From 28eefa5464ca6415fcee577d5c47f739535d7e6c Mon Sep 17 00:00:00 2001 From: Misha Brukman Date: Thu, 14 Oct 2004 05:53:01 +0000 Subject: * Factor out (into new fn) a loop emitting operand shifts into the instruction * Reverse instruction bit components for a LittleEndian-style encoding * Fix some comments and spacing git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16975 91177308-0d34-0410-b5e6-96231b3b80d8 --- utils/TableGen/CodeEmitterGen.cpp | 122 ++++++++++++++++++++++++-------------- 1 file changed, 76 insertions(+), 46 deletions(-) (limited to 'utils/TableGen/CodeEmitterGen.cpp') diff --git a/utils/TableGen/CodeEmitterGen.cpp b/utils/TableGen/CodeEmitterGen.cpp index dcf10672a3..a9e8261e25 100644 --- a/utils/TableGen/CodeEmitterGen.cpp +++ b/utils/TableGen/CodeEmitterGen.cpp @@ -19,6 +19,58 @@ #include "llvm/Support/Debug.h" using namespace llvm; +void CodeEmitterGen::emitInstrOpBits(std::ostream &o, + const std::vector &Vals, + std::map &OpOrder, + std::map &OpContinuous) +{ + for (unsigned f = 0, e = Vals.size(); f != e; ++f) { + if (Vals[f].getPrefix()) { + BitsInit *FieldInitializer = (BitsInit*)Vals[f].getValue(); + + // Scan through the field looking for bit initializers of the current + // variable... + for (int i = FieldInitializer->getNumBits()-1; i >= 0; --i) { + Init *I = FieldInitializer->getBit(i); + if (BitInit *BI = dynamic_cast(I)) { + DEBUG(o << " // bit init: f: " << f << ", i: " << i << "\n"); + } else if (UnsetInit *UI = dynamic_cast(I)) { + DEBUG(o << " // unset init: f: " << f << ", i: " << i << "\n"); + } else if (VarBitInit *VBI = dynamic_cast(I)) { + TypedInit *TI = VBI->getVariable(); + if (VarInit *VI = dynamic_cast(TI)) { + // If the bits of the field are laid out consecutively in the + // instruction, then instead of separately ORing in bits, just + // mask and shift the entire field for efficiency. + if (OpContinuous[VI->getName()]) { + // already taken care of in the loop above, thus there is no + // need to individually OR in the bits + + // for debugging, output the regular version anyway, commented + DEBUG(o << " // Value |= getValueBit(op" + << OpOrder[VI->getName()] << ", " << VBI->getBitNum() + << ")" << " << " << i << ";\n"); + } else { + o << " Value |= getValueBit(op" << OpOrder[VI->getName()] + << ", " << VBI->getBitNum() + << ")" << " << " << i << ";\n"; + } + } else if (FieldInit *FI = dynamic_cast(TI)) { + // FIXME: implement this! + std::cerr << "Error: FieldInit not implemented!\n"; + abort(); + } else { + std::cerr << "Error: unimplemented case in " + << "CodeEmitterGen::emitInstrOpBits()\n"; + abort(); + } + } + } + } + } +} + + void CodeEmitterGen::run(std::ostream &o) { CodeGenTarget Target; std::vector Insts = Records.getAllDerivedDefinitions("Instruction"); @@ -43,6 +95,24 @@ void CodeEmitterGen::run(std::ostream &o) { BitsInit *BI = R->getValueAsBitsInit("Inst"); + // For little-endian instruction bit encodings, reverse the bit order + if (Target.isLittleEndianEncoding()) { + unsigned numBits = BI->getNumBits(); + BitsInit *NewBI = new BitsInit(numBits); + for (unsigned bit = 0, end = numBits / 2; bit != end; ++bit) { + unsigned bitSwapIdx = numBits - bit - 1; + Init *OrigBit = BI->getBit(bit); + Init *BitSwap = BI->getBit(bitSwapIdx); + NewBI->setBit(bit, BitSwap); + NewBI->setBit(bitSwapIdx, OrigBit); + } + if (numBits % 2) { + unsigned middle = (numBits + 1) / 2; + NewBI->setBit(middle, BI->getBit(middle)); + } + BI = NewBI; + } + unsigned Value = 0; const std::vector &Vals = R->getValues(); @@ -61,17 +131,16 @@ void CodeEmitterGen::run(std::ostream &o) { DEBUG(o << " // " << *R->getValue("Inst") << "\n"); o << " Value = " << Value << "U;\n\n"; - // Loop over all of the fields in the instruction determining which are the + // Loop over all of the fields in the instruction, determining which are the // operands to the instruction. - // unsigned op = 0; std::map OpOrder; std::map OpContinuous; for (unsigned i = 0, e = Vals.size(); i != e; ++i) { - if (!Vals[i].getPrefix() && !Vals[i].getValue()->isComplete()) { + if (!Vals[i].getPrefix() && !Vals[i].getValue()->isComplete()) { // Is the operand continuous? If so, we can just mask and OR it in // instead of doing it bit-by-bit, saving a lot in runtime cost. - const BitsInit *InstInit = BI; + BitsInit *InstInit = BI; int beginBitInVar = -1, endBitInVar = -1; int beginBitInInst = -1, endBitInInst = -1; bool continuous = true; @@ -173,58 +242,19 @@ void CodeEmitterGen::run(std::ostream &o) { } } - for (unsigned f = 0, e = Vals.size(); f != e; ++f) { - if (Vals[f].getPrefix()) { - BitsInit *FieldInitializer = (BitsInit*)Vals[f].getValue(); - - // Scan through the field looking for bit initializers of the current - // variable... - for (int i = FieldInitializer->getNumBits()-1; i >= 0; --i) { - Init *I = FieldInitializer->getBit(i); - if (BitInit *BI = dynamic_cast(I)) { - DEBUG(o << " // bit init: f: " << f << ", i: " << i << "\n"); - } else if (UnsetInit *UI = dynamic_cast(I)) { - DEBUG(o << " // unset init: f: " << f << ", i: " << i << "\n"); - } else if (VarBitInit *VBI = dynamic_cast(I)) { - TypedInit *TI = VBI->getVariable(); - if (VarInit *VI = dynamic_cast(TI)) { - // If the bits of the field are laid out consecutively in the - // instruction, then instead of separately ORing in bits, just - // mask and shift the entire field for efficiency. - if (OpContinuous[VI->getName()]) { - // already taken care of in the loop above, thus there is no - // need to individually OR in the bits - - // for debugging, output the regular version anyway, commented - DEBUG(o << " // Value |= getValueBit(op" - << OpOrder[VI->getName()] << ", " << VBI->getBitNum() - << ")" << " << " << i << ";\n"); - } else { - o << " Value |= getValueBit(op" << OpOrder[VI->getName()] - << ", " << VBI->getBitNum() - << ")" << " << " << i << ";\n"; - } - } else if (FieldInit *FI = dynamic_cast(TI)) { - // FIXME: implement this! - o << "FIELD INIT not implemented yet!\n"; - } else { - o << "Error: UNIMPLEMENTED\n"; - } - } - } - } - } + emitInstrOpBits(o, Vals, OpOrder, OpContinuous); o << " break;\n" << " }\n"; } + // Default case: unhandled opcode o << " default:\n" << " std::cerr << \"Not supported instr: \" << MI << \"\\n\";\n" << " abort();\n" << " }\n" << " return Value;\n" - << "}\n"; + << "}\n\n"; o << "} // End llvm namespace \n"; } -- cgit v1.2.3