MIPS port initial commit

src/mips/constants-mips.h

+// 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.
+
+#ifndef  V8_MIPS_CONSTANTS_H_
+#define  V8_MIPS_CONSTANTS_H_
+
+#include "checks.h"
+
+// UNIMPLEMENTED_ macro for MIPS.
+#define UNIMPLEMENTED_MIPS()                                                  \
+  v8::internal::PrintF("%s, \tline %d: \tfunction %s not implemented. \n",    \
+                       __FILE__, __LINE__, __func__)
+#define UNSUPPORTED_MIPS() v8::internal::PrintF("Unsupported instruction.\n")
+
+
+// Defines constants and accessor classes to assemble, disassemble and
+// simulate MIPS32 instructions.
+//
+// See: MIPS32 Architecture For Programmers
+//      Volume II: The MIPS32 Instruction Set
+// Try www.cs.cornell.edu/courses/cs3410/2008fa/MIPS_Vol2.pdf.
+
+namespace assembler {
+namespace mips {
+
+// -----------------------------------------------------------------------------
+// Registers and FPURegister.
+
+// Number of general purpose registers.
+static const int kNumRegisters = 32;
+static const int kInvalidRegister = -1;
+
+// Number of registers with HI, LO, and pc.
+static const int kNumSimuRegisters = 35;
+
+// In the simulator, the PC register is simulated as the 34th register.
+static const int kPCRegister = 34;
+
+// Number coprocessor registers.
+static const int kNumFPURegister = 32;
+static const int kInvalidFPURegister = -1;
+
+// Helper functions for converting between register numbers and names.
+class Registers {
+ public:
+  // Return the name of the register.
+  static const char* Name(int reg);
+
+  // Lookup the register number for the name provided.
+  static int Number(const char* name);
+
+  struct RegisterAlias {
+    int reg;
+    const char *name;
+  };
+
+  static const int32_t kMaxValue = 0x7fffffff;
+  static const int32_t kMinValue = 0x80000000;
+
+ private:
+
+  static const char* names_[kNumSimuRegisters];
+  static const RegisterAlias aliases_[];
+};
+
+// Helper functions for converting between register numbers and names.
+class FPURegister {
+ public:
+  // Return the name of the register.
+  static const char* Name(int reg);
+
+  // Lookup the register number for the name provided.
+  static int Number(const char* name);
+
+  struct RegisterAlias {
+    int creg;
+    const char *name;
+  };
+
+ private:
+
+  static const char* names_[kNumFPURegister];
+  static const RegisterAlias aliases_[];
+};
+
+
+// -----------------------------------------------------------------------------
+// Instructions encoding constants.
+
+// On MIPS all instructions are 32 bits.
+typedef int32_t Instr;
+
+typedef unsigned char byte_;
+
+// Special Software Interrupt codes when used in the presence of the MIPS
+// simulator.
+enum SoftwareInterruptCodes {
+  // Transition to C code.
+  call_rt_redirected = 0xfffff
+};
+
+// ----- Fields offset and length.
+static const int kOpcodeShift   = 26;
+static const int kOpcodeBits    = 6;
+static const int kRsShift       = 21;
+static const int kRsBits        = 5;
+static const int kRtShift       = 16;
+static const int kRtBits        = 5;
+static const int kRdShift       = 11;
+static const int kRdBits        = 5;
+static const int kSaShift       = 6;
+static const int kSaBits        = 5;
+static const int kFunctionShift = 0;
+static const int kFunctionBits  = 6;
+
+static const int kImm16Shift = 0;
+static const int kImm16Bits  = 16;
+static const int kImm26Shift = 0;
+static const int kImm26Bits  = 26;
+
+static const int kFsShift       = 11;
+static const int kFsBits        = 5;
+static const int kFtShift       = 16;
+static const int kFtBits        = 5;
+
+// ----- Miscellianous useful masks.
+// Instruction bit masks.
+static const int  kOpcodeMask   = ((1 << kOpcodeBits) - 1) << kOpcodeShift;
+static const int  kImm16Mask    = ((1 << kImm16Bits) - 1) << kImm16Shift;
+static const int  kImm26Mask    = ((1 << kImm26Bits) - 1) << kImm26Shift;
+static const int  kRsFieldMask  = ((1 << kRsBits) - 1) << kRsShift;
+static const int  kRtFieldMask  = ((1 << kRtBits) - 1) << kRtShift;
+static const int  kRdFieldMask  = ((1 << kRdBits) - 1) << kRdShift;
+static const int  kSaFieldMask  = ((1 << kSaBits) - 1) << kSaShift;
+static const int  kFunctionFieldMask =
+    ((1 << kFunctionBits) - 1) << kFunctionShift;
+// Misc masks.
+static const int  HIMask        =   0xffff << 16;
+static const int  LOMask        =   0xffff;
+static const int  signMask      =   0x80000000;
+
+
+// ----- MIPS Opcodes and Function Fields.
+// We use this presentation to stay close to the table representation in
+// MIPS32 Architecture For Programmers, Volume II: The MIPS32 Instruction Set.
+enum Opcode {
+  SPECIAL   =   0 << kOpcodeShift,
+  REGIMM    =   1 << kOpcodeShift,
+
+  J         =   ((0 << 3) + 2) << kOpcodeShift,
+  JAL       =   ((0 << 3) + 3) << kOpcodeShift,
+  BEQ       =   ((0 << 3) + 4) << kOpcodeShift,
+  BNE       =   ((0 << 3) + 5) << kOpcodeShift,
+  BLEZ      =   ((0 << 3) + 6) << kOpcodeShift,
+  BGTZ      =   ((0 << 3) + 7) << kOpcodeShift,
+
+  ADDI      =   ((1 << 3) + 0) << kOpcodeShift,
+  ADDIU     =   ((1 << 3) + 1) << kOpcodeShift,
+  SLTI      =   ((1 << 3) + 2) << kOpcodeShift,
+  SLTIU     =   ((1 << 3) + 3) << kOpcodeShift,
+  ANDI      =   ((1 << 3) + 4) << kOpcodeShift,
+  ORI       =   ((1 << 3) + 5) << kOpcodeShift,
+  XORI      =   ((1 << 3) + 6) << kOpcodeShift,
+  LUI       =   ((1 << 3) + 7) << kOpcodeShift,
+
+  COP1      =   ((2 << 3) + 1) << kOpcodeShift,  // Coprocessor 1 class
+  BEQL      =   ((2 << 3) + 4) << kOpcodeShift,
+  BNEL      =   ((2 << 3) + 5) << kOpcodeShift,
+  BLEZL     =   ((2 << 3) + 6) << kOpcodeShift,
+  BGTZL     =   ((2 << 3) + 7) << kOpcodeShift,
+
+  SPECIAL2  =   ((3 << 3) + 4) << kOpcodeShift,
+
+  LB        =   ((4 << 3) + 0) << kOpcodeShift,
+  LW        =   ((4 << 3) + 3) << kOpcodeShift,
+  LBU       =   ((4 << 3) + 4) << kOpcodeShift,
+  SB        =   ((5 << 3) + 0) << kOpcodeShift,
+  SW        =   ((5 << 3) + 3) << kOpcodeShift,
+
+  LWC1      =   ((6 << 3) + 1) << kOpcodeShift,
+  LDC1      =   ((6 << 3) + 5) << kOpcodeShift,
+
+  SWC1      =   ((7 << 3) + 1) << kOpcodeShift,
+  SDC1      =   ((7 << 3) + 5) << kOpcodeShift
+};
+
+enum SecondaryField {
+  // SPECIAL Encoding of Function Field.
+  SLL       =   ((0 << 3) + 0),
+  SRL       =   ((0 << 3) + 2),
+  SRA       =   ((0 << 3) + 3),
+  SLLV      =   ((0 << 3) + 4),
+  SRLV      =   ((0 << 3) + 6),
+  SRAV      =   ((0 << 3) + 7),
+
+  JR        =   ((1 << 3) + 0),
+  JALR      =   ((1 << 3) + 1),
+  BREAK     =   ((1 << 3) + 5),
+
+  MFHI      =   ((2 << 3) + 0),
+  MFLO      =   ((2 << 3) + 2),
+
+  MULT      =   ((3 << 3) + 0),
+  MULTU     =   ((3 << 3) + 1),
+  DIV       =   ((3 << 3) + 2),
+  DIVU      =   ((3 << 3) + 3),
+
+  ADD       =   ((4 << 3) + 0),
+  ADDU      =   ((4 << 3) + 1),
+  SUB       =   ((4 << 3) + 2),
+  SUBU      =   ((4 << 3) + 3),
+  AND       =   ((4 << 3) + 4),
+  OR        =   ((4 << 3) + 5),
+  XOR       =   ((4 << 3) + 6),
+  NOR       =   ((4 << 3) + 7),
+
+  SLT       =   ((5 << 3) + 2),
+  SLTU      =   ((5 << 3) + 3),
+
+  TGE       =   ((6 << 3) + 0),
+  TGEU      =   ((6 << 3) + 1),
+  TLT       =   ((6 << 3) + 2),
+  TLTU      =   ((6 << 3) + 3),
+  TEQ       =   ((6 << 3) + 4),
+  TNE       =   ((6 << 3) + 6),
+
+  // SPECIAL2 Encoding of Function Field.
+  MUL       =   ((0 << 3) + 2),
+
+  // REGIMM  encoding of rt Field.
+  BLTZ      =   ((0 << 3) + 0) << 16,
+  BGEZ      =   ((0 << 3) + 1) << 16,
+  BLTZAL    =   ((2 << 3) + 0) << 16,
+  BGEZAL    =   ((2 << 3) + 1) << 16,
+
+  // COP1 Encoding of rs Field.
+  MFC1      =   ((0 << 3) + 0) << 21,
+  MFHC1     =   ((0 << 3) + 3) << 21,
+  MTC1      =   ((0 << 3) + 4) << 21,
+  MTHC1     =   ((0 << 3) + 7) << 21,
+  BC1       =   ((1 << 3) + 0) << 21,
+  S         =   ((2 << 3) + 0) << 21,
+  D         =   ((2 << 3) + 1) << 21,
+  W         =   ((2 << 3) + 4) << 21,
+  L         =   ((2 << 3) + 5) << 21,
+  PS        =   ((2 << 3) + 6) << 21,
+  // COP1 Encoding of Function Field When rs=S.
+  CVT_D_S   =   ((4 << 3) + 1),
+  CVT_W_S   =   ((4 << 3) + 4),
+  CVT_L_S   =   ((4 << 3) + 5),
+  CVT_PS_S  =   ((4 << 3) + 6),
+  // COP1 Encoding of Function Field When rs=D.
+  CVT_S_D   =   ((4 << 3) + 0),
+  CVT_W_D   =   ((4 << 3) + 4),
+  CVT_L_D   =   ((4 << 3) + 5),
+  // COP1 Encoding of Function Field When rs=W or L.
+  CVT_S_W   =   ((4 << 3) + 0),
+  CVT_D_W   =   ((4 << 3) + 1),
+  CVT_S_L   =   ((4 << 3) + 0),
+  CVT_D_L   =   ((4 << 3) + 1),
+  // COP1 Encoding of Function Field When rs=PS.
+
+  NULLSF    =   0
+};
+
+
+// ----- Emulated conditions.
+// On MIPS we use this enum to abstract from conditionnal branch instructions.
+// the 'U' prefix is used to specify unsigned comparisons.
+enum Condition {
+  // Any value < 0 is considered no_condition.
+  no_condition  = -1,
+
+  overflow      =  0,
+  no_overflow   =  1,
+  Uless         =  2,
+  Ugreater_equal=  3,
+  equal         =  4,
+  not_equal     =  5,
+  Uless_equal   =  6,
+  Ugreater      =  7,
+  negative      =  8,
+  positive      =  9,
+  parity_even   = 10,
+  parity_odd    = 11,
+  less          = 12,
+  greater_equal = 13,
+  less_equal    = 14,
+  greater       = 15,
+
+  cc_always     = 16,
+
+  // aliases
+  carry         = Uless,
+  not_carry     = Ugreater_equal,
+  zero          = equal,
+  eq            = equal,
+  not_zero      = not_equal,
+  ne            = not_equal,
+  sign          = negative,
+  not_sign      = positive,
+
+  cc_default    = no_condition
+};
+
+// ----- Coprocessor conditions.
+enum FPUCondition {
+  F,    // False
+  UN,   // Unordered
+  EQ,   // Equal
+  UEQ,  // Unordered or Equal
+  OLT,  // Ordered or Less Than
+  ULT,  // Unordered or Less Than
+  OLE,  // Ordered or Less Than or Equal
+  ULE   // Unordered or Less Than or Equal
+};
+
+
+// Break 0xfffff, reserved for redirected real time call.
+const Instr rtCallRedirInstr = SPECIAL | BREAK | call_rt_redirected << 6;
+// A nop instruction. (Encoding of sll 0 0 0).
+const Instr nopInstr = 0;
+
+class Instruction {
+ public:
+  enum {
+    kInstructionSize = 4,
+    kInstructionSizeLog2 = 2,
+    // On MIPS PC cannot actually be directly accessed. We behave as if PC was
+    // always the value of the current instruction being exectued.
+    kPCReadOffset = 0
+  };
+
+  // Get the raw instruction bits.
+  inline Instr InstructionBits() const {
+    return *reinterpret_cast<const Instr*>(this);
+  }
+
+  // Set the raw instruction bits to value.
+  inline void SetInstructionBits(Instr value) {
+    *reinterpret_cast<Instr*>(this) = value;
+  }
+
+  // Read one particular bit out of the instruction bits.
+  inline int Bit(int nr) const {
+    return (InstructionBits() >> nr) & 1;
+  }
+
+  // Read a bit field out of the instruction bits.
+  inline int Bits(int hi, int lo) const {
+    return (InstructionBits() >> lo) & ((2 << (hi - lo)) - 1);
+  }
+
+  // Instruction type.
+  enum Type {
+    kRegisterType,
+    kImmediateType,
+    kJumpType,
+    kUnsupported = -1
+  };
+
+  // Get the encoding type of the instruction.
+  Type InstructionType() const;
+
+
+  // Accessors for the different named fields used in the MIPS encoding.
+  inline Opcode OpcodeField() const {
+    return static_cast<Opcode>(
+        Bits(kOpcodeShift + kOpcodeBits - 1, kOpcodeShift));
+  }
+
+  inline int RsField() const {
+    ASSERT(InstructionType() == kRegisterType ||
+           InstructionType() == kImmediateType);
+    return Bits(kRsShift + kRsBits - 1, kRsShift);
+  }
+
+  inline int RtField() const {
+    ASSERT(InstructionType() == kRegisterType ||
+           InstructionType() == kImmediateType);
+    return Bits(kRtShift + kRtBits - 1, kRtShift);
+  }
+
+  inline int RdField() const {
+    ASSERT(InstructionType() == kRegisterType);
+    return Bits(kRdShift + kRdBits - 1, kRdShift);
+  }
+
+  inline int SaField() const {
+    ASSERT(InstructionType() == kRegisterType);
+    return Bits(kSaShift + kSaBits - 1, kSaShift);
+  }
+
+  inline int FunctionField() const {
+    ASSERT(InstructionType() == kRegisterType ||
+           InstructionType() == kImmediateType);
+    return Bits(kFunctionShift + kFunctionBits - 1, kFunctionShift);
+  }
+
+  inline int FsField() const {
+    return Bits(kFsShift + kRsBits - 1, kFsShift);
+  }
+
+  inline int FtField() const {
+    return Bits(kFtShift + kRsBits - 1, kFtShift);
+  }
+
+  // Return the fields at their original place in the instruction encoding.
+  inline Opcode OpcodeFieldRaw() const {
+    return static_cast<Opcode>(InstructionBits() & kOpcodeMask);
+  }
+
+  inline int RsFieldRaw() const {
+    ASSERT(InstructionType() == kRegisterType ||
+           InstructionType() == kImmediateType);
+    return InstructionBits() & kRsFieldMask;
+  }
+
+  inline int RtFieldRaw() const {
+    ASSERT(InstructionType() == kRegisterType ||
+           InstructionType() == kImmediateType);
+    return InstructionBits() & kRtFieldMask;
+  }
+
+  inline int RdFieldRaw() const {
+    ASSERT(InstructionType() == kRegisterType);
+    return InstructionBits() & kRdFieldMask;
+  }
+
+  inline int SaFieldRaw() const {
+    ASSERT(InstructionType() == kRegisterType);
+    return InstructionBits() & kSaFieldMask;
+  }
+
+  inline int FunctionFieldRaw() const {
+    return InstructionBits() & kFunctionFieldMask;
+  }
+
+  // Get the secondary field according to the opcode.
+  inline int SecondaryField() const {
+    Opcode op = OpcodeFieldRaw();
+    switch (op) {
+      case SPECIAL:
+      case SPECIAL2:
+        return FunctionField();
+      case COP1:
+        return RsField();
+      case REGIMM:
+        return RtField();
+      default:
+        return NULLSF;
+    }
+  }
+
+  inline int32_t Imm16Field() const {
+    ASSERT(InstructionType() == kImmediateType);
+    return Bits(kImm16Shift + kImm16Bits - 1, kImm16Shift);
+  }
+
+  inline int32_t Imm26Field() const {
+    ASSERT(InstructionType() == kJumpType);
+    return Bits(kImm16Shift + kImm26Bits - 1, kImm26Shift);
+  }
+
+  // Say if the instruction should not be used in a branch delay slot.
+  bool IsForbiddenInBranchDelay();
+  // Say if the instruction 'links'. eg: jal, bal.
+  bool IsLinkingInstruction();
+  // Say if the instruction is a break or a trap.
+  bool IsTrap();
+
+  // Instructions are read of out a code stream. The only way to get a
+  // reference to an instruction is to convert a pointer. There is no way
+  // to allocate or create instances of class Instruction.
+  // Use the At(pc) function to create references to Instruction.
+  static Instruction* At(byte_* pc) {
+    return reinterpret_cast<Instruction*>(pc);
+  }
+
+ private:
+  // We need to prevent the creation of instances of class Instruction.
+  DISALLOW_IMPLICIT_CONSTRUCTORS(Instruction);
+};
+
+
+// -----------------------------------------------------------------------------
+// MIPS assembly various constants.
+
+static const int kArgsSlotsSize  = 4 * Instruction::kInstructionSize;
+static const int kArgsSlotsNum   = 4;
+
+static const int kBranchReturnOffset = 2 * Instruction::kInstructionSize;
+
+static const int kDoubleAlignment = 2 * 8;
+static const int kDoubleAlignmentMask = kDoubleAlignmentMask - 1;
+
+
+} }   // namespace assembler::mips
+
+#endif    // #ifndef V8_MIPS_CONSTANTS_H_
+