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Diffstat (limited to 'src/arch/alpha/isa/fp.isa')
| -rw-r--r-- | src/arch/alpha/isa/fp.isa | 301 |
1 files changed, 301 insertions, 0 deletions
diff --git a/src/arch/alpha/isa/fp.isa b/src/arch/alpha/isa/fp.isa new file mode 100644 index 000000000..f34c13c42 --- /dev/null +++ b/src/arch/alpha/isa/fp.isa @@ -0,0 +1,301 @@ +// -*- 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. + +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. +#if FULL_SYSTEM + inline Fault checkFpEnableFault(%(CPU_exec_context)s *xc) + { + Fault fault = NoFault; // dummy... this ipr access should not fault + if (!EV5::ICSR_FPE(xc->readMiscRegWithEffect(AlphaISA::IPR_ICSR, fault))) { + fault = new FloatEnableFault; + } + return fault; + } +#else + inline Fault checkFpEnableFault(%(CPU_exec_context)s *xc) + { + return NoFault; + } +#endif +}}; + +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; + }; + +}}; + + +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] >= FP_Base_DepTag) + ? 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[] = { + FE_TOWARDZERO, // Chopped + FE_DOWNWARD, // Minus_Infinity + FE_TONEAREST, // Normal + 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(%(CPU_exec_context)s *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 { + fesetround(getC99RoundingMode( + xc->readMiscReg(AlphaISA::Fpcr_DepTag))); + %(code)s; + fesetround(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(%(CPU_exec_context)s *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', CodeBlock(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', CodeBlock(code), opt_args) + decode_block = FloatingPointDecode.subst(iop) + header_output = BasicDeclare.subst(iop) + decoder_output = BasicConstructor.subst(iop) + exec_output = FPFixedRoundingExecute.subst(iop) +}}; + |