assembler-ia32.cc.svn-base

Google浏览器V8内核代码

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void Assembler::test(Register reg, const Immediate& imm) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  // Only use test against byte for registers that have a byte
  // variant: eax, ebx, ecx, and edx.
  if (imm.rmode_ == RelocInfo::NONE && is_uint8(imm.x_) && reg.code() < 4) {
    uint8_t imm8 = imm.x_;
    if (reg.is(eax)) {
      EMIT(0xA8);
      EMIT(imm8);
    } else {
      emit_arith_b(0xF6, 0xC0, reg, imm8);
    }
  } else {
    // This is not using emit_arith because test doesn't support
    // sign-extension of 8-bit operands.
    if (reg.is(eax)) {
      EMIT(0xA9);
    } else {
      EMIT(0xF7);
      EMIT(0xC0 | reg.code());
    }
    emit(imm);
  }
}


void Assembler::test(Register reg, const Operand& op) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0x85);
  emit_operand(reg, op);
}


void Assembler::test(const Operand& op, const Immediate& imm) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0xF7);
  emit_operand(eax, op);
  emit(imm);
}


void Assembler::xor_(Register dst, int32_t imm32) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  emit_arith(6, Operand(dst), Immediate(imm32));
}


void Assembler::xor_(Register dst, const Operand& src) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0x33);
  emit_operand(dst, src);
}


void Assembler::xor_(const Operand& src, Register dst) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0x31);
  emit_operand(dst, src);
}


void Assembler::xor_(const Operand& dst, const Immediate& x) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  emit_arith(6, dst, x);
}


void Assembler::bts(const Operand& dst, Register src) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0x0F);
  EMIT(0xAB);
  emit_operand(src, dst);
}


void Assembler::hlt() {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0xF4);
}


void Assembler::int3() {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0xCC);
}


void Assembler::nop() {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0x90);
}


void Assembler::rdtsc() {
  ASSERT(CpuFeatures::IsEnabled(CpuFeatures::RDTSC));
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0x0F);
  EMIT(0x31);
}


void Assembler::ret(int imm16) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  ASSERT(is_uint16(imm16));
  if (imm16 == 0) {
    EMIT(0xC3);
  } else {
    EMIT(0xC2);
    EMIT(imm16 & 0xFF);
    EMIT((imm16 >> 8) & 0xFF);
  }
}


void Assembler::leave() {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0xC9);
}


// Labels refer to positions in the (to be) generated code.
// There are bound, linked, and unused labels.
//
// Bound labels refer to known positions in the already
// generated code. pos() is the position the label refers to.
//
// Linked labels refer to unknown positions in the code
// to be generated; pos() is the position of the 32bit
// Displacement of the last instruction using the label.


void Assembler::print(Label* L) {
  if (L->is_unused()) {
    PrintF("unused label\n");
  } else if (L->is_bound()) {
    PrintF("bound label to %d\n", L->pos());
  } else if (L->is_linked()) {
    Label l = *L;
    PrintF("unbound label");
    while (l.is_linked()) {
      Displacement disp = disp_at(&l);
      PrintF("@ %d ", l.pos());
      disp.print();
      PrintF("\n");
      disp.next(&l);
    }
  } else {
    PrintF("label in inconsistent state (pos = %d)\n", L->pos_);
  }
}


void Assembler::bind_to(Label* L, int pos) {
  EnsureSpace ensure_space(this);
  last_pc_ = NULL;
  ASSERT(0 <= pos && pos <= pc_offset());  // must have a valid binding position
  while (L->is_linked()) {
    Displacement disp = disp_at(L);
    int fixup_pos = L->pos();
    if (disp.type() == Displacement::UNCONDITIONAL_JUMP) {
      ASSERT(byte_at(fixup_pos - 1) == 0xE9);  // jmp expected
    }
    // relative address, relative to point after address
    int imm32 = pos - (fixup_pos + sizeof(int32_t));
    long_at_put(fixup_pos, imm32);
    disp.next(L);
  }
  L->bind_to(pos);

  // do not eliminate jump instructions before the last bound position
  if (pos > last_bound_pos_)
    last_bound_pos_ = pos;
}


void Assembler::link_to(Label* L, Label* appendix) {
  EnsureSpace ensure_space(this);
  last_pc_ = NULL;
  if (appendix->is_linked()) {
    if (L->is_linked()) {
      // append appendix to L's list
      Label p;
      Label q = *L;
      do {
        p = q;
        Displacement disp = disp_at(&q);
        disp.next(&q);
      } while (q.is_linked());
      Displacement disp = disp_at(&p);
      disp.link_to(appendix);
      disp_at_put(&p, disp);
      p.Unuse();  // to avoid assertion failure in ~Label
    } else {
      // L is empty, simply use appendix
      *L = *appendix;
    }
  }
  appendix->Unuse();  // appendix should not be used anymore
}


void Assembler::bind(Label* L) {
  EnsureSpace ensure_space(this);
  last_pc_ = NULL;
  ASSERT(!L->is_bound());  // label can only be bound once
  if (FLAG_eliminate_jumps) {
    // Resolve unbound label.
    if (unbound_label_.is_linked()) {
      // Unbound label exists => link it with L if same binding
      // position, otherwise fix it.
      if (binding_pos_ == pc_offset()) {
        // Link it to L's list.
        link_to(L, &unbound_label_);
      } else {
        // Otherwise bind unbound label.
        ASSERT(binding_pos_ < pc_offset());
        bind_to(&unbound_label_, binding_pos_);
      }
    }
    ASSERT(!unbound_label_.is_linked());
    // try to eliminate jumps to next instruction
    const int absolute_jump_size = 5;
    // Do not remove an already bound jump target.
    while (last_bound_pos_ < pc_offset() &&
           reloc_info_writer.last_pc() <= pc_ - absolute_jump_size &&
           L->is_linked() &&
           (L->pos() + static_cast<int>(sizeof(int32_t)) == pc_offset()) &&
           (disp_at(L).type() == Displacement::UNCONDITIONAL_JUMP)) {
      // Previous instruction is jump jumping immediately after it =>
      // eliminate it.
      // jmp expected.
      ASSERT(byte_at(pc_offset() - absolute_jump_size) == 0xE9);
      if (FLAG_print_jump_elimination) {
        PrintF("@ %d jump to next eliminated\n", L->pos());
      }
      // Remove first entry from label list.
      Displacement disp = disp_at(L);
      disp.next(L);
      // Eliminate instruction (set code pointers back).
      pc_ -= absolute_jump_size;
      // Make sure not to skip relocation information when rewinding.
      ASSERT(reloc_info_writer.last_pc() <= pc_);
    }
    // Delay fixup of L => store it as unbound label.
    unbound_label_ = *L;
    binding_pos_ = pc_offset();
    L->Unuse();
  }
  bind_to(L, pc_offset());
}


void Assembler::call(Label* L) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  if (L->is_bound()) {
    const int long_size = 5;
    int offs = L->pos() - pc_offset();
    ASSERT(offs <= 0);
    // 1110 1000 #32-bit disp
    EMIT(0xE8);
    emit(offs - long_size);
  } else {
    // 1110 1000 #32-bit disp
    EMIT(0xE8);
    emit_disp(L, Displacement::OTHER);
  }
}


void Assembler::call(byte* entry, RelocInfo::Mode rmode) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  ASSERT(!RelocInfo::IsCodeTarget(rmode));
  EMIT(0xE8);
  emit(entry - (pc_ + sizeof(int32_t)), rmode);
}


void Assembler::call(const Operand& adr) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0xFF);
  emit_operand(edx, adr);
}


void Assembler::call(Handle<Code> code,  RelocInfo::Mode rmode) {
  WriteRecordedPositions();
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  ASSERT(RelocInfo::IsCodeTarget(rmode));
  EMIT(0xE8);
  emit(reinterpret_cast<intptr_t>(code.location()), rmode);
}


void Assembler::jmp(Label* L) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  if (L->is_bound()) {
    const int short_size = 2;
    const int long_size  = 5;
    int offs = L->pos() - pc_offset();
    ASSERT(offs <= 0);
    if (is_int8(offs - short_size)) {
      // 1110 1011 #8-bit disp
      EMIT(0xEB);
      EMIT((offs - short_size) & 0xFF);
    } else {
      // 1110 1001 #32-bit disp
      EMIT(0xE9);
      emit(offs - long_size);
    }
  } else {
    if (FLAG_eliminate_jumps &&
        unbound_label_.is_linked() &&
        binding_pos_ == pc_offset()) {
      // Current position is target of jumps
      if (FLAG_print_jump_elimination) {
        PrintF("eliminated jumps/calls to %d from ", binding_pos_);
        print(&unbound_label_);
      }
      link_to(L, &unbound_label_);
    }
    // 1110 1001 #32-bit disp
    EMIT(0xE9);
    emit_disp(L, Displacement::UNCONDITIONAL_JUMP);
  }
}


void Assembler::jmp(byte* entry, RelocInfo::Mode rmode) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  ASSERT(!RelocInfo::IsCodeTarget(rmode));
  EMIT(0xE9);
  emit(entry - (pc_ + sizeof(int32_t)), rmode);
}


void Assembler::jmp(const Operand& adr) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0xFF);
  emit_operand(esp, adr);
}


void Assembler::jmp(Handle<Code> code, RelocInfo::Mode rmode) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  ASSERT(RelocInfo::IsCodeTarget(rmode));
  EMIT(0xE9);
  emit(reinterpret_cast<intptr_t>(code.location()), rmode);
}



void Assembler::j(Condition cc, Label* L, Hint hint) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  ASSERT(0 <= cc && cc < 16);
  if (FLAG_emit_branch_hints && hint != no_hint) EMIT(hint);
  if (L->is_bound()) {
    const int short_size = 2;
    const int long_size  = 6;
    int offs = L->pos() - pc_offset();
    ASSERT(offs <= 0);
    if (is_int8(offs - short_size)) {
      // 0111 tttn #8-bit disp
      EMIT(0x70 | cc);
      EMIT((offs - short_size) & 0xFF);
    } else {
      // 0000 1111 1000 tttn #32-bit disp
      EMIT(0x0F);
      EMIT(0x80 | cc);
      emit(offs - long_size);
    }
  } else {
    // 0000 1111 1000 tttn #32-bit disp
    // Note: could eliminate cond. jumps to this jump if condition
    //       is the same however, seems to be rather unlikely case.
    EMIT(0x0F);
    EMIT(0x80 | cc);
    emit_disp(L, Displacement::OTHER);
  }
}


void Assembler::j(Condition cc, byte* entry, RelocInfo::Mode rmode, Hint hint) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  ASSERT((0 <= cc) && (cc < 16));
  if (FLAG_emit_branch_hints && hint != no_hint) EMIT(hint);
  // 0000 1111 1000 tttn #32-bit disp
  EMIT(0x0F);
  EMIT(0x80 | cc);
  emit(entry - (pc_ + sizeof(int32_t)), rmode);
}


void Assembler::j(Condition cc, Handle<Code> code, Hint hint) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  if (FLAG_emit_branch_hints && hint != no_hint) EMIT(hint);
  // 0000 1111 1000 tttn #32-bit disp
  EMIT(0x0F);
  EMIT(0x80 | cc);
  emit(reinterpret_cast<intptr_t>(code.location()), RelocInfo::CODE_TARGET);
}


// FPU instructions


void Assembler::fld(int i) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  emit_farith(0xD9, 0xC0, i);
}


void Assembler::fld1() {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0xD9);
  EMIT(0xE8);
}


void Assembler::fldz() {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0xD9);
  EMIT(0xEE);
}


void Assembler::fld_s(const Operand& adr) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0xD9);
  emit_operand(eax, adr);
}


void Assembler::fld_d(const Operand& adr) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0xDD);
  emit_operand(eax, adr);
}


void Assembler::fstp_s(const Operand& adr) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0xD9);
  emit_operand(ebx, adr);
}


void Assembler::fstp_d(const Operand& adr) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0xDD);
  emit_operand(ebx, adr);
}


void Assembler::fild_s(const Operand& adr) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0xDB);
  emit_operand(eax, adr);
}


void Assembler::fild_d(const Operand& adr) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0xDF);
  emit_operand(ebp, adr);
}


void Assembler::fistp_s(const Operand& adr) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0xDB);
  emit_operand(ebx, adr);
}


void Assembler::fist_s(const Operand& adr) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;
  EMIT(0xDB);
  emit_operand(edx, adr);
}


void Assembler::fistp_d(const Operand& adr) {
  EnsureSpace ensure_space(this);
  last_pc_ = pc_;