src/arch/alpha/isa/fp.isa - amd/gem5 - Git at Google

 // -*- mode:c++ -*-

 // Copyright (c) 2003-2005 The Regents of The University of Michigan
 // 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 the copyright holders 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.
 //
 // Authors: Steve Reinhardt

 ////////////////////////////////////////////////////////////////////
 //
 // Floating-point instructions
 //
 //      Note that many FP-type instructions which do not support all the
 //      various rounding & trapping modes use the simpler format
 //      BasicOperateWithNopCheck.
 //

 output exec {{
     /// Check "FP enabled" machine status bit.  Called when executing any FP
     /// instruction in full-system mode.
     /// @retval Full-system mode: NoFault if FP is enabled, FenFault
     /// if not.  Non-full-system mode: always returns NoFault.
     inline Fault checkFpEnableFault(ExecContext *xc)
     {
         Fault fault = NoFault;  // dummy... this ipr access should not fault
         if (FullSystem && !ICSR_FPE(xc->readMiscReg(IPR_ICSR))) {
             fault = std::make_shared<FloatEnableFault>();
         }
         return fault;
     }
     inline Fault checkVectorEnableFault(ExecContext *xc) {
         return std::make_shared<VectorEnableFault>();
     }
 }};

 output header {{
     /**
      * Base class for general floating-point instructions.  Includes
      * support for various Alpha rounding and trapping modes.  Only FP
      * instructions that require this support are derived from this
      * class; the rest derive directly from AlphaStaticInst.
      */
     class AlphaFP : public AlphaStaticInst
     {
       public:
         /// Alpha FP rounding modes.
         enum RoundingMode {
             Chopped = 0,        ///< round toward zero
             Minus_Infinity = 1, ///< round toward minus infinity
             Normal = 2,         ///< round to nearest (default)
             Dynamic = 3,        ///< use FPCR setting (in instruction)
             Plus_Infinity = 3   ///< round to plus inifinity (in FPCR)
         };

         /// Alpha FP trapping modes.
         /// For instructions that produce integer results, the
         /// "Underflow Enable" modes really mean "Overflow Enable", and
         /// the assembly modifier is V rather than U.
         enum TrappingMode {
             /// default: nothing enabled
             Imprecise = 0,                 ///< no modifier
             /// underflow/overflow traps enabled, inexact disabled
             Underflow_Imprecise = 1,       ///< /U or /V
             Underflow_Precise = 5,         ///< /SU or /SV
             /// underflow/overflow and inexact traps enabled
             Underflow_Inexact_Precise = 7  ///< /SUI or /SVI
         };

       protected:
         /// Map Alpha rounding mode to C99 constants from <fenv.h>.
         static const int alphaToC99RoundingMode[];

         /// Map enum RoundingMode values to disassembly suffixes.
         static const char *roundingModeSuffix[];
         /// Map enum TrappingMode values to FP disassembly suffixes.
         static const char *fpTrappingModeSuffix[];
         /// Map enum TrappingMode values to integer disassembly suffixes.
         static const char *intTrappingModeSuffix[];

         /// This instruction's rounding mode.
         RoundingMode roundingMode;
         /// This instruction's trapping mode.
         TrappingMode trappingMode;

         /// Have we warned about this instruction's unsupported
         /// rounding mode (if applicable)?
         mutable bool warnedOnRounding;

         /// Have we warned about this instruction's unsupported
         /// trapping mode (if applicable)?
         mutable bool warnedOnTrapping;

         /// Constructor
         AlphaFP(const char *mnem, ExtMachInst _machInst, OpClass __opClass)
             : AlphaStaticInst(mnem, _machInst, __opClass),
               roundingMode((enum RoundingMode)FP_ROUNDMODE),
               trappingMode((enum TrappingMode)FP_TRAPMODE),
               warnedOnRounding(false),
               warnedOnTrapping(false)
         {
         }

         int getC99RoundingMode(uint64_t fpcr_val) const;

         // This differs from the AlphaStaticInst version only in
         // printing suffixes for non-default rounding & trapping modes.
         std::string generateDisassembly(
                 Addr pc, const SymbolTable *symtab) const override;
     };

 }};


 output decoder {{
     int
     AlphaFP::getC99RoundingMode(uint64_t fpcr_val) const
     {
         if (roundingMode == Dynamic) {
             return alphaToC99RoundingMode[bits(fpcr_val, 59, 58)];
         }
         else {
             return alphaToC99RoundingMode[roundingMode];
         }
     }

     std::string
     AlphaFP::generateDisassembly(Addr pc, const SymbolTable *symtab) const
     {
         std::string mnem_str(mnemonic);

 #ifndef SS_COMPATIBLE_DISASSEMBLY
         std::string suffix("");
         suffix += ((_destRegIdx[0].isFloatReg())
                    ? fpTrappingModeSuffix[trappingMode]
                    : intTrappingModeSuffix[trappingMode]);
         suffix += roundingModeSuffix[roundingMode];

         if (suffix != "") {
             mnem_str = csprintf("%s/%s", mnemonic, suffix);
         }
 #endif

         std::stringstream ss;
         ccprintf(ss, "%-10s ", mnem_str.c_str());

         // just print the first two source regs... if there's
         // a third one, it's a read-modify-write dest (Rc),
         // e.g. for CMOVxx
         if (_numSrcRegs > 0) {
             printReg(ss, _srcRegIdx[0]);
         }
         if (_numSrcRegs > 1) {
             ss << ",";
             printReg(ss, _srcRegIdx[1]);
         }

         // just print the first dest... if there's a second one,
         // it's generally implicit
         if (_numDestRegs > 0) {
             if (_numSrcRegs > 0)
                 ss << ",";
             printReg(ss, _destRegIdx[0]);
         }

         return ss.str();
     }

     const int AlphaFP::alphaToC99RoundingMode[] = {
         M5_FE_TOWARDZERO,       // Chopped
         M5_FE_DOWNWARD, // Minus_Infinity
         M5_FE_TONEAREST,        // Normal
         M5_FE_UPWARD    // Dynamic in inst, Plus_Infinity in FPCR
     };

     const char *AlphaFP::roundingModeSuffix[] = { "c", "m", "", "d" };
     // mark invalid trapping modes, but don't fail on them, because
     // you could decode anything on a misspeculated path
     const char *AlphaFP::fpTrappingModeSuffix[] =
         { "", "u", "INVTM2", "INVTM3", "INVTM4", "su", "INVTM6", "sui" };
     const char *AlphaFP::intTrappingModeSuffix[] =
         { "", "v", "INVTM2", "INVTM3", "INVTM4", "sv", "INVTM6", "svi" };
 }};

 // FP instruction class execute method template.  Handles non-standard
 // rounding modes.
 def template FloatingPointExecute {{
     Fault %(class_name)s::execute(ExecContext *xc,
                                   Trace::InstRecord *traceData) const
     {
         if (trappingMode != Imprecise && !warnedOnTrapping) {
             warn("%s: non-standard trapping mode not supported",
                  generateDisassembly(0, NULL));
             warnedOnTrapping = true;
         }

         Fault fault = NoFault;

         %(fp_enable_check)s;
         %(op_decl)s;
         %(op_rd)s;
 #if USE_FENV
         if (roundingMode == Normal) {
             %(code)s;
         } else {
             m5_fesetround(getC99RoundingMode(
                            xc->readMiscReg(MISCREG_FPCR)));
             %(code)s;
             m5_fesetround(M5_FE_TONEAREST);
         }
 #else
         if (roundingMode != Normal && !warnedOnRounding) {
             warn("%s: non-standard rounding mode not supported",
                  generateDisassembly(0, NULL));
             warnedOnRounding = true;
         }
         %(code)s;
 #endif

         if (fault == NoFault) {
             %(op_wb)s;
         }

         return fault;
     }
 }};

 // FP instruction class execute method template where no dynamic
 // rounding mode control is needed.  Like BasicExecute, but includes
 // check & warning for non-standard trapping mode.
 def template FPFixedRoundingExecute {{
     Fault %(class_name)s::execute(ExecContext *xc,
                                   Trace::InstRecord *traceData) const
     {
         if (trappingMode != Imprecise && !warnedOnTrapping) {
             warn("%s: non-standard trapping mode not supported",
                  generateDisassembly(0, NULL));
             warnedOnTrapping = true;
         }

         Fault fault = NoFault;

         %(fp_enable_check)s;
         %(op_decl)s;
         %(op_rd)s;
         %(code)s;

         if (fault == NoFault) {
             %(op_wb)s;
         }

         return fault;
     }
 }};

 def template FloatingPointDecode {{
  {
      AlphaStaticInst *i = new %(class_name)s(machInst);
      if (FC == 31) {
          i = makeNop(i);
      }
      return i;
  }
 }};

 // General format for floating-point operate instructions:
 // - Checks trapping and rounding mode flags.  Trapping modes
 //   currently unimplemented (will fail).
 // - Generates NOP if FC == 31.
 def format FloatingPointOperate(code, *opt_args) {{
     iop = InstObjParams(name, Name, 'AlphaFP', code, opt_args)
     decode_block = FloatingPointDecode.subst(iop)
     header_output = BasicDeclare.subst(iop)
     decoder_output = BasicConstructor.subst(iop)
     exec_output = FloatingPointExecute.subst(iop)
 }};

 // Special format for cvttq where rounding mode is pre-decoded
 def format FPFixedRounding(code, class_suffix, *opt_args) {{
     Name += class_suffix
     iop = InstObjParams(name, Name, 'AlphaFP', code, opt_args)
     decode_block = FloatingPointDecode.subst(iop)
     header_output = BasicDeclare.subst(iop)
     decoder_output = BasicConstructor.subst(iop)
     exec_output = FPFixedRoundingExecute.subst(iop)
 }};
	// -- mode:c++ --

	// Copyright (c) 2003-2005 The Regents of The University of Michigan
	// 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 the copyright holders 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.
	//
	// Authors: Steve Reinhardt

	////////////////////////////////////////////////////////////////////
	//
	// Floating-point instructions
	//
	// Note that many FP-type instructions which do not support all the
	// various rounding & trapping modes use the simpler format
	// BasicOperateWithNopCheck.
	//

	output exec {{
	/// Check "FP enabled" machine status bit. Called when executing any FP
	/// instruction in full-system mode.
	/// @retval Full-system mode: NoFault if FP is enabled, FenFault
	/// if not. Non-full-system mode: always returns NoFault.
	inline Fault checkFpEnableFault(ExecContext *xc)
	{
	Fault fault = NoFault; // dummy... this ipr access should not fault
	if (FullSystem && !ICSR_FPE(xc->readMiscReg(IPR_ICSR))) {
	fault = std::make_shared<FloatEnableFault>();
	}
	return fault;
	}
	inline Fault checkVectorEnableFault(ExecContext *xc) {
	return std::make_shared<VectorEnableFault>();
	}
	}};

	output header {{
	/**
	* Base class for general floating-point instructions. Includes
	* support for various Alpha rounding and trapping modes. Only FP
	* instructions that require this support are derived from this
	* class; the rest derive directly from AlphaStaticInst.
	*/
	class AlphaFP : public AlphaStaticInst
	{
	public:
	/// Alpha FP rounding modes.
	enum RoundingMode {
	Chopped = 0, ///< round toward zero
	Minus_Infinity = 1, ///< round toward minus infinity
	Normal = 2, ///< round to nearest (default)
	Dynamic = 3, ///< use FPCR setting (in instruction)
	Plus_Infinity = 3 ///< round to plus inifinity (in FPCR)
	};

	/// Alpha FP trapping modes.
	/// For instructions that produce integer results, the
	/// "Underflow Enable" modes really mean "Overflow Enable", and
	/// the assembly modifier is V rather than U.
	enum TrappingMode {
	/// default: nothing enabled
	Imprecise = 0, ///< no modifier
	/// underflow/overflow traps enabled, inexact disabled
	Underflow_Imprecise = 1, ///< /U or /V
	Underflow_Precise = 5, ///< /SU or /SV
	/// underflow/overflow and inexact traps enabled
	Underflow_Inexact_Precise = 7 ///< /SUI or /SVI
	};

	protected:
	/// Map Alpha rounding mode to C99 constants from <fenv.h>.
	static const int alphaToC99RoundingMode[];

	/// Map enum RoundingMode values to disassembly suffixes.
	static const char *roundingModeSuffix[];
	/// Map enum TrappingMode values to FP disassembly suffixes.
	static const char *fpTrappingModeSuffix[];
	/// Map enum TrappingMode values to integer disassembly suffixes.
	static const char *intTrappingModeSuffix[];

	/// This instruction's rounding mode.
	RoundingMode roundingMode;
	/// This instruction's trapping mode.
	TrappingMode trappingMode;

	/// Have we warned about this instruction's unsupported
	/// rounding mode (if applicable)?
	mutable bool warnedOnRounding;

	/// Have we warned about this instruction's unsupported
	/// trapping mode (if applicable)?
	mutable bool warnedOnTrapping;

	/// Constructor
	AlphaFP(const char *mnem, ExtMachInst _machInst, OpClass __opClass)
	: AlphaStaticInst(mnem, _machInst, __opClass),
	roundingMode((enum RoundingMode)FP_ROUNDMODE),
	trappingMode((enum TrappingMode)FP_TRAPMODE),
	warnedOnRounding(false),
	warnedOnTrapping(false)
	{
	}

	int getC99RoundingMode(uint64_t fpcr_val) const;

	// This differs from the AlphaStaticInst version only in
	// printing suffixes for non-default rounding & trapping modes.
	std::string generateDisassembly(
	Addr pc, const SymbolTable *symtab) const override;
	};

	}};


	output decoder {{
	int
	AlphaFP::getC99RoundingMode(uint64_t fpcr_val) const
	{
	if (roundingMode == Dynamic) {
	return alphaToC99RoundingMode[bits(fpcr_val, 59, 58)];
	}
	else {
	return alphaToC99RoundingMode[roundingMode];
	}
	}

	std::string
	AlphaFP::generateDisassembly(Addr pc, const SymbolTable *symtab) const
	{
	std::string mnem_str(mnemonic);

	#ifndef SS_COMPATIBLE_DISASSEMBLY
	std::string suffix("");
	suffix += ((_destRegIdx[0].isFloatReg())
	? fpTrappingModeSuffix[trappingMode]
	: intTrappingModeSuffix[trappingMode]);
	suffix += roundingModeSuffix[roundingMode];

	if (suffix != "") {
	mnem_str = csprintf("%s/%s", mnemonic, suffix);
	}
	#endif

	std::stringstream ss;
	ccprintf(ss, "%-10s ", mnem_str.c_str());

	// just print the first two source regs... if there's
	// a third one, it's a read-modify-write dest (Rc),
	// e.g. for CMOVxx
	if (_numSrcRegs > 0) {
	printReg(ss, _srcRegIdx[0]);
	}
	if (_numSrcRegs > 1) {
	ss << ",";
	printReg(ss, _srcRegIdx[1]);
	}

	// just print the first dest... if there's a second one,
	// it's generally implicit
	if (_numDestRegs > 0) {
	if (_numSrcRegs > 0)
	ss << ",";
	printReg(ss, _destRegIdx[0]);
	}

	return ss.str();
	}

	const int AlphaFP::alphaToC99RoundingMode[] = {
	M5_FE_TOWARDZERO, // Chopped
	M5_FE_DOWNWARD, // Minus_Infinity
	M5_FE_TONEAREST, // Normal
	M5_FE_UPWARD // Dynamic in inst, Plus_Infinity in FPCR
	};

	const char *AlphaFP::roundingModeSuffix[] = { "c", "m", "", "d" };
	// mark invalid trapping modes, but don't fail on them, because
	// you could decode anything on a misspeculated path
	const char *AlphaFP::fpTrappingModeSuffix[] =
	{ "", "u", "INVTM2", "INVTM3", "INVTM4", "su", "INVTM6", "sui" };
	const char *AlphaFP::intTrappingModeSuffix[] =
	{ "", "v", "INVTM2", "INVTM3", "INVTM4", "sv", "INVTM6", "svi" };
	}};

	// FP instruction class execute method template. Handles non-standard
	// rounding modes.
	def template FloatingPointExecute {{
	Fault %(class_name)s::execute(ExecContext *xc,
	Trace::InstRecord *traceData) const
	{
	if (trappingMode != Imprecise && !warnedOnTrapping) {
	warn("%s: non-standard trapping mode not supported",
	generateDisassembly(0, NULL));
	warnedOnTrapping = true;
	}

	Fault fault = NoFault;

	%(fp_enable_check)s;
	%(op_decl)s;
	%(op_rd)s;
	#if USE_FENV
	if (roundingMode == Normal) {
	%(code)s;
	} else {
	m5_fesetround(getC99RoundingMode(
	xc->readMiscReg(MISCREG_FPCR)));
	%(code)s;
	m5_fesetround(M5_FE_TONEAREST);
	}
	#else
	if (roundingMode != Normal && !warnedOnRounding) {
	warn("%s: non-standard rounding mode not supported",
	generateDisassembly(0, NULL));
	warnedOnRounding = true;
	}
	%(code)s;
	#endif

	if (fault == NoFault) {
	%(op_wb)s;
	}

	return fault;
	}
	}};

	// FP instruction class execute method template where no dynamic
	// rounding mode control is needed. Like BasicExecute, but includes
	// check & warning for non-standard trapping mode.
	def template FPFixedRoundingExecute {{
	Fault %(class_name)s::execute(ExecContext *xc,
	Trace::InstRecord *traceData) const
	{
	if (trappingMode != Imprecise && !warnedOnTrapping) {
	warn("%s: non-standard trapping mode not supported",
	generateDisassembly(0, NULL));
	warnedOnTrapping = true;
	}

	Fault fault = NoFault;

	%(fp_enable_check)s;
	%(op_decl)s;
	%(op_rd)s;
	%(code)s;

	if (fault == NoFault) {
	%(op_wb)s;
	}

	return fault;
	}
	}};

	def template FloatingPointDecode {{
	{
	AlphaStaticInst *i = new %(class_name)s(machInst);
	if (FC == 31) {
	i = makeNop(i);
	}
	return i;
	}
	}};

	// General format for floating-point operate instructions:
	// - Checks trapping and rounding mode flags. Trapping modes
	// currently unimplemented (will fail).
	// - Generates NOP if FC == 31.
	def format FloatingPointOperate(code, *opt_args) {{
	iop = InstObjParams(name, Name, 'AlphaFP', code, opt_args)
	decode_block = FloatingPointDecode.subst(iop)
	header_output = BasicDeclare.subst(iop)
	decoder_output = BasicConstructor.subst(iop)
	exec_output = FloatingPointExecute.subst(iop)
	}};

	// Special format for cvttq where rounding mode is pre-decoded
	def format FPFixedRounding(code, class_suffix, *opt_args) {{
	Name += class_suffix
	iop = InstObjParams(name, Name, 'AlphaFP', code, opt_args)
	decode_block = FloatingPointDecode.subst(iop)
	header_output = BasicDeclare.subst(iop)
	decoder_output = BasicConstructor.subst(iop)
	exec_output = FPFixedRoundingExecute.subst(iop)
	}};