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// -*- 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)
}};