt: Dd = Sm
// vcvt: Sd = Dm
// Dd = vadd(Dn, Dm)
// Dd = vsub(Dn, Dm)
// Dd = vmul(Dn, Dm)
// Dd = vdiv(Dn, Dm)
// vcmp(Dd, Dm)
// vmrs
// Dd = vsqrt(Dm)
void Simulator::DecodeTypeVFP(Instr* instr) {
ASSERT((instr->TypeField() == 7) && (instr->Bit(24) == 0x0) );
ASSERT(instr->Bits(11, 9) == 0x5);
int vm = instr->VmField();
int vd = instr->VdField();
int vn = instr->VnField();
if (instr->Bit(4) == 0) {
if (instr->Opc1Field() == 0x7) {
// Other data processing instructions
if ((instr->Opc2Field() == 0x0) && (instr->Opc3Field() == 0x1)) {
// vmov register to register.
if (instr->SzField() == 0x1) {
set_d_register_from_double(vd, get_double_from_d_register(vm));
} else {
UNREACHABLE(); // Not used by V8.
}
} else if ((instr->Opc2Field() == 0x7) && (instr->Opc3Field() == 0x3)) {
DecodeVCVTBetweenDoubleAndSingle(instr);
} else if ((instr->Opc2Field() == 0x8) && (instr->Opc3Field() & 0x1)) {
DecodeVCVTBetweenFloatingPointAndInteger(instr);
} else if (((instr->Opc2Field() >> 1) == 0x6) &&
(instr->Opc3Field() & 0x1)) {
DecodeVCVTBetweenFloatingPointAndInteger(instr);
} else if (((instr->Opc2Field() == 0x4) || (instr->Opc2Field() == 0x5)) &&
(instr->Opc3Field() & 0x1)) {
DecodeVCMP(instr);
} else if (((instr->Opc2Field() == 0x1)) && (instr->Opc3Field() == 0x3)) {
// vsqrt
double dm_value = get_double_from_d_register(vm);
double dd_value = sqrt(dm_value);
set_d_register_from_double(vd, dd_value);
} else {
UNREACHABLE(); // Not used by V8.
}
} else if (instr->Opc1Field() == 0x3) {
if (instr->SzField() != 0x1) {
UNREACHABLE(); // Not used by V8.
}
if (instr->Opc3Field() & 0x1) {
// vsub
double dn_value = get_double_from_d_register(vn);
double dm_value = get_double_from_d_register(vm);
double dd_value = dn_value - dm_value;
set_d_register_from_double(vd, dd_value);
} else {
// vadd
double dn_value = get_double_from_d_register(vn);
double dm_value = get_double_from_d_register(vm);
double dd_value = dn_value + dm_value;
set_d_register_from_double(vd, dd_value);
}
} else if ((instr->Opc1Field() == 0x2) && !(instr->Opc3Field() & 0x1)) {
// vmul
if (instr->SzField() != 0x1) {
UNREACHABLE(); // Not used by V8.
}
double dn_value = get_double_from_d_register(vn);
double dm_value = get_double_from_d_register(vm);
double dd_value = dn_value * dm_value;
set_d_register_from_double(vd, dd_value);
} else if ((instr->Opc1Field() == 0x4) && !(instr->Opc3Field() & 0x1)) {
// vdiv
if (instr->SzField() != 0x1) {
UNREACHABLE(); // Not used by V8.
}
double dn_value = get_double_from_d_register(vn);
double dm_value = get_double_from_d_register(vm);
double dd_value = dn_value / dm_value;
set_d_register_from_double(vd, dd_value);
} else {
UNIMPLEMENTED(); // Not used by V8.
}
} else {
if ((instr->VCField() == 0x0) &&
(instr->VAField() == 0x0)) {
DecodeVMOVBetweenCoreAndSinglePrecisionRegisters(instr);
} else if ((instr->VLField() == 0x1) &&
(instr->VCField() == 0x0) &&
(instr->VAField() == 0x7) &&
(instr->Bits(19, 16) == 0x1)) {
// vmrs
if (instr->RtField() == 0xF)
Copy_FPSCR_to_APSR();
else
UNIMPLEMENTED(); // Not used by V8.
} else {
UNIMPLEMENTED(); // Not used by V8.
}
}
}
void Simulator::DecodeVMOVBetweenCoreAndSinglePrecisionRegisters(Instr* instr) {
ASSERT((instr->Bit(4) == 1) && (instr->VCField() == 0x0) &&
(instr->VAField() == 0x0));
int t = instr->RtField();
int n = GlueRegCode(true, instr->VnField(), instr->NField());
bool to_arm_register = (instr->VLField() == 0x1);
if (to_arm_register) {
int32_t int_value = get_sinteger_from_s_register(n);
set_register(t, int_value);
} else {
int32_t rs_val = get_register(t);
set_s_register_from_sinteger(n, rs_val);
}
}
void Simulator::DecodeVCMP(Instr* instr) {
ASSERT((instr->Bit(4) == 0) && (instr->Opc1Field() == 0x7));
ASSERT(((instr->Opc2Field() == 0x4) || (instr->Opc2Field() == 0x5)) &&
(instr->Opc3Field() & 0x1));
// Comparison.
bool dp_operation = (instr->SzField() == 1);
if (instr->Bit(7) != 0) {
// Raising exceptions for quiet NaNs are not supported.
UNIMPLEMENTED(); // Not used by V8.
}
int d = GlueRegCode(!dp_operation, instr->VdField(), instr->DField());
int m = GlueRegCode(!dp_operation, instr->VmField(), instr->MField());
if (dp_operation) {
double dd_value = get_double_from_d_register(d);
double dm_value = get_double_from_d_register(m);
Compute_FPSCR_Flags(dd_value, dm_value);
} else {
UNIMPLEMENTED(); // Not used by V8.
}
}
void Simulator::DecodeVCVTBetweenDoubleAndSingle(Instr* instr) {
ASSERT((instr->Bit(4) == 0) && (instr->Opc1Field() == 0x7));
ASSERT((instr->Opc2Field() == 0x7) && (instr->Opc3Field() == 0x3));
bool double_to_single = (instr->SzField() == 1);
int dst = GlueRegCode(double_to_single, instr->VdField(), instr->DField());
int src = GlueRegCode(!double_to_single, instr->VmField(), instr->MField());
if (double_to_single) {
double val = get_double_from_d_register(src);
set_s_register_from_float(dst, static_cast<float>(val));
} else {
float val = get_float_from_s_register(src);
set_d_register_from_double(dst, static_cast<double>(val));
}
}
void Simulator::DecodeVCVTBetweenFloatingPointAndInteger(Instr* instr) {
ASSERT((instr->Bit(4) == 0) && (instr->Opc1Field() == 0x7));
ASSERT(((instr->Opc2Field() == 0x8) && (instr->Opc3Field() & 0x1)) ||
(((instr->Opc2Field() >> 1) == 0x6) && (instr->Opc3Field() & 0x1)));
// Conversion between floating-point and integer.
int vd = instr->VdField();
int d = instr->DField();
int vm = instr->VmField();
int m = instr->MField();
bool to_integer = (instr->Bit(18) == 1);
bool dp_operation = (instr->SzField() == 1);
if (to_integer) {
bool unsigned_integer = (instr->Bit(16) == 0);
if (instr->Bit(7) != 1) {
// Only rounding towards zero supported.
UNIMPLEMENTED(); // Not used by V8.
}
int dst = GlueRegCode(true, vd, d);
int src = GlueRegCode(!dp_operation, vm, m);
if (dp_operation) {
double val = get_double_from_d_register(src);
int sint = unsigned_integer ? static_cast<uint32_t>(val) :
static_cast<int32_t>(val);
set_s_register_from_sinteger(dst, sint);
} else {
float val = get_float_from_s_register(src);
int sint = unsigned_integer ? static_cast<uint32_t>(val) :
static_cast<int32_t>(val);
set_s_register_from_sinteger(dst, sint);
}
} else {
bool unsigned_integer = (instr->Bit(7) == 0);
int dst = GlueRegCode(!dp_operation, vd, d);
int src = GlueRegCode(true, vm, m);
int val = get_sinteger_from_s_register(src);
if (dp_operation) {
if (unsigned_integer) {
set_d_register_from_double(dst,
static_cast<double>((uint32_t)val));
} else {
set_d_register_from_double(dst, static_cast<double>(val));
}
} else {
if (unsigned_integer) {
set_s_register_from_float(dst,
static_cast<float>((uint32_t)val));
} else {
set_s_register_from_float(dst, static_cast<float>(val));
}
}
}
}
// void Simulator::DecodeType6CoprocessorIns(Instr* instr)
// Decode Type 6 coprocessor instructions.
// Dm = vmov(Rt, Rt2)
// <Rt, Rt2> = vmov(Dm)
// Ddst = MEM(Rbase + 4*offset).
// MEM(Rbase + 4*offset) = Dsrc.
void Simulator::DecodeType6CoprocessorIns(Instr* instr) {
ASSERT((instr->TypeField() == 6));
if (instr->CoprocessorField() == 0xA) {
switch (instr->OpcodeField()) {
case 0x8:
case 0xC: { // Load and store float to memory.
int rn = instr->RnField();
int vd = instr->VdField();
int offset = instr->Immed8Field();
if (!instr->HasU()) {
offset = -offset;
}
int32_t address = get_register(rn) + 4 * offset;
if (instr->HasL()) {
// Load double from memory: vldr.
set_s_register_from_sinteger(vd, ReadW(address, instr));
} else {
// Store double to memory: vstr.
WriteW(address, get_sinteger_from_s_register(vd), instr);
}
break;
}
default:
UNIMPLEMENTED(); // Not used by V8.
break;
}
} else if (instr->CoprocessorField() == 0xB) {
switch (instr->OpcodeField()) {
case 0x2:
// Load and store double to two GP registers
if (instr->Bits(7, 4) != 0x1) {
UNIMPLEMENTED(); // Not used by V8.
} else {
int rt = instr->RtField();
int rn = instr->RnField();
int vm = instr->VmField();
if (instr->HasL()) {
int32_t rt_int_value = get_sinteger_from_s_register(2*vm);
int32_t rn_int_value = get_sinteger_from_s_register(2*vm+1);
set_register(rt, rt_int_value);
set_register(rn, rn_int_value);
} else {
int32_t rs_val = get_register(rt);
int32_t rn_val = get_register(rn);
set_s_register_from_sinteger(2*vm, rs_val);
set_s_register_from_sinteger((2*vm+1), rn_val);
}
}
break;
case 0x8:
case 0xC: { // Load and store double to memory.
int rn = instr->RnField();
int vd = instr->VdField();
int offset = instr->Immed8Field();
if (!instr->HasU()) {
offset = -offset;
}
int32_t address = get_register(rn) + 4 * offset;
if (instr->HasL()) {
// Load double from memory: vldr.
set_s_register_from_sinteger(2*vd, ReadW(address, instr));
set_s_register_from_sinteger(2*vd + 1, ReadW(address + 4, instr));
} else {
// Store double to memory: vstr.
WriteW(address, get_sinteger_from_s_register(2*vd), instr);
WriteW(address + 4, get_sinteger_from_s_register(2*vd + 1), instr);
}
break;
}
default:
UNIMPLEMENTED(); // Not used by V8.
break;
}
} else {
UNIMPLEMENTED(); // Not used by V8.
}
}
// Executes the current instruction.
void Simulator::InstructionDecode(Instr* instr) {
if (v8::internal::FLAG_check_icache) {
CheckICache(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());
}
if (instr->ConditionField() == special_condition) {
DecodeUnconditional(instr);
} 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() {
// 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) {
Instr* instr = reinterpret_cast<Instr*>(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) {
Instr* instr = reinterpret_cast<Instr*>(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(r0, va_arg(parameters, int32_t));
set_register(r1, va_arg(parameters, int32_t));
set_register(r2, va_arg(parameters, int32_t));
set_register(r3, 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));
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] = 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(lr, 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 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.
CHECK_EQ(callee_saved_value, get_register(r4));
CHECK_EQ(callee_saved_value, get_register(r5));
CHECK_EQ(callee_saved_value, get_register(r6));
CHECK_EQ(callee_saved_value, get_register(r7));
CHECK_EQ(callee_saved_value, get_register(r8));
CHECK_EQ(callee_saved_value, get_register(r9));
CHECK_EQ(callee_saved_value, get_register(r10));
CHECK_EQ(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);
// Pop stack passed arguments.
CHECK_EQ(entry_stack, get_register(sp));
set_register(sp, original_stack);
int32_t result = get_register(r0);
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;
}
} } // namespace assembler::arm
#endif // __arm__
#endif // V8_TARGET_ARCH_ARM
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